Bitemark Evidence: A Color Atlas and Text, 2nd Edition (International Forensic Science)

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Second Edition

BITEMARK EVIDENCE A Color Atlas and Text

Second Edition

BITEMARK EVIDENCE A Color Atlas and Text Edited by Robert B. J. Dorion

Boca Raton London New York

CRC Press is an imprint of the Taylor & Francis Group, an informa business

CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2011 by Taylor and Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Printed in the United States of America on acid-free paper 10 9 8 7 6 5 4 3 2 1 International Standard Book Number: 978-1-4398-1862-6 (Hardback) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com

Table of Contents

Foreword to the Second Edition Foreword to the First Edition Preface Acknowledgments Contributors

xi xiii xv xix xxi

Section I A Historical Perspective

1

History of Bitemark Evidence

3

David R. Senn

Section II Bitemark Recognition

2

The Role of Health Professionals in Diagnosing Patterned Injuries from Birth to Death

25

John D. McDowell

3

Role of the Medical Examiner, Coroner, and Pathologist

33

Joseph H. Davis

4

The Team Approach in Bitemark Investigation

43

Veronique F. Delattre

Section III Description of the Bitemark

5

The Nature of Bitemarks

53

Mark L. Bernstein

6

Reconstructive Bitemark Analysis

67

Mark L. Bernstein

v

vi Table of Contents

Section I V Collection of Bitemark Evidence A: Noninvasive Analyses

7

Photography

73

Gregory S. Golden and Franklin D. Wright

8

Practical Tips in Forensic Bitemark Photography

103

Luc Gagnon

9

Image Processing and Analysis for Evidentiary Purposes

111

William R. Oliver

10

Bitemarks as Biological Evidence

131

David Sweet O.C.

11

Bitemark Impressions

145

Robert B. J. Dorion

12

Microscopy Techniques

153

Peter J. Bush

13

Nonperishables and Perishables

159

Robert B. J. Dorion

Section I V Collection of Bitemark Evidence B: Invasive Analyses

14

Tissue Specimens

167

Robert B. J. Dorion

15

Histology and Timing of Injury

195

Joseph H. Davis

Section V Bitemark Variables and Cases

16

Animal Bites

209

Richard R. Souviron

17

Carnivore Bitemarks Robert B. J. Dorion

217

Table of Contents

18

Human Bitemarks

vii

241

Robert B. J. Dorion

19

Patterns, Lesions, and Trauma-Mimicking Bitemarks

283

Robert B. J. Dorion and Richard R. Souviron

Section V I Research

20

Current Context of Bitemark Analysis and Research

303

Mary A. Bush and Peter J. Bush

21

Research, Emerging Technologies, and Recent Developments

317

Robert B. J. Dorion

22

Experimental Bitemarks and Histology

433

Michelle Houde

23

Genotypic Comparison of Bacterial DNA Recovered from Bitemarks and Teeth

453

Geoffrey R. Tompkins

Section VII Collection of Evidence from the Suspect

24

The Suspect

463

L. Thomas Johnson

Section VIII Methods of Comparison

25

Methods of Comparison

469

Jon Curtis Dailey

Section I X The Reports

26

Bitemark Report Mark L. Bernstein

493

viii Table of Contents

Section X Prevention and Contamination

27

Precautionary Measures

499

Paul G. Stimson

Section X I Legal Considerations and the Courtroom

28

Science and the Law

507

Richard A. Mincer and Harry H. Mincer

29

Case Law

517

Robert E. Barsley

30

Contracting with the Expert Witness

543

Roger D. Metcalf

31

Courtroom Aids in Bitemark Evidence

561

John P. Kenney

32

Legal Liability of an Expert Witness

569

Haskell M. Pitluck

33

Wrongful Convictions and Erroneous Bitemark Opinions

577

Iain A. Pretty and C. Michael Bowers

Section XII Contentious Issues

34

Reliability of Bitemark Analysis

587

Iain A. Pretty

35

Resolving Issues in Bitemark Analysis

601

Iain A. Pretty

Section XIII Appendices Appendix 1: ABFO Bitemark Analysis Guidelines—Outline

617

Appendix 2: ABFO Guidelines for Investigative and Final Bitemark Reports

619

Table of Contents

ix

Appendix 3: Bitemark Checklist—Bitemark Recipient

621

Appendix 4: Bitemark Checklist—Suspected Biter

625

Appendix 5: Sample Consent Form

629

Appendix 6: Dental Nomenclature

631

Index

633

Foreword to the Second Edition

The analysis of bitemark evidence is clearly the most challenging and arguably the most intriguing aspect of forensic dentistry. And the stakes involved are high, because the bitemark evidence in a case may well be the key factor in determining whether a human being will be exonerated or sentenced to death. The Arizona case of State v. Krone and the Florida case of Bundy v. State, discussed in Chapter 1, are just two of many cases in point. In 2003, Dr. Robert B. J. Dorion decided that there was a need to assemble the best in-depth knowledge available regarding bitemark evidence and create a highquality text that would be a valuable and unprecedented tool for case work, research, teaching, and any other activity involving bitemarks. He developed a team of 21 exceptionally well-qualified contributors and worked industriously to assist them. The result was the 2005 publication of the first comprehensive text anywhere on the subject of bitemark evidence. As such, it is a landmark in the field of forensic science. The outstanding reception received by the first edition validated Dr. Dorion’s foresight and is a tribute to all who contributed to that monumental work. That edition also provided a solid foundation for enhancements, and the book you are now reading is a major step forward from the excellent first edition. The editor has maintained his insistence on quality and has added new

topics, new contributors, and new chapters. Some chapters, such as Chapter 1, have been extensively rewritten and expanded. Others have been updated. The book is larger, even more comprehensive, and has far more color photographs than the first edition. Recent years have seen challenges to the legitimacy of various types of pattern analysis and this has certainly included bitemark analysis. These issues are addressed in depth in this text, starting at the end of the opening chapter. Much additional material presenting both the challenges and the responses are found in Chapters 20, 21, 28, and 33–35. I salute Dr. Dorion and the many top-flight individuals involved in this effort for bringing together an awesome amount of information on an important subject in an organized fashion. The text Bitemark Evidence remains unchallenged in its field. Most importantly, I believe that both the novice and the weathered veteran in forensic dentistry who seriously utilize the contents of this book will feel richly rewarded for having done so. I wish the reader well in the adventures that lie ahead. Gerald L. Vale, DDS, MDS, MPH, JD, D-ABFO Past president, American Board of Forensic Odontology; distinguished fellow, American Academy of Forensic Sciences

xi

Foreword to the First Edition

This book, Bitemark Evidence, is a clear and welcome reflection of the maturing of forensic odontology as a science. It is a sign that the field is evolving past its origins in a Frye-era “consensus of experts” and moving into an era of true scientific standards. It is also a signpost, pointing in directions still to be pursued. Those of us who have been in the field for some time can remember when we were hard pressed to find any reference textbooks whatsoever on the subject of forensic odontology, let alone bitemark evidence. This volume was conceived by its editor, Dr. Robert Dorion, to advance current knowledge and techniques in bitemark analysis in the cause of justice. In any branch of science, the questions to be asked must be tempered by the availability of the means to answer them. Dr. Dorion has assembled a team of eminent forensic scientists from the disciplines of forensic odontology, DNA, pathology, and jurisprudence to present their views in the 13 parts of this much needed and long overdue book. The forensic community will surely appreciate the authors for the scope and depth of their knowledge of this fascinating subject. Professionals involved in the administration of justice will find this text to be an indispensable reference in any situation that confronts them with a question on the validity of bitemark evidence. The book will take the reader from the early history of bitemark investigation to the most sophisticated techniques in current use. For years, the Frye rule was the standard for admission of bitemark evidence. The Daubert decision in

1993 radically changed the terms of admission and set the stage for objective and repeatable scientific standards. The decade since Daubert has been characterized by unprecedented growth in all the forensic sciences. Odontology is no exception. We have seen the emergence and development of novel methods of analysis that would have seemed like pure science fiction to the founders of this field. These techniques have had a very real and positive impact in courtrooms throughout the world. The evolution of bitemark investigation in the postDaubert era is well documented in the chapters of this book. Dr. Dorion has performed an invaluable service in presenting the most up-to-date techniques of bitemark analysis in an intelligent and easily referenced manner. He has wisely chosen his contributors, whose aggregate knowledge and experience represent the very backbone of this field. It is my privilege to have known Dr. Dorion since he was a young dental student. I have watched him grow into a leader in his field, and I hold him in the highest esteem. Likewise, I count the other contributors to this volume as valued colleagues and friends. Their work, as presented in these pages, will be an important and lasting contribution to the science of forensic odontology for years to come.

xiii

Arthur D. Goldman, DMD, FAGD, D-ABFO Past president, American Board of Forensic Odontology; past president, American Academy of Forensic Sciences

Preface

The second edition of Bitemark Evidence, an atlas textbook, contains over 1,500 photographs, of which more than 1,300 are in color. It covers everything from the history of bitemark evidence to diagnosis and on through courtroom testimony. The book will interest first responders, emergency room personnel, physicians, pediatricians, dentists, nurses, crime scene investigators, police identification and photography personnel, medical examiners, coroners, path ologists, law enforcement, forensic and social service personnel, lawyers, and judges. The faculties of medicine, nursing, dentistry, and law will find this atlas textbook an invaluable reference in the respective disciplines. The reader will appreciate the complexity, difficulties, and problems encountered by the expert in the field of bitemark evidence and its legal implications. This text is a collective work and as such reflects the knowledge, training, experience, opinions, and research of 27 authors from around the world. The protocols for photography, collection, preservation, and analysis of bitemarks as well as the current and upcoming research are detailed and the legal implications and ramifications discussed. In the realm of death investigation, the coroner, medical examiner, or pathologist is the primary diagnostician, controller of information, and provider of access to material. The emphasis of the textbook is on diagnosis, communications, and cooperation among the different experts. The atlas unravels the mystery of bitemarks in 13 sections. The first section is a new chapter on the historical perspective fittingly described by Senn. His treatment begins with the earliest known bitemark references from the Bible and the Kama Sutra, through old English law, to early cases from around the world. The era of growth and development of bitemark analysis is accentuated by significant cases from Great Britain, Germany, Russia, Norway, Scotland, Canada, Australia, Africa, and the United States. The development of forensic organizations throughout the world is outlined. Lastly, the challenges to the legitimacy of bitemark evidence are described, with particular reference to the 2009 report of the National Academy of Sciences. Section II, on bitemark recognition, is divided into three chapters dealing with the roles of health professionals and personnel from various fields. The teamwork

approach in bitemark recognition, diagnosis, and investigation is emphasized. In Chapter 2, McDowell treats biting associated with domestic violence and child, intimate partner, and elder abuse in the living. Davis (Chapter 3) relates the role of the medical examiner, coroner, and pathologist in bitemark detection and underlines pattern variables. Delattre expresses the rationale and benefits of the teamwork approach in Chapter 4. The importance of developing a teamwork protocol is emphasized as well as the role of each team member. In Section III, Bernstein (Chapter 5) describes the nature of bitemarks from class and individual characteristics to anatomy, variations, and pathology. In Chapter 6, he deals with reconstructive bitemark analysis: quality of the bitemark, profiling the biter and its limitations, and maintaining perspective. Sections IV(A) and IV(B), on the collection of bitemark evidence, are divided into noninvasive and invasive analyses, respectively. The former is made up of seven chapters dealing with digital photography and practical tips, image processing and analysis for evidentiary purposes, bitemarks as biological evidence, bitemark impressions, microscopy, and the handling of perishables and nonperishables. Golden and Wright discuss digital photography in Chapter 7, beginning with the principles of reflection, absorption, fluorescence, and diffusion. The digital armamentaria of cameras, lenses, and flash units are further analyzed. The different uses and types of photography, including infrared (IR), ultraviolet (UV), and alternate light imaging (ALI), are discussed with case presentation. The application of photographic techniques for purposes other than the recording of bitemarks rounds off the chapter. A new chapter by Gagnon (Chapter 8) offers practical tips in forensic bitemark photography. Image processing and analysis for evidentiary purposes is aptly described by Oliver’s new contribution in Chapter 9. He discusses image processing, digital work flow, and software resources. Sweet discusses salivary swabbing and DNA analysis in Chapter 10. The discussion of salivary flow, physiology, cellular content, stability, recovery, storage, and transportation of saliva as well as case examples more than adequately covers the theme. xv

xvi Preface

In Chapter 11, Dorion’s discussion of bitemark impressions includes a description of materials and new inclusions on techniques for hair removal and impression taking. A new contribution by Peter Bush (Chapter 12) explores the rationale, use, materials, and methods employed for confocal laser microscopy (CLM) and the scanning electron microscope (SEM) and provides examples. The last of the noninvasive techniques is addressed by Dorion in Chapter 13. It describes the materials and methods employed in the handling, preservation, storage, and transportation of perishables and nonperishables as well as outlining the factors affecting bitemarks in perishables. The invasive analysis component to the collection of bitemark evidence is composed of two chapters on tissue specimens and histology. In Chapter 14, Dorion discusses skin wetness and dehydration, the ring technique for tissue excision, fixation, storage, postfixation and storage, transportation, and transillumination. Practical examples are demonstrated using the microscope and transilluminated tissue. The examples serve to illustrate the significance of transillumination. Davis eloquently introduces histology and the “timing” of bitemarks in Chapter 15. He points out textbook discordance in estimating the timing of bruises while discussing the differences between abrasion, contusion/bruise, laceration, and postmortem bruising. Histopathology, histochemistry and biochemistry, and critique of the literature reviews help the reader understand the complexities of this evidence. Reliance on color determination for aging bitemarks is called into question. Section V explores bitemark variables while presenting case material in four chapters. In Chapter 16, Souviron deals with animal bites in general, incorporating aquatic and carnivore bites, both fatal and nonfatal, as well as postmortem animal bites while suggesting an animal bite protocol. In Chapter 17, Dorion deals with nonfatal and fatal carnivore bites, including mountain lion, bear, and dog cases. Section 17.3, Forensic Nightmare: Misdiagnosis, exposes how a simple dog bite case evolved into a homicide charge and, 4 years later, resulted in civil litigation against the police, the pathologist, and the odontologist. There is discussion of the significance of pattern distribution, wound patterning, clothing, “blood wiping,” tissue avulsion, and transillumination in case evaluation. Autopsy failures and forensic lessons learned conclude the chapter. Factors affecting bitemark dynamics introduce Chapter 18 on human bitemarks. Of the 100-odd factors involved in bitemark dynamics, Dorion specifically deals with case presentations, cross-referencing several

in other chapters. Hair, orifices, amputation/avulsion, pigmentation, healing, clothing, self-inflicted bitemarks, erectile tissue, and the presence of other trauma are among the subjects discussed. Dorion and Souviron team up in Chapter 19 to resolve issues of patterns, lesions, and trauma-mimicking bitemarks. They discuss healing and healed lesions as well as patterned injuries on the deceased. The reader is warned of the potential for misinterpreting emergency medical treatment or autopsy trauma as bitemarks. The chapter also addresses the issue of unspecified marks and lesions. Section VI on research is one of the major reasons for revising this edition. It incorporates four new chapters. The first, Chapter 20, is “Current Context of Bitemark Analysis and Research,” written by Mary and Peter Bush to include an overview of the National Academy of Sciences report and its implications in bitemark analysis. They discuss the uniqueness of the dentition and skin as an impression material. Chapter 21 by Dorion discusses research, emerging technologies, and recent developments. It contains over 430 color, UV, IR, and ALI photographs of “gold standard” experimental bitemarks from infliction to 9 months postmortem in some cases. It discusses, among others, the topics of the influence of the presence of hair, clothing, extracellular fluid, overlapping bitemarks, lingual markings, muscle perforation, lividity, and freezing. Chapter 22 is another new chapter dealing with experimental bitemarks and histology by Houde, a forensic pathologist and former coroner. She describes the normal porcine skin histology, the microscopic examination of bitemarks on fresh and frozen piglet skin, and the microscopic examination of human bitemarks. Lastly, this section contains an update to Tompkins’s work on genotypic comparison of oral bacteria isolated from bitemarks and teeth in Chapter 23. Section VII comprises the collection of evidence from the suspect. In Chapter 24, Johnson explains questions of court order versus informed consent as well as the means and methods of obtaining the suspect’s dental history, intra- and extraoral photographs, and impressions. Section VIII, on methods of bitemark comparison by Dailey, introduces the concept of test and static bites. Bite exemplars in wax, Styrofoam, animal and human skin, and the dynamic test bites on volunteers, as well as standard dental impression materials, are evaluated. Methods of direct comparison and the avoidance of technical problems regarding dental nomenclature and dental cast inversions in comparison techniques are addressed. The issues of simple versus computer-generated overlays and the respective problems of metric and digital analysis are effectively conveyed. Other comparison techniques,

Preface

three-dimensional pattern analysis, ink immersion, the dental line-up, and other methods of computer-aided visualization are discussed. Pattern recognition ability concludes Chapter 25. In Section IX, Bernstein (Chapter 26) discusses report writing: its goals, objectives, basic qualities, preparation, content, perspective, and security. He suggests measures for maintaining objectivity and addresses the issue of the components for a standard bitemark report. A new contribution includes the topics of disposition of evidence, investigator information, perspective, and security. Stimson points to issues of prevention and contamination in Section X. Various subjects are addressed in Chapter 27, from personnel to autopsy protocol, instruments, and equipment, to bitemark and dental impressions and casts. Section XI deals with legal considerations and the courtroom. The six chapters cover science and the law, case law, courtroom aids in bitemark evidence, and the legal liability of the expert witness. There are two new contributions on contracting with the expert witness, and wrongful convictions. Chapter 28 introduces the reader to the legal system by explaining science and the law, justice versus truth, the adversarial system, and evidentiary restrictions. Mincer and Mincer further discuss the principles of differentiating good from junk science, the importance of objectivity, the interplay and tension between science and advocacy, and how to approach serving as an expert witness in a bitemark case. Barsley discusses the foundation of case law in Chapter 29, the qualification of the expert, and the concept of “degree of certainty.” He delves into the battling experts, qualifying to testify, the expert’s testimony in opinion, and “linkage.” A new chapter by Metcalf (Chapter 30) introduces the notion of contracting with the expert witness. It explains the notion of a valid contract, oral versus written contracts, the offer, the acceptance, and the consideration. A sample contract is included. In Chapter 31, Kenney introduces the topic of courtroom aids in bitemark evidence by emphasizing

xvii

the need for simplicity, clarity, and conciseness on the part of the testifying expert witness. In the early 1970s, the analysis of bitemark evidence consisted of analyzing black-and-white photographs of dubious quality and producing hand-drawn overlays of the suspect dentition for comparison. Kenney itemizes different methods and materials that, historically, have been used in courtroom presentations by forensic dental experts in bitemark cases. The eye-opening Chapter 32 describes the legal liability of the expert witness with specific reference to forensic dentists. Pitluck emphasizes the reasoning behind absolute immunity and the changing concepts regarding that immunity and what to expect in the future. Chapter 33, the other new chapter in this section, written by Pretty and Bowers, discusses wrongful convictions and erroneous bitemark opinions. It describes the anatomy of a wrongful conviction including examples. Section XII, on contentious issues, is divided into two chapters concerning the reliability of bitemark evidence and resolving issues in bitemark analysis. Chapter 34 introduces concepts of reliability, validity, accuracy, sensitivity and specificity, receiver operator characteristics, and positive and negative predictive values. The effects of Daubert and other judicial rulings and the various research projects in bitemark evidence and their effect on statistics are alluded to. Chapter 35, also by Pretty, discusses the human skin as a bitemark registration material and methods of analysis—both physical comparison and molecular biological techniques. Further discussion on the levels of conclusion and uniqueness of human dentition conclude the chapter. Lastly, Section XIII is composed of six appendices that will undoubtedly benefit the reader with their brevity, conciseness, and checklist approach. The views and opinions expressed by one contributor in this edition may or may not coincide with or reflect the views and opinions of the other contributors. An attempt has been made, however, to reflect the contemporary scientific view of the subject matter. Robert B. J. Dorion, editor

Acknowledgments

I would like to thank all those who have contributed directly and indirectly to this project and in particular to the 27 contributing authors, without whom this book could not have been realized. To Dr. Jean Paul Valcourt (in memoriam) and Dr. André Lauzon, former directors of pathology at the Laboratoire de Sciences Judiciaires et de Médecine Légale, for their professionalism, cooperation, and encouragement over the years—and, above all, for having fostered the development of forensic dentistry in Quebec, thank you. Thank you to Drs. Serge Turmel and Louise Nolet, former and current chief coroners for the province of Quebec, for their cooperation. To my dental collaborators at the Laboratoire de Sciences Judiciaires et de Médecine Légale, Drs. Sylvain Desranleau, Sylvain Laforte, Marie-Josée Perron, and André Ruest, thank you for your assistance. Thank you to the forensic photographers in the identification section of the Quebec Provincial Police for their professional attitude and product and, in

particular, Sgt. Luc Gagnon and Agt. Robert Fortin. Other photographs were taken by various police agencies, including the identification section of the Service de Police de la Ville de Montréal (SPVM), the Royal Canadian Mounted Police, the Ottawa-Carleton Police, the Winnipeg Police, and the Bermuda Police. To Dr. Linda J. Wykes, associate professor and William Dawson scholar, School of Dietetics and Human Nutrition, McGill University, thank you for your precious collaboration. Thank you to the Office of the Chief Medical Examiner of the Commonwealth of Kentucky and to the Office of the Commonwealth Attorney of the Commonwealth of Kentucky for their cooperation. Special recognition goes to Louise Reynolds, Felicity Hawthorn, and Terry Maxwell for their cooperation and assistance. Lastly, I thank the various local, national, and international friends and colleagues for the encouragement expressed and the cooperation received in the writing of this edition.

xix

Contributors

Robert B. J. Dorion (editor), BSc, DDS, FACD, D-ABFO; director of forensic dentistry, Laboratoire de Sciences Judiciaires et de Médecine Légale, Ministry of Public Security for the Province of Quebec, Montreal, Quebec, Canada; assistant professor, faculty of dentistry, McGill University; adjunct research assistant professor, Dept. of Oral Diagnostic Sciences, School of Dental Medicine, SUNY at Buffalo; past president, American Board of Forensic Odontology; past president, Canadian Society of Forensic Science; distinguished fellow, American Academy of Forensic Sciences; fellow, Canadian Society of Forensic Science; member of the board of directors of the American Academy of Forensic Sciences. Robert E. Barsley, DDS, JD, D-ABFO; forensic dental consultant to the Orleans Parish Coroner’s Office and the Jefferson Parish Coroner’s Office, New Orleans, Louisiana; professor of comprehensive dentistry, and director, dental oral resources, LSUHSC School of Dentistry, New Orleans; past president, American Society of Forensic Odontology; secretary, American Academy of Forensic Sciences; fellow, American Academy of Forensic Sciences. Mark L. Bernstein, DDS, D-ABOMP, D-ABFO; professor of oral and maxillofacial pathology, University of Louisville School of Dentistry, Louisville, Kentucky; forensic dental consultant to Chief Medical Examiner’s Office, Commonwealth of Kentucky; fellow, American Academy of Forensic Sciences. C. Michael Bowers, DDS, JD, D-ABFO; deputy medical examiner, Ventura, California; associate clinical professor, the Herman Ostrow School of Dentistry, University of Southern California, Los Angeles. Mary A. Bush, DMD; director, the Laboratory for Forensic Odontology Research, School of Dental Medicine, University at Buffalo, State University of New York at Buffalo, New York. Peter J. Bush, BS; director, South Campus Instrument Center; codirector, Laboratory for Forensic Odontology Research, School of Dental Medicine, University at Buffalo, State University of New York at Buffalo; adjunct professor, art conservation, Buffalo State College, Buffalo, New York.

Jon Curtis Dailey, DDS, D-ABFO; part-time private practice in prosthodontics; forensic odontology consultant, State of Massachusetts Medical Examiner’s Office; adjunct faculty, Armed Forces Institute of Pathology; past president, American Society of Forensic Odontology; fellow, American Academy of Forensic Sciences. Joseph H. Davis, MD; retired chief medical examiner, Miami-Dade County, Florida; professor of pathology emeritus, University of Miami; certified by the American Board of Pathology in pathologic anatomy and forensic pathology; past president, American Academy of Forensic Sciences; past president, National Association of Medical Examiners; distinguished fellow and Gradwohl laureate, American Academy of Forensic Sciences. Veronique F. Delattre, BSc, DDS, FAGD, D-ABFO; director of quality assurance and risk management, and professor, University of Texas Dental Branch at Houston, Texas; forensic dental consultant, Harris County Institute of Forensic Sciences, Houston, Texas; fellow, American Academy of Forensic Sciences; fellow, Academy of General Dentistry; charter member, FBI-CJIS National Dental Image Repository Review Panel; recipient, 2008 FBI assistant director’s award for exceptional public service. Luc Gagnon, section head, Crime Scene Module Western Section, Forensic Identity Division, Criminalistics Service, Sûreté du Québec, Montreal, Quebec, Canada. Gregory S. Golden, DDS, D-ABFO; chief odontologist/ deputy coroner, County of San Bernardino, California; assistant professor, School of Dentistry, Loma Linda University, Loma Linda, California; fellow, American Academy of Forensic Sciences. Michelle Houde, MD; retired forensic pathologist and coroner for the Province of Quebec, Canada. L. Thomas Johnson, DDS, D-ABFO, CSCSA; associate medical examiner, Milwaukee County Medical Examiner’s Office, Milwaukee, Wisconsin; professor, dental science, forensic dentistry and public health, Marquette University School of Dentistry, Milwaukee, Wisconsin; past president, American Board of Forensic Odontology; consultant, Wisconsin Department of

xxi

xxii Contributors

Justice, Crime Laboratory Bureau; fellow, American Academy of Forensic Sciences; certified senior crime scene analyst, International Association for Identifica tion, Crime Scene Certification Board; certified law enforcement instructor, Illinois Bureau of Law Enforce ment Standards and Training. John P. Kenney, DDS, MS, D-ABFO, SCSA; deputy coroner and director of identification services, Du Page County, Illinois, Coroner’s Office; associate clinical professor of surgery, Northwestern University Medical School; consultant, Joint POW-MIA Accounting Command, Hickam AFB, Hawaii; secretary and trustee, the Forensic Sciences Foundation; past president, American Board of Forensic Odontology; editorial board, Journal of Forensic Sciences, Journal of Forensic Identification; fellow, American Academy of Forensic Sciences; fellow, American Academy of Pediatric Dentistry. John D. McDowell, DDS, MS, D-ABFO; director, oral medicine and forensic sciences, University of Colorado School of Dentistry; chairman, oral diagnosis, oral medicine and oral radiology, University of Colorado School of Dentistry; past president, American Academy of Forensic Sciences; past president, American Society of Forensic Odontology; fellow, American Academy of Forensic Sciences. Roger D. Metcalf, DDS, JD, D-ABFO; director of the Human Identification Laboratory, Tarrant County Medical Examiner’s District, Fort Worth, Texas; distinguished visiting clinical professor, Texas Wesleyan University, Fort Worth; fellow, American Academy of Forensic Sciences; fellow, American College of Legal Medicine. Harry H. Mincer, DDS, PhD, D-ABFO; dental consultant to the medical examiner, Shelby County, Tennessee; professor and director of oral and maxillofacial diagnostic services, University of Tennessee College of Dentistry; past president American Board of Forensic Odontology; fellow, American Academy of Forensic Sciences. Richard A. Mincer, JD; Hirst Applegate, LLP, Cheyenne, Wyoming; managing editor, University of Memphis Law Review; past president, Defense Lawyers Association of Wyoming. William R. Oliver, MD, MS (computer science), MPA (justice administration); professor and director of anatomic and forensic services, Department of Pathology and Laboratory Medicine, Brody School of Medicine at

East Carolina University, Greenville, North Carolina; network administrator, Scientific Computing Network, Armed Forces Institute of Pathology; former regional medical examiner, Georgia Bureau of Investigation; former deputy medical examiner, Office of the Armed Forces Institute of Pathology; board certified in anatomic, clinical, and forensic pathology; fellow, College of American Pathologists, American Academy of Forensic Sciences, National Association of Medical Examiners; selected as one of Federal Computer Week’s 100 most influential information technology professionals, 1997; finalist, Berry Prize in Military Medicine, 1998; executive committee, Scientific Working Group on Imaging Technology, Applied Imagery Pattern Recognition Workshop; chair, SWGIT Image Analysis Subcommittee. Haskell M. Pitluck, JD; retired circuit court judge (Illinois); past president, American Academy of Forensic Sciences; fellow, American Academy of Forensic Sciences. Iain A. Pretty, BDS (Hons), MSc, MPH, PhD, MFDSRCS (Ed); forensic dentist to the North West Coroner’s Services; forensic consultant to Merseyside and Cheshire Police Forces; senior lecturer in dental public health, School of Dentistry, University of Manchester. David R. Senn, DDS, D-ABFO; clinical assistant professor, dental diagnostic science, University of Texas Health Science Center at San Antonio; director, Center for Education and Research in Forensics; chief forensic odontologist, Bexar County Medical Examiner, San Antonio, Texas; fellow, American Academy of Forensic Sciences. Richard R. Souviron, DDS, D-ABFO; chief forensic odontologist, Miami-Dade County Medical Examiner’s Office, Florida; adjunct professor, pathology, University of Miami School of Medicine; past president and founding member, American Board of Forensic Odontology; fellow, American Academy of Forensic Sciences; founding member of the Odontology Section of the American Academy of Forensic Sciences. Paul G. Stimson, DDS, MS, D-ABFO, D-ABOMP (emeritus); senior forensic consultant, Harris County Forensic Center, Office of the Medical Examiner, Houston, Texas; professor emeritus, University of Texas Dental Branch at Houston, University of Texas Health Science Center at Houston; past president, American Board of Forensic Odontology; past president and member emeritus, American Society of Forensic Odontology; fellow, American Academy of Forensic Sciences; DMORT team member.

Contributors

David Sweet O.C., DMD, PhD, D-ABFO; director, Bureau of Legal Dentistry Laboratory, University of British Columbia, Vancouver, Canada; professor, faculties of dentistry and medicine, the University of British Columbia, Vancouver, Canada; consultant forensic odontologist, Office of the Chief Coroner, British Columbia Coroners’ Service, Burnaby, Canada; consultant forensic odontologist, Royal Canadian Mounted Police Forensic Laboratory Services Directorate, Ottawa, Canada; fellow, American Academy of Forensic Sciences.

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Geoffrey R. Tompkins, PhD; senior lecturer, Department of Oral Sciences, and director, Oral Microbiology and Dental Health Research Theme, University of Otago, Dunedin, New Zealand; past president, Georgia Chapter, American Association for Dental Research. Franklin D. Wright, DMD, D-ABFO; forensic dental consultant, Hamilton County Coroner’s Office, Cincinnati, Ohio; fellow, American Academy of Forensic Sciences.

A Historical Perspective

I

1

History of Bitemark Evidence David R. Senn Contents

1.1 Introduction 1.2 Early History of Bitemarks 1.2.1 From the Beginning through the Middle Ages 1.2.1.1 The Garden of Eden 1.2.1.2 The Kama Sutra 1.2.1.3 The Orkneyinga Saga 1.2.1.4 William the Conqueror (William I of England; William II, Duke of Normandy) 1.2.2 1600 to 1950 1.2.2.1 Mayhem and the Ancient Law of England, Seventeenth Century 1.2.2.2 Indentured Servitude, Seventeenth Century 1.2.2.3 Salem Witch Trials, 1692 1.2.3 Other Nineteenth and Early Twentieth Century Cases 1.2.3.1 The Coram Street Affair, London, 1872 1.2.3.2 The Woods of Chantilly 1.2.3.3 The Gangs of New York, Late Nineteenth Century 1.2.3.4 Transparent Overlays in Bitemark Analysis, Germany, 1924 1.2.3.5 Ohio v. Robinson, Ohio, United States, 1870 1.2.4 Additional Cases 1.2.4.1 Teeth Marks in Cigar Holders, Russia 1.2.4.2 Bitemark in Cheese, Germany, 1905 1.2.4.3 Bitemark in Cheese, England, 1906 1.2.4.4 The Heath Case, England, 1946 1.2.4.5 The Gorringe Case, England, 1948 1.2.4.6 Tunbridge Wells, England, 1949 1.2.5 Cases in Canada 1.2.5.1 Nova Scotia, 1924 1.2.5.2 Quebec, 1930 1.3 Bitemark Evidence in the Modern Era (1950–2010): Cases Leading to the Acceptance of Bitemark Evidence in Courts of Law 1.3.1 Doyle v. State, 1954 (Texas) 1.3.2 Wayne Clifford Boden, 1968–1971 (Canada) 1.3.3 People v. Johnson, 1972 (Illinois) 1.3.4 People v. Marx, 1974 (California) 1.3.5 State v. Bundy, 1979, 1980; Bundy v. State, 1984 (Florida) 1.3.6 Other Significant Cases 1.3.6.1 State v. Milone, 1973 (Illinois) 1.3.6.2 Wilhoit v. State, 1991 (Oklahoma) 1.3.6.3 People v. Moldowan and Cristini, 1991; People v. Moldowan, 2002; People v. Cristini, 2004 (Michigan) 1.3.6.4 State v. Krone, 1992, 1995 (Arizona) 1.3.6.5 State v. Brewer, 1995; Brewer v. State, 1998, 1999 (Mississippi) 1.3.7 Cases in Modern Europe and the United Kingdom 1.3.7.1 Fredrik Fasting Torgersen, Oslo, Norway, 1957 1.3.7.2 Gordon Hay, Biggar, Scotland, 1967 3

4 4 4 4 5 5 5 7 7 7 7 7 7 7 8 8 8 9 9 9 9 9 9 9 10 10 10 10 10 10 11 11 12 12 12 13 14 14 14 15 15 16

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

1.3.8 Cases in Modern Africa 1.3.8.1 State v. Shabangu, 1998 1.3.8.2 State v. Nxele, 1999 1.3.8.3 Vierfontein, Free State, 2002 1.3.9 Cases in Modern Australia 1.3.9.1 Ipswich, Queensland, 1973 1.3.9.2 Darwin, Northern Territory, 1986 1.4 Forensic Odontology Organizations 1.4.1 International Organization for Forensic Odontostomatology (IOFOS) 1.4.2 The Odontology Section of the American Academy of Forensic Sciences (AAFS) 1.4.3 The American Society of Forensic Odontology (ASFO) 1.4.4 Canadian Society of Forensic Science (CSFS), Odontology Section 1.4.5 American Board of Forensic Odontology 1.5 History of Bitemark Education in North America 1.5.1 Armed Forces Institute of Pathology (AFIP) 1.5.2 McGill University and the Laboratoire de Sciences Judiciaires et de Médecine Légale (LSJML) 1.5.3 University of Texas Health Science Center at San Antonio Dental School 1.5.4 Bureau of Legal Dentistry (BOLD) 1.5.5 Other Courses 1.6 Challenges to the Legitimacy of Bitemark Evidence 1.6.1 Bitemark Evidence Controversies 1.6.2 National Academy of Sciences 2009 Report 1.7 Perspective on the Relationship between the Past and Future of Bitemark Evidence Acknowledgments References

1.1â•…Introduction When human teeth contact objects or surfaces or, alternately, those objects or surfaces contact the teeth, a mark or marks may be left. Human teeth are capable of marking almost any material that is softer than the enamel that covers their crowns. Not all of these marks should be called bitemarks. Those marks that occur as a result of objects or surfaces striking the teeth are more accurately called teeth marks. Bitemarks are created by the dynamic actions of the mouth and jaw complex of a person or animal. In human interactions, biting is known to occur in situations ranging from play to lovemaking and, more malevolently, in violent interchanges, such as fights and frays, and criminal activities from assaults to homicides. Bitemarks and teeth marks can be dangerous to the health of their recipients. Closed-fist teeth mark injuries of the type seen in fistfights may result in serious infections, amputations, and even death [1]. In those instances that result in bitemarks, the biter may be a willing participant, an assailant, or a person assailed acting in self-defense. Bitemarks occur more frequently during these activities than most imagine. Some earlier societies have considered the teeth to be weapons necessary for defense in battle. Practitioners of forensic odontology confirm that the teeth are used

16 16 16 17 17 17 17 18 18 18 18 18 18 19 19 19 19 20 20 20 20 20 21 21 21

as both defensive and offensive weapons. Teeth marks and bitemarks that have legal repercussions have been recorded in food such as cheese, sandwiches, fruit [2,3], food containers, and expanded polystyrene cups [4], as well as on other objects ranging from cigar holders [5,6] to duct tape bitten while immobilizing a victim [7,8] to a truck window trim strip bitten by a victim during sexual assault [9]. The resulting teeth marks and bitemarks often become important physical evidence in legal cases that deal with the disorder, havoc, injury, and mayhem of which humans are capable.

1.2â•…Early History of Bitemarks 1.2.1â•…From the Beginning through the Middle Ages 1.2.1.1â•…The Garden of Eden In the first edition of Bitemark Evidence, Vale discussed the roles of Eve, Adam, and the serpent in the allegorical biting of the forbidden fruit [10]. This may be considered by some the first case to include bitemark evidence. If that were true, it could also be considered the least controversial bitemark case; there were no lawyers, no dental experts, no jury, and only one judge. Both suspects confessed their joint culpability. One could argue,

History of Bitemark Evidence

perhaps, that groundwork was laid for future cases involving bitemarks in food, including apples. 1.2.1.2â•…The Kama Sutra The ancient Sanskrit compendium text first published in its current form in the second century CE includes a list of various types of bites and describes their roles in lovemaking and beyond. Although certainly not forensic in nature, these descriptions can be considered the earliest known classification system for bitemarks. The types of bites listed are the hidden bite, the swollen bite, the point, the line of points, the coral and the jewel, the line of jewels, the broken cloud, and the biting of a boar. The Kama Sutra [11] further describes each of the bite types: The biting, which is shown only by the excessive redness of the skin that is bitten, is called the “hidden bite.” When the skin is pressed down on both sides, it is called the “swollen bite.” When a small portion of the skin is bitten with two teeth only, it is called the “point.” When such small portions of the skin are bitten with all the teeth, it is called the “line of points.” The biting, which is done by bringing together the teeth and the lips, is called the “coral and the jewel.” The lip is the coral, and the teeth the jewel. When biting is done with all the teeth, it is called the “line of jewels.” The biting, which consists of unequal risings in a circle, and which comes from the space between the teeth, is called the “broken cloud.” This is impressed on the breasts. The biting, which consists of many broad rows of marks near to one another, and with red intervals, is called the “biting of a boar.” This is impressed on the breasts and the shoulders; and these two last modes of biting are peculiar to persons of intense passion. Both the “line of points” and the “line of jewels” are to be impressed on the throat, the arm pit, and the joints of the thighs; but the “line of points” alone is to be impressed on the forehead and the thighs.

The Kama Sutra [11] also offers advice on personal behavior following being bitten:

5

ostensibly to discuss and peacefully settle differences. Sigurd arrived at the meeting with double the agreed force by placing two men on each horse. Although Maelbrigte recognized the treachery in advance, noting two legs on each side of every horse, he and his men engaged the Norwegians. They fought bravely but were overwhelmed and killed by the superior force. Sigurd ordered the beheading of the defeated Scots. Their severed heads were tied to the saddles of Sigurd and his men to make a show of the victory. As Sigurd spurred his horse for the triumphant ride home, he struck his bare calf against the protruding teeth of Maelbrigte’s head slung from his saddle. The resulting injury led to infection, swelling, fever, and, ultimately, to the death of Sigurd the Mighty. He is buried on the bank of the Oykel River near the present-day Scottish town of Dornach [12]. 1.2.1.4â•…William the Conqueror (William I of England; William II, Duke of Normandy) It has been previously reported that William, the Norman conqueror of Britain at the 1066 Battle of Hastings, would sometimes seal official documents by biting his teeth into the wax seals affixed [13]. In The Curiosities of Heraldry, Mark Antony Lower reported that William gave an estate near Leeds in York to a family named Roydon. There are two separate but similar accounts of the wording of the deed. Only one refers to the biting of wax and that document is questionable and no longer exists. The elusive title deed, which would have been created around 1069 CE, was “formerly in the possession of the family” [14] (FigureÂ€1.1). A similarly worded version omits the biting of the wax [14]: I, William King, give to thee, Powlen Rowdon, my hop and my hoplands, with all the bounds up and downe, from Heaven to Earth, from Earth to Hell, for thee and

When a man bites a woman forcibly, she should angrily do the same to him with double force. Thus a “point” should be returned with a “line of points,” and a “line of points” with a “broken cloud,” and if she be excessively chafed, she should at once begin a love quarrel with him.

The love quarrel, then as now, was apparently much dreaded. 1.2.1.3â•…The Orkneyinga Saga This history of the Orkney Islands of Scotland includes an account of fatal teeth marks. In the year 892, a Norwegian earl, Sigurd (the Mighty), arranged a meeting with a rival Scottish earl, Maelbrigte (the Bucktoothed),

Figure 1.1â•‡ Title deed transferring land from King William to the Roydon family.

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition thine to dwell, from me & mine to thee & thine, for a Bowe and a broad Arrow, when I come to hunt upon Yarrow; in witnesse Magge, Maude, and Margery, & my third Son Henery.

That the teeth were used in ancient times to mark sealing wax, however, is clearly seen in one of two beautifully illustrated books privately published in 1847, Sigilla Antiqua, 2nd Series [15]. The volume contains high-quality engraved images of ancient wax seals. The first image of plate 1 in volume 2 depicts an engraving of a wax seal containing the imprints of anterior teeth. The exact date of the transfer is unknown, but the postscript indicates that the transfer occurred during the reign of Edward II (1284–1327) (FiguresÂ€1.2 and 1.3).

As a postscript to the second series, Sir Thomas Hare, baronet of Stowe-Bardolph and sponsor of the series, added, “It has been said that before the use of Seals was in England, divers writing had the wax of them bitten with wang tooth of him that passed them.” Taylor notes that they sometimes include the inscription shown in FigureÂ€1.4. He adds, “What amount of truth there may be in this assertion I pretend not to say: we have here, however, at a later period, an example in which, for lack of Seal, the fair Agnes has sharply impressed the form of her teeth upon the wax” [15]. Though the teeth shown in the figure are clearly anterior teeth, the term “wang” tooth usually refers to a “cheek” or “jaw” tooth, generally understood to mean a molar [16].

Figure 1.2â•‡ “No. 1. The impression of teeth on wax, in place of Seal, of Agnes the daughter of Agnes, daughter of Willim Fiz of Fyneham, to a Deed by which she enfeoffs Adam de Fyneham, in one acre and three roods of land there. S.D. temp. Edw. 2.” (Taylor and Hare. 1847. Sigilla Antiqua. Engravings from Ancient Seals Attached to Deeds and Charters in the Muniment Room of Sir Thomas Hare. Stowe-Bardolph. Priv. print. 1 p.l., 14 l 15.)

Figure 1.3â•‡ Numbers 1 through 3 of the engravings of ancient wax seals as seen in Sigilla Antiqua. (Taylor and Hare. 1847. Sigilla Antiqua. Engravings from Ancient Seals Attached to Deeds and Charters in the Muniment Room of Sir Thomas Hare. Stowe-Bardolph. Priv. print. 1 p.l., 14 l 15.)

Figure 1.4â•‡ According to Taylor, inscriptions such as this sometimes accompanied bitemarks in wax.

History of Bitemark Evidence

1.2.2 1600 to 1950 1.2.2.1 Mayhem and the Ancient Law of England, Seventeenth Century In seventeenth century England, the act of humans biting humans during violent interchanges was well known. According to the Lawes of England, the loss of the teeth at the hands of another was considered to be the crime of mayhem, depriving one of “a member proper for his defense in fight.” During that period in England, mayhem was punishable by death [17]. This interesting ancient law clearly illustrates a fact well known to modern forensic odontologists but perhaps not as widely known generally: People often bite other people, especially during violent interaction. 1.2.2.2 Indentured Servitude, Seventeenth Century Debtors and others desiring passage to the New World would often enter into agreements with entrepreneurs who financed their passage. They agreed either to work for a specified period of time or to repay the agreed amount. Some would verify the agreement by biting into the document seals in lieu of or in addition to signatures. They were referred to as indentured servants [18]. An alternate explanation of the term refers to the practice of drawing up the agreement in duplicate, then cutting or tearing between them in a zigzag manner so that the two halves of the document could be fitted together to assure authenticity [19]. 1.2.2.3 Salem Witch Trials, 1692 In her deposition, 17-year-old Mary Walcott testified that “Mr. George Burroughs or his Apperance came to me whom I formerly well knew and he did immediately most greviously torment me by biting pinching and almost choacking me urging me to writ in his book” [20]. Similar depositions and testimony against the lay minister led to his being tried as a male witch or wizard. The indictments cited those depositions and listed [20] Sundrey other Acts of witchcrafts by Said George Burroughs upon the bodies of Mary Walcot, Marcy Lewis, Abigail Williams, Ann Putnam and Eliz. Hubbard and Susan Sheldon Upon Som: or all of them, of Salem Village or farm[es] whereby great hurt and dammage benne donn[e] to the Bodys of s’d persons above named therefore Craved Justice.

Burroughs protested his innocence and stated that he was incarcerated at the time of most of the accused occurrences. The alibi was circumvented by claims that Burroughs’s specter, the previously mentioned “Apperance,” did the actual biting. His mouth was pried

7

open in court and it was declared that he was the biter. Burroughs was convicted. Mr. Burroughs was carried, through the streets of Salem to Execution; when he was upon the Ladder, he made a Speech for the clearing of his Innocency, with such Solemn and Serious Expressions, as were to the Admiration of all present; his Prayer (which he concluded by repeating the Lord’s Prayer) was so well worded, and uttered with such composedness, and such (at least seeming) fervency of Spirit, as was very affecting, and drew Tears from many (so that it seemed to some that the Spectators would hinder the Execution). (Calef [21])

It was widely believed that witches could not recite the Lord’s Prayer. Unfortunately, Burroughs had a religious rival, Rev. Cotton Mather, who believed him to be, unforgivably, both a witch and a Baptist! Mr. Cotton Mather, being mounted upon a Horse, addressed himself to the People, partly to declare, that he [George Burroughs] was no ordained minister, and partly to possess the People of his guilt; saying, That the Devil has often been transformed into an Angel of Light. In doing this he reassured the crowd of Burroughs’ guilt and the execution proceeded. (Calef [21])

George Burroughs was executed on August 19, 1692. As Vale prophetically stated in the first edition, “Thus, the Salem Witch Trials provide a thought-provoking backdrop for the introduction of bitemark evidence into the American judicial system” [10]. 1.2.3 Other Nineteenth and Early Twentieth Century Cases 1.2.3.1 The Coram Street Affair, London, 1872 In his 1937 book, The Criminals We Deserve, Henry T. F. Rhodes cites cases involving bitemark evidence. In the Bloomsbury district of London, the Coram Street affair of 1872 concerned the murder of a prostitute. A German pastor was accused and part of the evidence was a bitemark in an apple. The evidence was poorly managed and the pastor had strong political influence. He was acquitted [22]. 1.2.3.2 The Woods of Chantilly Rhodes also cites the successful prosecution of a man for attempted rape in the woods of Chantilly. During the attack, the victim bit the attacker and escaped. The suspect claimed the injury to his right hand was not a result of a bite. “But under the skilled examination of an expert in identification they were proved to correspond

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

at ten points with the marks made by the girl’s teeth. The man was convicted” [22]. 1.2.3.3 The Gangs of New York, Late Nineteenth Century In the last 20 years of the nineteenth century, tough guys and professional thugs in the gangs of New York could be hired to maim and murder. Rhodes published a tariff found on one of those thugs, Piker Ryan, when he was arrested [22]. The tariff included the following disturbing price list: Punching Both eyes blacked Nose and jaw broke “Jacked” out Ear chawed off Leg or arm broke Shot in leg Stab Doing the big job

2 dollars 4 dollars 10 dollars 15 dollars 15 dollars 19 dollars 25 dollars 25 dollars 100 dollars and up

Avulsive bitemarks of ears are not uncommon in violent interchanges today. The bizarre antics of Mike Tyson in his boxing match with Evander Holyfield form a wellknown example. 1.2.3.4 Transparent Overlays in Bitemark Analysis, Germany, 1924 Ferdinand Strom, among others, noted that the German forensic odontologist A. Sorup was an early investigator of bitemarks. In a 1924 case Sorup reported the use of transparent paper representations of suspects’ dentitions compared to life-sized images of bitemarks [23,24]. These may be considered as precursors to the more modern transparent overlays. In a notably comprehensive chapter on bitemarks in his still impressive 1976 book, Dental Identification and Forensic Odontology, Harvey referred to cases with bitemark evidence occurring prior to 1950 in North America (1925, 1944), the United Kingdom (1937), and Germany (1929, 1932, 1938) [3]. 1.2.3.5 Ohio v. Robinson, Ohio, United States, 1870 In 1990, Pierce, Strickland, and Smith published an article describing an 1870 case involving bitemark evidence [25]. This is very likely the first case in North America that included the testimony of a dentist in a bitemark case. Records of the trial are sparse and most of the information about it comes from newspaper accounts. Ansil L. Robinson was charged with the murder of his mistress, Mary Lunsford. Prosecutors introduced evidence that

alleged Robinson had left bitemarks on the victim’s arms. “A further examination revealed a large cut in her abdomen and her arm showed five bites, the print of teeth being plainly visible” [26]. Three dentists, Dr. C. R. Taft and Drs. DeCamp and Watt, testified at trial for the prosecution. All three agreed upon these points: The marks on Mrs. Lunsford’s arm were of teeth made by biting. The marks were plain and easily observed. There was also a distinct area of ecchymosis associated with the injury. The teeth of each individual are unique. The marks made by a set of teeth can be distinguished from marks made by another set of teeth. The teeth do not imprint well into the tissue of the arm. The marks could be evaluated. There were five distinct teeth marks demonstrated in the bite. The models of Robinson’s teeth fit well into the marks. Robinson’s teeth had made the marks. For the defense, a physician testified and described his unusual examination technique. At the scene, shortly after the body had been discovered, a Dr. Whitney bit the victim’s arm “with his own teeth” to compare his teeth marks with those already present. The article reports that he also later asked Robinson to bite his (Dr. Whitney’s) arm, in order to compare the mark with those on the body of Lunsford. Three other physicians testified for the defense. The judge summarized the case presentations in his instructions to the jury [26]: It is claimed that the deceased when first discovered, had marks on the arm of a bite of the human mouth— that they must have been inflicted at the time of the killing—that a model or copy of the defendant’s mouth was then obtained: and when tested and applied directly to the arm and marks, it corresponded and agreed accurately in every particular. It is further claimed by the State that the model is an accurate copy of the defendant’s mouth, and the mode of taking it is reliable—that the human teeth, by a bite will be distinctly and accurately imprinted on the human arm: that the diversity of human mouths is almost infinite and endless: that the diversity is so great that no two exactly alike can be found: that the distinctive peculiarities of the defendant’s mouth are even greater than is ordinarily found. For the defendant, it is claimed that the mode of taking the model of his mouth is unreliable and consequently the models are inaccurate: that the human teeth will not be accurately imprinted on the human arm by

History of Bitemark Evidence a bite and that an accurate, or reliable test cannot he made by the application of a model of a mouth to the marks of a bite on the arm: that there is such a general uniformity of human mouths that the means employed by the State to ascertain and identify the mouth that inflicted the bites cannot be relied on in the case.

The jury deliberated for 6 hours and found Robinson not guilty. The procedures used, testimony given, and legal points cited are all remarkably similar to those of many cases that followed. 1.2.4 Additional Cases 1.2.4.1 Teeth Marks in Cigar Holders, Russia In Teeth That Told, Keiser-Nielsen offers an account of a Russian case reported in a doctoral thesis at the University of Lyon in France. An expensive amber cigar holder found at a murder scene contained clearly visible depressions presumably caused by the irregular teeth of the owner. The depressions did not fit the victim, so the investigators theorized that the holder may have belonged to the killer. During the inquest, the judge asked a cousin of the victim during his testimony to try the holder in his mouth. The cousin “went pale and refused.” He was immediately arrested and his teeth “fitted exactly” into the depressions in the cigar holder [4,6]. 1.2.4.2 Bitemark in Cheese, Germany, 1905 During a robbery in Germany in 1905, the culprit took a “goodly bite” out of a piece of Swiss cheese and left it on a windowsill. Police had a plaster cast made of the cheese. The resulting model showed an abrasion on the left side that was interpreted as a “pipe hole,” implicating one of several suspects [2]. 1.2.4.3 Bitemark in Cheese, England, 1906 In a 1906 burglary case in County Cumberland in northern England, a piece of cheese allegedly bitten by one of two accused burglars was brought into evidence. Dental impressions were made and resulting models compared to the cheese. The teeth of one of the two accused men were judged to fit the bitemark in the cheese, leading to the conviction of that man [3]. In a 1925 murder trial in Boston, the prosecutors claimed that marks on the left forearm of a murdered policeman were teeth marks and that the defendant’s lower anterior teeth, as shown in plaster of Paris models, “fitted these marks.” As a single arch “bitemark,” the prosecution theorized that the dead policeman’s rubber coat sleeve may have blocked the upper teeth. Over 1,000 mouths were inspected in an attempt to find teeth resembling the alignment seen in the bitemark

9

and the defendant’s teeth. Impressions of more than a dozen of the most similar mouths failed to produce models that corresponded as well to the indentations in the skin as the defendant’s. The mark had been excised and stored in formalin. The changes in the excised skin compromised the accuracy of the prosecution’s case. The sketches of the indentations in the skin made at autopsy and 13 days later showed changes that did not correspond with measurements of the defendant’s teeth, weakening the prosecution’s case [27]. 1.2.4.4 The Heath Case, England, 1946 The well-known forensic pathologist, Professor Keith Simpson, was involved in a famous murder case with bitemarks. Neville Heath, by all accounts, was an attractive and charming young man, but a habitual liar with unsavory habits. On June 20, 1946, he took Margery Gardner to London’s Pembridge Court Hotel after drinking at a local club. The next morning the maid found Gardner’s badly beaten and lifeless body tied on the bed. The nipples of both breasts were almost bitten off. Heath fled London to Bournemouth, changing his name to Group Captain Rupert Brooke. There he met and murdered Doreen Marshall. Her body was not found until after Heath had been arrested and returned to London under suspicion for the Gardner murder. Two deep knife wounds to the throat had killed Marshall. One nipple had been completely bitten off. Simpson was unable to link Heath definitively to the Gardner breast bitemarks due to the severity of the injuries. Heath was tried in September 1947 and found guilty. He was hanged October 16, 1946, at Pentonville Prison [28]. 1.2.4.5 The Gorringe Case, England, 1948 Professor Simpson utilized bitemark analysis in another case. His testimony contributed to the evidence that led to the conviction of Robert Gorringe for the murder of his wife, Phyllis. Simpson’s opinion to the court that the bitemarks on Mrs. Gorringe’s body were made by her husband was one of the first recorded instances of forensic odontology evidence in an English court being used to relate the teeth of a biter to bitemarks on skin [29]. 1.2.4.6 Tunbridge Wells, England, 1949 Professor Simpson was also involved with the investigation of a New Year’s Day, 1949, murder in Kent. A girl had been killed in the back of a lorry, behind the police station in Tunbridge Wells. Her head had been battered in, she had been sexually assaulted, and there was a bitemark on her right breast. Unable to locate a dentist in the early hours of the morning after the crime, Professor Simpson himself took the dental impressions of the suspect. The unfortunate girl’s husband was arrested,

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 1.5â•‡ The earliest known archival photographs of multiple human bitemarks in an infanticide/homicide case from Quebec, Canada, 1930. (Photos courtesy of Dr. Robert Dorion.)

charged, and convicted. Again, no dentist was involved in the prosecution of this case, but dental evidence played an important role [30]. 1.2.5â•…Cases in Canada 1.2.5.1â•…Nova Scotia, 1924 The first known bitemark case in Canada occurred in Sheet Harbor, Nova Scotia, in 1924. Two local dentists, Drs. Bagnall and Faulkner, identified the bitemarks in an apple left at the scene of a burglarized clothing store as belonging to the teeth of the suspect, William Steele. He was convicted of burglary [31]. 1.2.5.2â•…Quebec, 1930 In a 1930 Quebec case, a murdered infant was found with multiple bitemarks (FigureÂ€ 1.5). This may be the first North American case of human bitemarks on skin that is documented by archival photography [10].

1.3â•…Bitemark Evidence in the Modern Era (1950–2010): Cases Leading to the Acceptance of Bitemark Evidence in Courts of Law 1.3.1â•… Doyle v. State, 1954 (Texas) The first reported case in the United States involving bitemarks was an appellate case. In the original case, Doyle had been accused of burglary and he allegedly left his bitemark in cheese at the scene (FigureÂ€1.6). This first reported U.S. case is significant for establishing admissibility in a court of law of bitemarks in food. A firearms examiner, with supporting testimony from a dentist, gave the testimony concerning the pattern evidence. At issue in the appeal was the manner in which the evidence from the alleged biter was collected. Mr. Doyle was asked to bite into another piece of cheese, which he did voluntarily. This evidence was introduced at trial and compared with the cheese from the crime scene, establishing a link between Mr. Doyle and the burglary. Doyle was

Figure 1.6â•‡ Model of a bitemark in cheese in Doyle v. State.

convicted and the conviction was appealed later that same year on the grounds that Doyle’s constitutional rights were violated. The appellant claimed that a court order had not been issued for the gathering of evidence in violation of the Fourth Amendment, protection from illegal search and seizure, and the Fifth Amendment, the right to protection from self-incrimination. The appeals court denied Doyle relief on both issues [32]. 1.3.2â•…Wayne Clifford Boden, 1968–1971 (Canada) Boden was a Canadian serial killer also known as the “vampire rapist” because he left bitemarks on the breasts of several of his victims. This was the first known case in the Canadian courts in which bitemarks in human skin were used to identify a perpetrator. Dr. Gordon C. Swann, a Calgary orthodontist, compared casts of Boden’s teeth to the bitemarks on the breast and neck of a 1971 murder victim, Elizabeth Ann Porteous. Using a system of direct geometric progression modified from a method described by Furness [33], he identified 29 points of similarity leading him to conclude that “the bitemarks on the body of Porteous were indeed inflicted by the teeth of the accused Wayne Clifford Boden.” Dr. Swann also reviewed evidence in three earlier murders in Montreal with similar features. He was unable to associate Boden with two of those cases but found 17 points of similarity to a bitemark on the breast of the October 1969 victim, Shirley Audette. Boden was transferred to Montreal, where forensic odontologist

History of Bitemark Evidence

Dr. Araceli Ortiz, assisted by a fourth-year dental student, Robert Dorion, took dental impressions of Boden at the maximum-security Saint Vincent de Paul Penitentiary. Boden eventually confessed to the three Montreal murders and received four life sentences. In a bizarre turn of events, Boden was able, while in prison, to apply for and receive an American Express credit card. In the fifth year of his life sentence, during an escorted day-pass excursion from prison, he escaped through the bathroom window of the Montreal Sheraton Hotel’s Kon Tiki restaurant. Using the credit card, he enjoyed 36 hours of freedom until he was recaptured at a nearby bar—the same one where he had met some of his victims 15 years earlier. Boden died of skin cancer in a prison hospital in 2006 [34]. 1.3.3â•… People v. Johnson, 1972 (Illinois) In the first recorded case in the United States involving a bitemark in human skin, Johnson was accused of rape and aggravated battery. There was a bitemark on the breast of the victim. An Illinois dentist, Dr. Paul Green, testified that Johnson’s teeth were similar to the bite pattern on the breast of the victim. “Finally an oral pathologist in comparing a cast of defendant’s teeth with a photograph of the teeth marks on complainant’s breasts expressed the opinion that it was highly probable

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the teeth marks on the breasts were made by Johnson’s teeth.” Johnson was convicted of rape and aggravated battery and his conviction was upheld at the appellate level [35]. 1.3.4â•… People v. Marx, 1974 (California) This was the first case in the state of California involving bitemark evidence. Walter Marx was charged with the murder of Lovey Benovsky. An alleged bitemark was the only physical evidence offered by the prosecution. The elderly female victim had been sexually assaulted and strangled. In February of 1974, Marx was jailed for contempt of court for refusing to provide dental casts pursuant to a court order. Marx later consented to the impressions. At autopsy, the pathologist believed a patterned injury to be a possible bitemark but no bitemark evidence was collected at that time. Following autopsy, the body was embalmed and buried in Texas. In March, after Marx finally agreed to the teeth impressions, Benovsky’s body was exhumed; a Dallas dentist made photographs and impressions of the nose and this material was sent to California (FigureÂ€1.7). Three forensic dentists worked both independently and together on the analysis of the bitemark, the first known case of a team approach to testing, evaluation, and comparison of a bitemark on the skin of a victim to the

Figure 1.7â•‡ Images of the nose (left) and three-dimensional model (right) of the bitemark on the nose of Lovey Benovsky. The dental models compared are those of Walter Marx.

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

teeth of a suspect. Test bites were performed in this case and a three-dimensional model of the nose was made. Overlays, three-dimensional comparisons, and scanning electron microscopy were also used. None of these techniques had been documented as having been used in previous cases. Direct comparisons were also made utilizing the dental casts from the only suspect, Walter Marx, to the three-dimensional model of the nose. The three dentists, Drs. Gerald Felando, Reidar Sognnaes, and Gerald Vale, testified at trial. All agreed that the teeth of Walter Marx made the bitemark in the nose of Lovey Benovsky. The admissibility of the bitemark evidence and the conviction of Walter Marx were challenged and upheld on subsequent appeals, effectively establishing the legal acceptability of bitemark evidence. Without the bitemark evidence, the prosecution did not have a strong case against Marx. He was convicted of voluntary manslaughter, not murder, based in part on the testimony of a psychiatrist [36]. tate v. Bundy, 1979, 1980; 1.3.5â•… S Bundy v. State, 1984 (Florida) Theodore Robert Bundy was believed to have killed many young women across the United States from Washington to Florida. He had escaped prison in Colorado and settled in Florida. He was arrested after a traffic violation and held on suspicion of two murders and the assaults on three other female victims in Tallahassee, Florida, in January of 1978. One of the Florida State University Chi Omega sorority house murder victims had patterned injuries on her left buttock suggesting bitemarks. One photograph out of the thousands taken at the scene and at autopsy included a ruler held near the patterned injury. This photograph allowed the injury to be sized for comparison by Dr. Richard Souviron, the chief forensic odontologist for the Miami-Dade medical examiner. Dr. Lowell Levine and Dr. Norman “Skip” Sperber independently performed evaluations of the materials. All agreed that the bite pattern left on the victim was of evidentiary value and showed class and individual characteristics of a double bitemark. They also agreed that Mr. Bundy’s teeth were unusual and distinctive and, more likely than not, had left the bitemark. A Tallahassee, Florida, circuit court judge heard evidence and ruled on the admissibility of bitemark evidence in the courts of the state of Florida. Drs. Souviron, Levine, and Sperber all testified at the evidentiary hearing. In a change of venue, the trial, State v. Bundy, was moved to Miami, Florida. The proceedings began in July of 1979. The defense called Dr. Duane T. Devore, a board-certified forensic odontologist who testified that

Bundy’s teeth were “not that unique” and produced preorthodontic treatment dental models of individuals that had similar lower anterior teeth arrangement. The prosecution pointed out that the models proffered were preorthodontic treatment models of 11- to 13-year-old individuals, none of whom had been in Tallahassee in January 1978. The prosecution’s experts testified that Bundy’s teeth (FigureÂ€1.8) were distinctive and demonstrated the common features between his teeth and the marks. Drs. Levine and Souviron and Dr. Homer Campbell testified for the prosecution. Mr. Bundy was convicted of the aggravated battery of three victims and the murder of the two Chi Omega sorority sisters, Lisa Levy and Margaret Bowman. He was sentenced to death on both counts of murder and life without parole on the aggravated batteries. Bundy appealed but the appeals court upheld the lower court’s decision [37]. In 1980, Mr. Bundy was again on trial for murder, this time of 12-year-old Kimberly Leach of Lake City, Florida. Following the trial, he was found guilty and again sentenced to death. The appeals on the Leach murder conviction were exhausted before those for the Florida State University students. At age 42, on January 24, 1989, Ted Bundy was executed in the electric chair for the murder of Kimberly Leach. Mr. Bundy had been a suspect in approximately 40 homicides of young females in the states of Washington, Oregon, Colorado, Utah, and Florida. The Bundy case was significant for forensic odontology, firmly establishing the admissibility of bitemark evidence in Florida and bringing bitemark evidence to national prominence. 1.3.6â•…Other Significant Cases 1.3.6.1â•…State v. Milone, 1973 (Illinois) Richard Milone was charged with the 1972 murder of Sally Kandel, who had a bitemark on her inner right thigh. He was tried and convicted in 1973 in a bench trial in DuPage County, Illinois. Three prosecution dental experts testified for the prosecution that Milone was the biter. Four dental experts for the defense disagreed in this now classic “battle of the experts” case. On appeal, three additional dental experts concurred with the original prosecution experts. The defense attempted to offer the testimony of an additional defense expert but was denied, bringing the total number of dental experts involved with this still controversial case to 11. Milone was convicted and his state appeal was denied in 1976. A federal appeal was denied in 1994. Part of the basis of the federal petition was the assertion that, at the original trial in 1973, “forensic odontology”

History of Bitemark Evidence

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Figure 1.8 An anterior view Ted Bundy’s teeth in 1979. Images of the varying faces of Bundy.

was in its infancy and unreliable; however, in the intervening years the “science of forensic odontology” had “advanced considerably” and now evidence was available that tended to exclude Milone and was “shown to match” another man. That other man was Richard Macek, a confessed and convicted serial killer. Macek had confessed on multiple occasions to the murder of Sally Kandel. Sources disagree on whether he later recanted those confessions. Macek committed suicide in his jail cell in 1987 [38,39]. The 1994 court affirmed the earlier state dismissal of Milone’s petition and included this statement regarding bitemark evidence in the case: “With respect to its probative value, while the science of forensic odontology might have been in its infancy at the time of trial, as Milone asserts, certainly there is some probative value to comparing an accused’s dentition to bite marks found on the victim” [39]. 1.3.6.2 Wilhoit v. State, 1991 (Oklahoma) Greg Wilhoit was accused of the 1985 murder of his former wife. Two prosecution dental experts testified that Wilhoit’s teeth matched a bitemark found on the

victim and that bacteria cultured from the bite area were unique to him. No defense dental expert testified at the original trial. Following Wilhoit’s conviction and death sentence, Dr. Thomas Krauss, who had been hired by the Wilhoit family but not used at trial, sent the case evidence to 11 other board-certified forensic dentists. Dr. Krauss and all 11 of the consulted forensic odontologists independently excluded Wilhoit as the creator of the bitemark on Mrs. Wilhoit. At an appellate pretrial hearing, Dr. Krauss and Dr. Richard Souviron testified that Wilhoit could be excluded as the biter. Both also stated that the bacterial evidence proffered by the prosecution dental experts, Drs. R. T. Glass and R. K. Montgomery, was flawed. They stated that more than 50% of the population would be expected to have the same types of oral bacteria reportedly found. Citing, in part, the defense attorney’s failure to investigate and utilize bitemark evidence, the appeal court ruled that his attorney was deficient and that Wilhoit had ineffective counsel. The prosecution decided not to retry him. Wilhoit was freed after spending more than 5 years in prison on death row [40].

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 1.9â•‡ Image of the Ancona breast bitemark compared with a polystyrene exemplar of Krone’s maxillary teeth (left). One odontologist’s tooth numbering (universal) scheme for the bitemarks (right).

1.3.6.3â•…People v. Moldowan and Cristini, 1991; People v. Moldowan, 2002; People v. Cristini, 2004 (Michigan) Following the 1990 kidnapping, assault, and rape of Maureen Fournier, she named five men who she said participated in the attack. Two of the men had allegedly bitten her. At trial in 1991, both Michael Cristini and Jeffrey Moldowan were convicted of the attacks. The convictions were based on the victim’s identifications and two forensic odontologists’ testimony that the bitemark associations were positive. Dr. Alan Warnick, a forensic odontologist, was a consultant to the Wayne County Medical Examiner’s Office. He was also a consultant to Macomb County, Monroe County, and the Michigan State Police. Dr. Warnick offered expert testimony that bitemarks on Fournier’s neck were consistent with dental impressions taken from Moldowan and that bitemarks on Fournier’s right arm and right side were consistent with Michael Cristini’s dentition. In describing his conclusions, Dr. Warnick testified that “chances are … 2.1 billion to 1 that another individual can make those same marks” (J.A. 2544) [41]. The other prosecution dental expert at the original trial testified in support of Dr. Warnick’s conclusions, but later recanted her testimony. In recanting, Dr. Pamela Hammel stated that “Dr. Warnick had been deceptive in order to mislead [her] into testifying in support of his conclusions” (J.A. 2568) [41]. On appeal in 1997, two dental experts, Drs. Homer Campbell and Richard Souviron, testified for the defense that both Moldowan and Cristini could be excluded as Fornier’s biters (R. Souviron, personal communication, 2008). Cristini and Moldowan were both later acquitted of the charges in separate trials [42]. 1.3.6.4â•…State v. Krone, 1992, 1995 (Arizona) Kimberley Ancona was attacked and killed in the early morning hours of December 29, 1991, at the CBS Lounge in Phoenix, where she worked as a bartender. A forensic

dentist called to the scene noted a probable bitemark on the decedent’s left breast (FigureÂ€1.9). He stated that the biter likely had “crooked” teeth. The investigation led police to a frequent customer of that bar, U.S. Postal worker Ray Krone, who was arrested and charged. Phoenix forensic odontologist Dr. John Piakis consulted first Dr. Norman “Skip” Sperber and later Dr. Ray Rawson. At trial, Drs. Piakis and Rawson testified for the prosecution. Dr. Piakis testified that Krone was the probable biter and Dr. Rawson that Krone was the biter with “reasonable medical certainty.” Dr. Sperber was not called by the prosecution. No dental expert testified for the defense at the original trial. Krone was convicted in the highly publicized “snaggletoothed killer” case and given a death sentence. In 1995 the Arizona Supreme Court reversed the conviction on procedural grounds and Krone was to have a new trial. Four forensic odontologists, including Dr. Sperber, independently excluded Krone as the person who made the bitemarks. Dr. Rawson again testified for the prosecution. Krone was found guilty in this retrial but sentenced to life in prison. As a result of the efforts of a relative and the Innocence Project, DNA evidence from the case was finally analyzed in 2002. The analysis not only excluded Krone but also resulted in a positive comparison to another man, coincidentally incarcerated in the same prison as Krone. At the time of the Ancona murder, Kenneth Phillips had lived very near the ABC Lounge and was a frequent customer. When questioned, Phillips confessed his involvement. Ray Krone was released and exonerated after spending 13 years in prison, including 3 years on death row. 1.3.6.5â•…State v. Brewer, 1995; Brewer v. State, 1998, 1999 (Mississippi) Kennedy Brewer was accused of the 1991 sexual assault and murder of 3-year-old Christine Jackson, the daughter of the girlfriend with whom he lived. Jackson’s body had been found in a nearby creek 3 days after her

History of Bitemark Evidence

disappearance. On the night in question, Christine Jackson’s mother was out and Brewer was her babysitter. The prosecution’s dental expert, Dr. Michael West, reported that he found 19 human bitemarks on Jackson’s body that were “peri-mortem in nature” and “were indeed and without doubt inflected [sic] by Kennedy Brewer” [43]. Dr. West later testified that “to a reasonable degree of medical certainty,” the teeth of Mr. Brewer made five of those marks and that it was “highly consistent and probable that the other 14 bite mark patterns were also inflicted by Brewer” [44]. The defense dental expert, Dr. Richard Souviron, testified that the injuries were not human bites at all: “There could be insect activity there. There could be fish activity or turtle activity or who–God knows what” [44]. Brewer was convicted and sentenced to death. All appeals were unsuccessful until extensive efforts were undertaken by the Innocence Project. Those efforts included a comprehensive review of all the patterned injury material by forensic odontologists Drs. Iain Pretty, David Senn, and David Sweet, who concluded— first independently and then jointly—that “none of the injuries seen in the photographic and video evidence are human bitemarks. Therefore, we are able to exclude human biting as a cause of these injuries” [45]. The effort also included an analysis of the aquatic animal population of the creek in which Jackson’s body had been found. Forensic entomologist Dr. John Wallace and Innocence Project attorney Vanessa Potkin collected crawfish from the creek and Dr. Wallace transported them back to his laboratory at Millersville University in Pennsylvania. In experiments using sacrificed pigs, he was able to observe the feeding habits of the crawfish and found that they created very similar patterned injuries to pigskin, an acceptable experimental analogue for human skin. In 2001, the Innocence Project was also successful in arranging a reanalysis of the victim’s vaginal swabs

15

taken at autopsy. The swabs contained semen with DNA profiles of two men. Neither profile was consistent with Kennedy Brewer but did point to another early suspect, Justin Albert Johnson. Confronted in 2008, Johnson confessed to sexually assaulting and killing Jackson and to earlier killing another girl of similar age in almost exactly the same manner. Dr. West had also testified in that earlier case that Levon Brooks had bitten the victim: “It could be no one else but Levon Brooks that bit this girl’s arm” [46]. Despite the 2001 DNA evidence excluding Brewer, he was not released on bail until 2007 and not exonerated until after Johnson’s confession in 2008, almost 13 years after Brewer’s conviction, most of which time he spent awaiting execution. 1.3.7â•…Cases in Modern Europe and the United Kingdom 1.3.7.1â•…Fredrik Fasting Torgersen, Oslo, Norway, 1957 Firemen responding to a basement fire on the night of December 7, 1957, found the body of Rigmor Johnsen. The discovery of a bitemark on the left breast of the sexually assaulted and strangled 16-year-old girl initiated the longest running bitemark case in history (FigureÂ€1.10). Fredrik Fasting Torgersen was arrested in the neighborhood that same night and became a suspect in the attack. Professor Ferdinand Strom collected the bitemark evidence from the victim and the suspect and he and Dr. Warhaug testified at the 1958 trial that Torgersen had made the bitemark. Torgersen was convicted and sentenced to life in prison. A 1958 appeal confirmed the conviction. Torgersen served 16 years and was released in 1974. He maintained his innocence throughout and repeatedly sought a new trial. He received assistance from a large team of supporters in Norway and there were multiple efforts before

Figure 1.10â•‡ Rigmor Johnsen prior to autopsy (left). The only scaled image of the patterned injury to Johnsen’s left breast (right).

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Supreme Court committees and the Commission for Criminal Case Review to procure a new trial. Over the years, many forensic odontologists have reviewed the evidence in this case and written reports. Those concluding that Torgersen was the biter include Drs. Ferdinand Strom, Jens Waerhaug, and Tore Solheim of Norway; Dr. Gisle Bang of Sweden; and Drs. Gordon MacDonald and David Whittaker of the United Kingdom. Forensic dentists excluding Torgersen as the biter include Drs. Marden Alder, Michael Bowers, David Senn, and Paul Stimson, all of the United States. At the time of the writing of this chapter, there is still an ongoing effort to secure a new trial for Torgersen, 52 years after his conviction in 1958 (E. Moss, personal communication, 2010). 1.3.7.2â•…Gordon Hay, Biggar, Scotland, 1967 Fifteen-year-old Linda Peacock was found murdered in a cemetery in Biggar, Scotland, on August 6, 1967. She had been strangled and there was a suspected bitemark on her right breast (FigureÂ€1.11). Gordon Hay was a detainee at a nearby school for troubled boys and became one of 29 persons initially considered to be viable suspects. Dr. Warren Harvey had examined many Biggar residents, including the boys from the Loaningdale School. Five of the boys were selected for additional scrutiny but only Hay showed unusual pits at the tips of the cusps of the canine teeth. Those pits, along with other features, were shown to be consistent with features seen in the bitemark. Dr. Harvey consulted with Professor Keith Simpson, a well known forensic pathologist with bitemark case experience. Dr. Harvey and his associates made a remarkably detailed study of the mark, the suspects, and the frequency of occurrence of pits at the tips of canine cusps. Dr. Harvey and Professor Simpson testified at trial that

Hay was the biter. Gordon Hay was convicted and, because he was a minor, sentenced to serve a term of undetermined length “at Her Majesty’s pleasure” [47]. 1.3.8â•…Cases in Modern Africa 1.3.8.1â•…State v. Shabangu, 1998 In the High Court of South Africa, before the Honorable Justice Curlewis, the case involved a piece of cheese with very clear teeth marks found next to the body of an elderly woman who had been raped and murdered. Dr. Piet van Niekerk, Professor Vince Phillips, and Professor Herman Bernitz piloted the forensic dental evidence. All three concurred that Shabangu had indeed inflicted the bitemark in the cheese, but could not convince Justice Curlewis. At issue were these points (H. Bernitz, personal communication, 2010): • Which dental features are common, uncommon, and very uncommon within the relevant populations • The need to refine pattern association and explain how warping, shrinkage, and distortion do not affect pattern association analysis of bitemarks • The use of metric analysis in bitemark cases • The use of microscopic analysis in individualizing features within the bitemarks • The application of all the preceding in skin bitemarks, which are very much more challenging 1.3.8.2â•…State v. Nxele, 1999 This case was heard in the Pietermaritzburg High Court. Microscopic analysis of bitemarks was performed for the first time. A piece of cheese with very clear bitemarks was analyzed macroscopically and the analysis tested with a DMC comparison microscope used for analyzing

Figure 1.11â•‡ Crime scene in Biggar, Scotland, 1967 (left). Strangulation marks on neck and bitemark on right breast (center). Detail of bitemark on Peacock’s right breast (right).

History of Bitemark Evidence

firearm barrels and bullets. The sledge/scratch marks were matched to a point of absolute certainty because the suspect had very characteristic incisal patterns on his anterior central teeth. Senior superintendent Burgert Kloppers, a ballistics expert at Silverton Forensic Labor atory, testified; his many years of court experience enhanced the ability of forensic odontologists to present evidence in this court case correctly. Since his inclusion on the bitemark team, no evidence has been submitted without his corroboration. “This partnership I believe has been the cornerstone of our success and should be practiced more regularly by our colleagues around the globe” (H. Bernitz, personal communication, 2010). 1.3.8.3 Vierfontein, Free State, 2002 A farmer and his wife were attacked and murdered on their small holding in the Vierfontein area of the Free State. The woman was also raped. Following a thorough forensic investigation, it became clear that the perpetrators had used gloves during the robbery and had used condoms during the rape. This created a situation where very little evidence was present at the crime scene. Police found a half-eaten apple in the driveway. The apple had a very characteristic dental arch pattern profile on the surface skin where the incisal edges of the teeth had entered. The pattern could be accurately matched to the suspect’s dentition with a high degree of certainty. In this case, both macroscopic and microscopic analysis confirmed the high degree of concordance present (H. Bernitz, personal communication, 2010). 1.3.9 Cases in Modern Australia 1.3.9.1 Ipswich, Queensland, 1973 At dawn on Saturday, April 14, 1973, 17-month-old Deidre Kennedy’s body was found tossed onto the roof of a toilet block, 500 m from the Kennedy family’s twobedroom flat in Ipswich. The infant had been abducted sometime after 10 p.m. the previous night while sleeping beside her sister, Stephanie. She had been sexually assaulted and strangled. Three bitemarks were identified on the outside of Deidre’s left leg. The killer had dressed the tiny girl in a woman’s half-slip, panties, and step-ins, all stolen from a clothesline next door. The case was vigorously investigated but, one by one, the suspects were cleared and the case went cold. Then, in 1984, Raymond John Carroll came under suspicion in a case similar to the Kennedy murder. Hair samples and dental impressions were collected with Carroll’s consent. Investigators were told by forensic odontologist Cornel Romaniuk, who had examined the

17

Kennedy evidence, “This is your killer” [48]. At Carroll’s trial in February 1985, dental evidence was given by Romaniuk and two other odontologists, Kenneth Brown and Bernard Sims. Carroll was convicted and sentenced to life imprisonment. Brown later stated that he was “very, very confident” that Carroll had made the bitemarks on Kennedy’s body. Nevertheless a court of criminal appeals overturned the verdict, citing that the odontology evidence was “unsafe and unsatisfactory.” After the reversal, further evidence was found, but Carroll could not be charged again with the same murder. He was charged instead with perjury—that he had lied at his murder trial when he said he had not killed Kennedy. This second jury found him guilty of perjury in 2000. That conviction, however, was also overturned on appeal. The high court also rejected an application from the Queensland government to annul the appeals court decision [49]. A single pubic hair found on Deidre Kennedy’s body could have been critical evidence. Unfortunately, the hair failed to yield a DNA profile, reportedly because the evidence was destroyed by a “laboratory bungle” [48]. Citing Australia’s double jeopardy rule, the high court has held that Carroll could never again face a criminal trial with regard to Kennedy’s murder. 1.3.9.2 Darwin, Northern Territory, 1986 A Darwin woman left the Victoria Hotel after an argument with her boyfriend, Dean Teau. After a side trip to a discotheque, she decided to return to her hotel. A young man whose advances she had rejected followed her there and attacked and raped her. After the attack, she felt ill and, unbelievably, the man offered to take her to a hospital. He hailed a taxi, and both were in the taxi when Teau arrived at the scene. Screaming that she had been raped, Teau pulled the assailant from the taxi and held him in a headlock, but he escaped by severely biting Teau on the chest. Michael Anthony Lewis was later arrested and accused of the attack. He consented to the gathering of dental evidence by Dr. J. R. Plummer, who consulted with Dr. B. Sims. Both gave evidence at trial that the wound on Teau’s chest was a bitemark made by Lewis’s teeth. Dr. S. D. Dalitz testified for the defense. All agreed that there were bruises left by five lower teeth and no marks from upper teeth. Lewis was tried and convicted of rape on October 24, 1986. The judge in the original trial stated in part that “the evidence clearly established that the study of the characteristics of human bite marks and consequent identification of persons responsible

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

for such marks fall within a field of expertise, and the witnesses called for the Crown (no expert was called for the defense) are all experts in that field.” On appeal, the petition was granted and the conviction was quashed. One appellate judge noted that “there is a very considerable risk that the jury were awed by Mr. Sims’ credentials and the confident manner in which he expressed his conclusion, notwithstanding that its probative value in linking the appellant to the rape was not demonstrated to be great” [50].

1.4â•…Forensic Odontology Organizations 1.4.1â•…International Organization for Forensic Odontostomatology (IOFOS) This international organization has 18 component societies or associations. The IOFOS publishes newsletters three times each year and has also published the Journal of Forensic Odontostomatology twice annually since June 1983. In 1987 the journal became the official publication of the IOFOS. Starting in 2008, this refereed, fully indexed journal ceased its print version and began publishing the journal in an electronic version only. The journal is available without subscription on the organization’s Web site at http://www.odont.uio.no/foreninger/iofos/. Member societies and associations include: American Society of Forensic Odontology Australian Society of Forensic Odontology Austrian Society of Forensic Medicine (OGGM) British Association for Forensic Odontology Croatian Association of Forensic Stomatologists Arbeitskreis für Forensische Odontostomatologieâ•‰ —Germany Danish Society of Forensic Odontology Finnish Association of Forensic Odontology Flemish Association of Dental Experts Forensische Zahnärzte der Schweiz (FOCH)â•‰ —Switzerland Association Francaise d’Identification Odontologic (AFIO) Icelandic Society of Forensic Odontology Japanese Society of Forensic Odontology Korean Committee of Forensic Odontology/Dental Jurisprudence Nederlands Forensische Medische Genootscap New Zealand Society of Forensic Odontology South African Society for Forensic OdontoÂ� stomatology Swedish Society of Forensic Odontology

The IOFOS also maintains a list of worldwide forensic odontology contacts known as the “Burgmann list.” Although not necessarily current, it lists forensic odontologists from 123 countries worldwide. 1.4.2â•…The Odontology Section of the American Academy of Forensic Sciences (AAFS) In 1970 forensic odontology was recognized by the forensic science community as a specialty of forensic science with the formation of the odontology section of the AAFS. Dr. Lowell Levine served as the first section chairman and Dr. Edward Woolridge was the first section secretary. 1.4.3â•…The American Society of Forensic Odontology (ASFO) The AFSO was also formed in 1970. Col. Robert Boyers and others from the faculty of the Armed Forces Institute of Pathology (AFIP) forensic odontology course were instrumental in the organizational effort. From those beginnings, the ASFO has grown into the largest single forensic odontology organization in the world (it is a component of the IOFOS), offering annual educational programs at its meeting in conjunction with the annual AAFS meetings. It also publishes the Manual of Forensic Odontology, now in its fourth edition, with a fifth edition planned. 1.4.4â•…Canadian Society of Forensic Science (CSFS), Odontology Section That seminal year of 1970 also included the merger of the Canadian Association of Forensic Odontology with the Canadian Society of Forensic Odontology. This group became the odontology section of the CSFS in 1972. 1.4.5â•…American Board of Forensic Odontology In 1976, with the initial sponsorship of the American Academy of Forensic Sciences (AAFS) and the encouragement and assistance of the National Association of Medical Examiners (NAME), the American Board of Forensic Odontology (ABFO) was formed. The charter members of the ABFO were Drs. Edward Woolridge, Richard Souviron, Curtis Mertz, Arthur Goldman, Gerald Vale, Stanley Schwartz, Lowell Levine, Robert Dorion, Paul Stimson, David Scott, Manuel Maslansky, and George Ward. Dr. Curtis Mertz served as the ABFO’s first president from 1976 until 1978.

History of Bitemark Evidence

The ABFO was organized to provide, in the interest of the public and for the advancement of the science, a program of certification in forensic odontology. The objective of the board is to establish, enhance, and revise, as necessary, standards of qualification for those who practice forensic odontology and to certify as qualified specialists those applicants who comply with the requirements of the board. The ABFO maintains standards and guidelines relating to bitemark evidence. These can be found in the ABFO Diplomates’ Reference Manual, which is updated and posted on the organization’s Web site at www.abfo. org. The standards address analytical methods and bitemark terminology. Standards for analytical methods: 1. All diplomates of the American Board of Forensic Odontology are responsible for being familiar with the most common analytical methods and should utilize appropriate analytical methods. 2. A list of all the evidence analyzed and the specific analytical procedures should be included in the body of the final report. All available evidence associated with the bitemark must be reviewed prior to rendering an expert opinion. 3. Any new analytical methods not listed in the previously described list of analytical methods should be explained in the body of the report. New analytical methods should be scientifically sound and verifiable by other forensic experts. New analytical methods should, if possible, be substantiated with the use of one or more of the accepted techniques listed in these guidelines. Standards for terminology: 1. Terms assuring unconditional identification of a perpetrator, or without doubt, are not sanctioned as a final conclusion. 2. Terms used in a different manner from the recommended guidelines should be explained in the body of a report or in testimony. 3. All boarded forensic odontologists are responsible for being familiar with the standards set forth in this document. The guidelines are extensive and periodically updated. They can be viewed on the Web site.

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1.5â•…History of Bitemark Education in North America 1.5.1â•…A rmed Forces Institute of Pathology (AFIP) In 1962 a course in forensic odontology was implemented by the Armed Forces Institute of Pathology (AFIP) in Washington, D.C. Drs. Albert Dahlberg, Louis Hansen, John Salley, Viken Sassouni, and David Scott gave presentations in the initial 4-day course. Soon the course became an annual event and the 2010 course was billed as the 46th Annual Forensic Dental Identification and Emerging Technologies course. The week-long course includes education in all phases of forensic odontology including bitemarks. The 2010 course directors were Duane R. Schafer, Capt., DC, USN, and Christopher G. Fielding, Col., DC. 1.5.2â•…McGill University and the Laboratoire de Sciences Judiciaires et de Médecine Légale (LSJML) Believed to be the first North American forensic laboratory formed under legislative authority, the laboratory in Montreal known today as the Laboratoire de Sciences Judiciaires et de Médecine Légale was founded in Quebec in 1914. Dr. Robert B. J. Dorion has been the director of forensic dentistry since 1973. As a member of McGill University’s faculty of dentistry, Dr. Dorion has also been the director of a combined distance learning and on-site course since 2004. The course runs from September to August of the following year. Theory, readings, assignments, and weekly live chats between participants and the course director take place over 24 weeks. Two additional weeks (10 days) are spent at the aforementioned forensic laboratory for practical hands-on training in May (identification) and in August (human bitemark analysis with a gold standard). Successful completion of the program leads to a certificate in forensic dentistry. Past graduates have traveled from as far away as Israel and New Zealand. Program information is available at http://www.mcgill.ca/dentistry/conted/forensic. 1.5.3â•…University of Texas Health Science Center at San Antonio Dental School In 1979 at the Dental School of the University of Texas Health Science Center in San Antonio (UTHSCSA), Dr. James A. Cottone, assisted by Dr. S. Miles Standish, directed a symposium on forensic dentistry. Initially an annual symposium, the Southwest Symposium on Forensic Dentistry changed to biannual sessions in 1984.

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

The 2010 week-long course was the 19th symposium. Dr. Cottone was the symposium director from 1979 to 1994, Dr. Marden E. Alder directed it from 1996 to 1998, and Dr. David R. Senn became director in 2000. Codirectors have included Drs. Paul G. Stimson, John D. McDowell, Paula C. Brumit, and Bruce A. Schrader. Dr. Stimson has been on the symposium faculty since the beginning in 1979 and has been a codirector since 1996. In 1999, UTHSCSA opened the Center for Education and Research in Forensics (CERF) and accepted the first fellow in forensic odontology, Dr. John Williams of Minneapolis, Minnesota. Through 2010, 38 dentists have completed the fellowship and nine of those former fellows have become board certified by the ABFO. Dr. David R. Senn directs CERF and the fellowship in forensic odontology. 1.5.4 Bureau of Legal Dentistry (BOLD) In 1997 in Vancouver, British Columbia, Canada, the Bureau of Legal Dentistry (BOLD) began full-time operation in forensic odontology research, casework, and undergraduate and graduate teaching. BOLD was made possible by contributions from the provincial government and with support from the Faculty of Dentistry of the University of British Columbia. Dr. David J. Sweet, O.C., has been the director of BOLD since its creation. 1.5.5 Other Courses Northwestern University Dental School, Chicago, Illinois (1891–2001), sponsored courses in bitemark analysis before the school closed its doors in 2001. The University of Detroit (Michigan) Mercy School of Dentistry offers annual courses in forensic odontology that include education in bitemark recognition and analysis. Dr. Allan Warnick is the course director.

1.6 Challenges to the Legitimacy of Bitemark Evidence Investigators from both outside and within forensic odontology have challenged the reliability and accuracy of bitemark analysis. Most of these challenges cite the paucity of scientific research into the bases for the discipline. The specific issues include questions about (1) the uniqueness of the anterior human dentition, (2) human skin as a bite registration medium, (3) the scientific bases for analytical methods, (4) management of observer

effects and bias, and (5) the levels of conclusions possible for specific types of cases. 1.6.1 Bitemark Evidence Controversies Many early and modern forensic odontologists have urged that bitemark evidence be viewed and reported with caution. The sensational nature of the cases involving bitemarks may have contributed to the acceptance of the evidence in courts before the science supporting it was fully developed. Many of the cases described previously and in the following chapters illustrate the need for that caution. Later chapters will also explore the root causes of and offer strategies for avoiding or minimizing future controversies. 1.6.2 National Academy of Sciences 2009 Report Beginning in April 2007, the Committee on Identifying the Needs of the Forensic Science Community reviewed and investigated many facets of forensic science, including forensic odontology. The reported aim of the committee was “to chart an agenda for progress in the forensic science community and its scientific disciplines.” In February 2009, the committee released its report, titled Strengthening Forensic Science in the United States: A Path Forward. Chapter 5, “Descriptions of Some Forensic Science Disciplines,” includes a section titled Forensic Odontology. With the exception of the first paragraph, the entire section deals with problems associated with bitemark analysis and bitemark evidence. In the summary, the report states that “although the majority of forensic odontologists are satisfied that bite marks can demonstrate sufficient detail for positive identification, no scientific studies support this assessment, and no large population studies have been conducted.” The report also says, “In numerous instances, experts diverge widely in their evaluations of the same bite mark evidence. The committee received no evidence of an existing scientific basis for identifying an individual to the exclusion of all others.” The committee closed the section on forensic odontology by stating that “some research is warranted in order to identify the circumstances within which the methods of forensic odontology can provide probative value” [51]. This report is widely viewed as a “wake-up call” to practitioners of forensic odontology to take steps to firmly establish the scientific bases for bitemark analysis and bitemark evidence.

History of Bitemark Evidence

1.7 Perspective on the Relationship between the Past and Future of Bitemark Evidence “Those who cannot remember the past are condemned to repeat it” [52]. This often misquoted George Santayana maxim is a wise warning to practitioners of bitemark analysis. To ignore the warning and to fail to study the history of bitemark evidence is to risk repeating earlier errors of omission and commission. The acceptance (some would say premature acceptance) of bitemark evidence in the Doyle and Marx cases led to the wide use and misuse of bitemark evidence by forensic dentists and others. That so much is heard and written about the relatively few problem bitemark cases and almost nothing of the many cases that were properly handled is unfortunate. However unfortunate that may be, forensic dentists are not absolved of the responsibility to study and understand those cases so that errors can be minimized in the present, thereby improving the discipline in the future. Forensic odontologists must engage in continuous research to develop and expand the scientific bases of the discipline. The examination of current practices and theories and the rejection of those shown to be erroneous or inadequate are mandatory. Forensic odontology’s certifying bodies must effectively test and periodically retest their certified members for proficiency in bitemark analysis. It is the opinion of this author that bitemark evidence is too potentially valuable to our systems of justice to be discounted or abandoned. Such evidence offers useful information and specific advantages, especially in certain types of cases.

Acknowledgments Information on the African cases was excerpted from material generously provided by Professor Herman Bernitz, School of Dentistry, University of Pretoria, Pretoria, South Africa. He is also president of the IOFOS. Professor Bernitz added (personal communication 2010): We are now regularly required to give expert witness testimony in bite mark cases around South Africa, which we do with confidence in the knowledge that we understand the dynamics of biting, the effects of warping, shrinkage and distortion, the shortfalls of metric analysis and the reliability of pattern association. It is important to realize that we are selective as to which skin bite mark cases we choose to analyze. Not all bite

21 marks are suitable for analysis: We only analyze skin bite marks where individual dental features can be clearly identified.

Information on Australian cases was gleaned from material suggested by Dr. Anthony J. Hill, president of the Australian Society of Forensic Odontology.

References 1. Jacobs, R. A., ed. 2001. Animal and human bite wounds. In General problems in infectious diseases. Current medical diagnosis and treatment, 40th ed., ed. J. L. M. Tierney et al. New York: Lange Medical Books/McGraw–Hill. 2. Prinz, H. 1915. A contribution to the tooth in its relation to forensic medicine. British Dental Journal 36 (14): 383–386. 3. Harvey, W. 1976. Dental identification and forensic odontology. London: Kimpton (xii, 188 pp., leaves of plates). 4. Keiser-Nielsen, S. 1992. Teeth that told, 95. Odense, Denmark: Odense University Press. 5. Keiser-Nielsen, S. 1950. [Forensic odontology; case report; bite marks]. Tandlaegebladet 54 (7): 436–442. 6. Merciolle. 1891. Appreciation de l’examen medicolegale de la dentition dans les questions d’identite. Lyon: Universite de Lyon. 7. Bowers, C. M. 2004. Forensic dental evidence: An investigator’s handbook, 1st ed. San Diego, CA: Elsevier Academic Press, 211 pp. 8. Whittaker, D., and MacDonald, D. G. 1989. A color atlas of forensic dentistry, 134. London: Wolfe Publishing Ltd. 9. Sperber, N. 1998. A bite mark on the weather stripping of a pickup truck leads to a rape conviction. Oral presentation, American Academy of Forensic Sciences. San Francisco. 10. Dorion, R. B. J. 2005. Bitemark evidence. New York: Marcel Dekker. 11. Burton, R. F., and Kama Shastra Society of London and Benares. 1893. The kama sutra of Vatsyayana. London: [n.p.], 181 pp. 12. Hermann, P., and P. G. Edwards. 1978. Orkneyinga saga: The history of the earls of Orkney. London: Hogarth Press, 223 pp. ([2] leaves of plates). 13. Holt, J. K. 1980. Identification from bite marks. Journal of Forensic Science Society 20 (4): 243–246. 14. Lower, M. A. 1845. The curiosities of heraldry. London: J. R. Smith (xvi, 319 pp.). 15. Taylor and Hare. 1847. Sigilla antiqua. Engravings from ancient seals attached to deeds and charters in the muniment room of Sir Thomas Hare. Stowe-Bardolph: priv. print (1 p.l., 14 l). 16. Webster, N., and N. Porter. 1913. Webster’s revised unabridged dictionary of the English language; the dictionary proper being the authentic ed. of Webster’s international dictionary of 1890. Springfield, MA: G. & C. Merriam Company, 2026 pp.

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17. Coke, E., and T. Littleton. 1628. The first part of the institutes of the lawes of England, or, a commentarie upon Littleton, not the name of a lawyer onely, but of the law it selfe: haec ego grandaeuus posui tibi candide lector. London: printed [by A. Islip] for the Societie of Stationers ([7], 395, [1] leaves, [1] folded leaf of plates). 18. Rothwell, B. R. 1995. Bite marks in forensic dentistry: A review of legal, scientific issues. Journal of American Dental Association 126 (2): 223–232. 19. Van der Zee, J. 1985. Bound over: Indentured servitude and American conscience. New York: Simon and Schuster, 382 pp. 20. Boyer, P. S., S. Nissenbaum, and United States Work Projects Administration. 1977. The Salem witchcraft papers: Verbatim transcripts of the legal documents of the Salem witchcraft outbreak of 1692. New York: Da Capo Press (3 v., 1070 pp.). 21. Calef, R. 1700. More wonders of the invisible world. London: Printed for N. Hillar and J. Collyer (6 p. l, 156 pp.). 22. Rhodes, H. T. F. 1937. The criminals we deserve; a survey of some aspects of crime in the modern world. 1937, New York: Oxford University Press (xi, 257 pp.). 23. Strom, F. 1963. Investigation of bite-marks. Journal of Dental Research 42 (1): 312–316. 24. Sorup, A. 1924. Odontoskopie: Ein betrag zur gerichtlichen. Medizin Vjschr Zahnheilk 40:385–388. 25. Pierce, L. J., D. J. Strickland, and E. S. Smith. 1990. The case of Ohio v. Robinson. An 1870 bite mark case. American Journal of Forensic Medical Pathology 11 (2): 171–177. 26. The murder! A terrible crime. In Richland Shield and Banner, 1870: Mansfield, Ohio. 27. Keyes, F. 1925. Teeth marks on the skin as evidence in establishing identity. Dental Cosmos 67:3. 28. Simpson, K. 1947. The Heath case. Police Journal 2:266. 29. Simpson, K. 1979. Forty years of murder: An autobiography, 1st U.S. ed. New York: Scribner (328 pp. [12] leaves of plates). 30. Simpson, K. 1951. Dental evidence in the reconstruction of crime. British Dental Journal 91 (9): 229–237. 31. Sykora, O. 1987. How a munched apple gave a robber away. American Academy of History of Dentistry 35 (1): 64–65. 32. Doyle v. State, 159 Tex. C.R. 310, 263 S.W.2d 779. 1954.

33. Furness, J. 1968. A new method for the identification of teeth marks in cases of assault and homicide. British Dental Journal 124 (6): 261–267. 34. Swann, G. C. 1974. The Wayne Boden murders. International Journal of Forensic Dentistry 2 (4): 34–42. 35. People v. Johnson, 8 Ill. App.3d 457, 289 N.E.2d 772 (Nov. 16, 1972). 1972. 36. People v. Marx, 54 Cal. App.3d 100, 126 Cal. Rptr. 350. 1975. 37. Bundy v. State, 455 So 2d 330 (Fla. 1984):349. 1984. 38. People v. Milone, 43 Ill. App.3d 385, 356 N.E.2d 531. 1976. 39. Milone v. Camp, 22 F.3d 693 (7th Cir. 1994), 698 1994. 40. Wilhoit v. State, 809 P.2d 1322 (Ct. of Crim. App. of Okla). 1991. 41. Moldowan v. City of Warren, 578 F.3d 351 (6th Cir., 2009). 2009. 42. People v. Moldowan, 466 Mich 862; 643 NW2d 570 (2002). 2002. 43. West, M. H. 1992. Forensic report: Examination of Cristine Jackson, May 14, 1992. 44. Brewer v. State, 819 So. 2d 1169 (Miss. 2002). 2002. 45. Pretty, I., D. Senn, and D. Sweet. 2007. Review of patterned injuries in State of Mississippi v. Kennedy Brewer. 46. Brooks v. State, 748 So. 2d 736 (Miss. 1999). 1999. 47. Harvey, W. et al. 1968. The Biggar murder. Dental, medical, police and legal aspects of a case “in some ways unique, difficult and puzzling.” Journal of Forensic Science Society 8 (4): 157–219. 48. Walker, J. 2003. A review of the Deidre Kennedy murder case. The Weekend Australian. http://www.ourcivilisation. com/signs/deidre.htm 49. Roberts, G. 2002. Double Jeopardy in the Dock. Sydney Morning Herald (smh.com.au). 50. Michael Anthony Lewis v. the Queen, No. 5 of 1986, S.C.C.Nos.91-92. 1986, Supreme Court of the Northern Territory of Australia. 51. National Research Council (U.S.) Committee on Identifying the Needs of the Forensic Science CommunÂ� ity, National Research Council (U.S.) Committee on Science Technology and Law Policy and Global Affairs, and National Research Council (U.S.) Committee on Applied and Theoretical Statistics. 2009. Strengthening forensic science in the United States: A path forward. Washington, D.C.: National Academies Press, 328 pp. 52. Santayana, G. 1905. The life of reason or, the phases of human progress. New York: C. Scribner’s Sons (5 v.).

Bitemark Recognition

II

The Role of Health Professionals in Diagnosing Patterned Injuries from Birth to Death

2

John D. McDowell Contents 2.1 Overview of Biting Associated with Domestic Violence 2.2 Child Abuse 2.3 Intimate Partner Abuse 2.4 Bitemarks in Elder Abuse 2.5 Conclusion References

2.1â•…Overview of Biting Associated with Domestic Violence

25 25 27 28 29 30

all cases [2,3]. Witnessing violence is a risk factor for long-term mental and physical health, including being a victim of abuse or perpetrating abuse [4,5]. Without intervention, inflicted trauma tends to persist throughout the time that families live together. Some abused children learn that violent behavior is a way of accomplishing short- or long-term goals. Abused children might grow into abused or abusive adults. This violent learned behavior can lead to dysfunctional and abusive relationships that may continue for years, even beyond the seventh and eighth decades of life. Regardless of age or ability, the individual within a violent relationship can be the recipient of any number of different injuries. These include shooting, stabbing, hitting, slapping, kicking, pushing, and biting. Biting as a means of inflicting injury has been reported in nearly every developed country. Excellent articles on recording and analyzing bitemark evidence originate from the United States, Canada, all of the countries within the United Kingdom, India, Russia, and Germany, to name a few [6–14]. Bitemark injuries appear to be a universal problem.

North Americans and Europeans continue to report that violence in society is one of their main concerns, and domestic violence is continuing to increase in both locations. Whereas the home should be a safe haven from violence, the family is anything but safe for many individuals. Children, women, the disabled, and the elderly are more likely to be victims of intentional trauma within their own homes than they are at any other single location. Most domestic violence goes unreported and therefore undocumented. Citing the work of Jaden and Thoennes [1], the National Center for Injury Prevention and Control, a division of the Centers for Disease Control and Prevention, has reported that in the United States (1) approximately 1.5 million women and 0.8 million men are raped and/or physically assaulted by an intimate partner each year, (2) more than 500,000 women injured during IPV (intimate partner violence) require medical treatment, and (3) one in four women has been physically assaulted or raped by an intimate partner, and one in fourteen men has reported assault or rape by an intimate partner. Because intentionally inflicted trauma can be perpetrated upon any member of the family, it is difficult to separate one form of domestic violence from another. Battered women are arguably the most common subset of domestic violence victims within dysfunctional families. Not surprisingly, a battered woman is at greater risk of generating a battered child. A child reared within a loving, supportive, nonviolent home is less likely to become an abuser. Concurrence rates of intimate partner abuse and child abuse (an abused mother with an abused child or children) have been reported approximating 50% of

2.2â•…Child Abuse Child abuse is a major public health threat in North America. Most reporting agencies indicate that approximately 1 million American children suffer nonfatal, intentionally inflicted physical injuries during any given year. For the past several years, the National Center for Injury Prevention and Control has consistently reported that homicide is the fourth leading cause of death in children between the ages of 1 and 10 years and the third leading cause of death for children aged 10–14. Approximately 1,200 children die in the United States 25

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 2.1 Bitemark on cheek and arm.

every year from abuse and neglect; many die because of physical injuries inflicted by one or both parents. Among many other forms of trauma, evidence of biting is frequently seen in fatal and nonfatal child abuse cases. Bitemarks can take many forms and can be seen in various stages of healing in the living abused child. Figure 2.1 (left) reveals a recent cheek bitemark on a 3-year-old African American. According to the mother, the child was left in the care of the boyfriend for a brief period. Upon her return, the child had been badly burned by water immersion. The mother immediately noticed the cheek injury and made sure that medical personnel attending to the child’s burns photographed the bitemark. The bite is reportedly less than 2 hours old. Figures 2.1 (right) and 2.2 (left) demonstrate two separate bitemarks in a child abuse victim with significant head injuries. Figure 2.1 (right) shows a bitemark on the child’s left upper arm and attests to the importance of

making several photographs of the bitemark on a curved surface. The photograph should include as much of the dental arches as possible in one frame while remaining perpendicular to the majority of the bitemark. In this example, the canine-premolar region is recorded but the incisor regions are unclear. Figure 2.2 (left) illustrates the proper photographic technique for localizing and orienting the bitemark with the American Board of Forensic Odontology (ABFO) no. 2 scale. It is also recommended that additional photographs be taken from a more distant vantage point without scale and with the removal of any materials or equipment. Although some bitemarks associated with child abuse may be reasonably clear, more commonly the diagnosed bitemark is a diffuse ecchymosis that may initially appear to be of little evidentiary value. Notwithstanding the limitations rightfully associated with these diffuse injuries, valuable evidence may also be associated with these marks.

Figure 2.2 Bitemark on the upper chest (left) and diffuse bitemark on the abdomen (right).

The Role of Health Professionals in Diagnosing Patterned Injuries from Birth to Death

27

Figure 2.3 Bite on the mons pubis and on the back.

Figure 2.2 (right) shows a diffuse abdominal bitemark on a 4-year-old homicide victim. There are few individual dental characteristics detected within the class characteristics. However, the bitemark may contain significant evidence in the form of saliva from which the perpetrator’s DNA can be recovered. Color and black-and-white photographs are not the only bitemark-recording media. Bitemarks and other healing pattern injuries might be recorded by imaging techniques not commonly available to medical emergency personnel. Infrared, ultraviolet, and alternate light recording systems might be available through law enforcement, forensic labs, or medical examiner offices. These imaging systems record beyond the visual light spectrum. It is also important to note that the ABFO no. 2 scale (available through Lightning Powder Company) in Figures 2.1 (right) and 2.2 (left) references the bitemark metrically. Whether recorded on film or digitally [15], an additional gray-scale reference is present for density reproduction of the captured image. The less acceptable, one-dimensional ruler in Figure 2.2 (right) also shows a Kodak color control patch, which is used by some photographers to verify color accuracy.

2.3 Intimate Partner Abuse Intimate partner abuse (also called spouse or spousal abuse) is the commonest form of domestic violence. There has been much debate over which gender is more likely to commit abuse or which member in the partnership is more likely to be abused. Historically, most authors have reported that women are more frequently recipients of abuse and receive the more severe injuries. However, several recent studies,

including meta-analyses, conclude that men are just as likely to be abused as women [16–21]. A review of the behavioral science literature indicates that some studies report that women were more likely than men to commit acts of aggression and more frequently use aggressive acts [22–26]. It does not matter whether the man or the woman is more likely to be physically aggressive; that both may commit acts of violence against an intimate partner is important. This includes biting [27–29]. As in child abuse, bitemarks associated with spouse abuse may be found on any part of the body. Figure 2.3 (left) reveals an ill-defined bitemark on the mons pubis. After other physical evidence was collected and the area was photographed extensively under various lighting conditions, the pubic hair was shaved to demonstrate the diffuse bruising more clearly. The maxillary canines produced the prominent contusions. When detected by health care providers, law enforcement personnel, or others, bitemarks should be treated and documented in accordance with standard institutional practices. Additionally, any forensic evidence should be recovered including, when indicated, salivary evidence from the wounds. Photography remains a significant means of evidence collection and preservation. When curved surfaces like breast tissue or extremities are photographed, it is often necessary to take photographs in two or more planes. Figure 2.4 demonstrates one technique for aligning the film plane with the bitemarks. Figure 2.3 (right) shows a bitemark on the woman’s upper back. Note how the bitemark can be recorded in one photographic frame. Depending on the biter’s force and movement, avulsive injuries can occur. Bitemark analyses are often more complex when tissue has been distorted or removed. Medical intervention, including suturing and bandaging, inflammation, and the healing process itself,

28

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

2.4â•…Bitemarks in Elder Abuse

Figure 2.4â•‡ Photographic angulation.

may compound the problem. FigureÂ€ 2.5 (left) displays a bitemark on an abused woman’s upper right chest. Although the victim was very specific on the perpetrator’s identity and timing of the event, the bitemark analysis could not provide identity confirmation. FigureÂ€2.5 (right) depicts a nose bitemark produced during a violent struggle. The bite was so deep that the tip of the nose was nearly lost in transport. FigureÂ€ 2.6 (left) demonstrates a neck bitemark inflicted during domestic violence. Several hours after the assault, the woman presented to the emergency department for treatment of other injuries. When asked about the neck bruise, the woman admitted that she had been bitten. Individual teeth marks cannot be identified within the inflammation; however, serial photographs should be taken with various films and light sources.

Figure 2.5â•‡ Bitemark on the upper right chest and nose.

The 2000 census revealed that more than 20% of the U.S. population was 65 years of age or older. Most of these individuals resided in homes where the quality of life exceeded that of previous generations. As they age, some will remain in good health; others will develop chronic and disabling diseases that limit their daily activity. A few will eventually become totally dependent on others. Unfortunately, some will be subjected to abuse and neglect. A recent estimate indicates that nearly 500,000 elderly persons annually experienced abuse, neglect, or both in the domestic setting [30]. In the United States, self-neglect, the condition where an elderly, self-sufficient person loses autonomy, is prevalent. Another common form of neglect is unintentional neglect, the condition whereby a person is incapable of caring for another. Intentional neglect arises with the deliberate withholding of essential services, medications, or support necessary to maintain a good quality of life. As in child neglect, elderly neglect can result in injury, disease, or death, whether intentional or not. Abuse and neglect often result from familial conflict. Factors contributing to intrafamily elder abuse include postretirement depression, infirmities, dependency, and physical, mental, and emotional illness [28]. Fortunately, a stressful situation does not often result in physical trauma to the aged. Although spouse abuse may begin late in life out of frustration or anger, it more likely involves a long history. The diagnosis of intentional trauma can be more difficult in the aged population. Systemic diseases and medications can lead to increased bruising. Medications, hypotension, visual deficiencies, arrhythmias, and vertigo can lead to falls. Caretakers or persons in authority

The Role of Health Professionals in Diagnosing Patterned Injuries from Birth to Death

29

Figure 2.6 Diffuse neck bitemark and on the arm.

Figure 2.7 Bitemark on the back (left) and on the forearm (right).

might misinterpret the accidental self-induced trauma. All cases of suspected elder abuse should be evaluated by a team of knowledgeable and experienced medical, dental, nursing, social, and law enforcement personnel in a supportive, nonaccusatorial manner. The elderly abused often exhibit denial and shame and might even minimize the sequelae of an assault. Whenever bitemarks are detected, they should be handled similarly to those of child and spousal abuse. Figure 2.6 (right) shows two arm bitemarks on an elderly homicide victim. Note that the proximal mark is quite clear because there was little inflammatory response. Figure 2.7 (left) exhibits a mark on the back of the same victim. Notice how the dependent lividity, resulting in blood pooling within the individual tooth imprints, has caused the marks to become quite clear. Figure 2.7 (right) illustrates a bitemark on the forearm of an 83-year-old Caucasian man. This 4-day-old mark should be compared to the victim’s dentition to eliminate the possibility of a self-inflicted injury.

A bitemark on the upper right chest of a 77-yearold Hispanic man is shown in Figure 2.8 (left). The nursing-home resident, assaulted by his roommate, received at least two bites in addition to other injuries. The bite was inflicted about 3 days prior to this photograph. Figure 2.8 (right) shows the forearm of the same patient, who claimed that the bitemarks were inflicted at the same time. Note the difference in healing.

2.5 Conclusion Whenever there is direct, violent contact between individuals, many forms of trauma can occur, including evidence of biting. Several studies have shown that bitemarks are seen in every form of domestic violence. The first step in bitemark analysis is recognition. The unrecognized bitemark will usually go undocumented and will potentially be lost as a valuable piece of forensic evidence. When bitemarks yield individual dental characteristics, identification of the perpetrator is possible.

30

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 2.8 Bitemark on the upper chest (left) and on the arm (right).

References 1. Jaden. P., and N. Thoennes. 2000. Extent, nature and consequences of intimate partner violence: Findings from the National Violence against Women Survey. Report for grant 93-IJ-CX-0012, funded by the National Instate of Justice and the Centers for Disease Control. Washington, D.C.: NIJ. 2. McKibben, L., E. DeVos, and E. Newberger. 1989. Victimization of mothers of abused children; a controlled study. Pediatrics 84:531–535. 3. Wright, R. J., R. O. Wright, and N. E. Isaac. 1997. Response to battered mothers in the pediatric emergency department; a call for an interdisciplinary approach to family violence. Pediatrics 99:186–192. 4. Felitti, V., R. Anda, D. Nordenberg, D. Williamson, A. M. Spitz, V. Edwards, et al. Relationship of childhood abuse and household dysfunction to many of the leading causes of death in adults. American Journal of Preventive Medicine 14 (4): 245–258. 5. Holtzworth-Monroe, A., L. Bates, N. Smutzler, and E. Sandin. 1997. A brief review of the research on husband violence. Part I: Maritally violent versus nonviolent men. Aggressive and Violent Behavior 2 (1): 65–99. 6. Fenton, S. J., J. E. Bouquot, and J. H. Unkel. 2000. Orofacial consideration for pediatric, adult and elderly victims of abuse. Emergency Medical Clinics of North America 18 (3): 601–617. 7. Lee, L. Y., J. Ilan, and T. Mulvey. 2002. Human biting of children and oral manifestations of abuse: A case report and literature review. Journal of Dentistry for Children 69 (1): 92–95. 8. Sweet, D., and I. A. Pretty. 2000. A look at forensic dentistry. Part 2: Teeth as weapons of violence—Identification of bitemark perpetrators. British Dental Journal 190 (8): 415–428.

9. Pretty, I. A., and D. Sweet. 2001. The scientific basis for human bitemark analyses—A critical review. Science and Justice 41 (2): 85–92. 10. Dhar, V., and S. Tandon. 1998. Bite mark analysis in child abuse. Journal of Indian Society of Pedodontics and Preventive Dentistry 16 (3): 96–102. 11. Mailis, N. P. 1993. Bitemarks in forensic dental practice: The Russian experience. Journal of Forensic OdontoStomatology 11 (1): 31–33. 12. Trube-Becker, E. 1977. Bite-marks on battered children. Journal of Legal Medicine (Germany) 79 (1): 73–78. 13. Simon, P. A. 2000. Recognizing and reporting the orofacial trauma of child abuse/neglect. Texas Dental Journal 117 (10): 21–31. 14. Senn, D. R., J. D. McDowell, and M. E. Alder. 2001. Dentistry’s role in recognition and reporting of domestic violence, abuse and neglect. Dental Clinics of North American Forensic Odontology 45 (2): 343–363. 15. Bowers, C. M., and R. J. Johansen. 2001. Digital analysis of bite marks and human identification. Dental Clinics of North American Forensic Odontology 45 (2): 327–339. 16. Archer, J. 2000. Sex differences in aggression between heterosexual partners: A meta-analytic review. Psychology Bulletin 126:651–680. 17. Carrado, M., M. J. George, E. Loxam, L. Jones, et al. 1996. Aggression in British heterosexual relationships: A descriptive analysis. Aggressive Behavior 22:401–405. 18. Coney, N. S., and W. C. Mackey. 1999. The feminization of domestic violence in America: The woozle effect goes beyond rhetoric. Journal of Men’s Studies 8 (1): 45–58. 19. Fiebert, M. S., and D. M. Gonzalez. 1997. Women who initiate assaults: The reasons offered for such behavior. Psychology Report 80:583–590. 20. George, M. J. 1999. A victimization survey of female perpetrated assaults in the United Kingdom. Aggressive Behavior 25:67–79.

The Role of Health Professionals in Diagnosing Patterned Injuries from Birth to Death 21. Goodyear-Smith, F. A., and T. M. Laidlaw. 1999. Aggressive acts and assaults in intimate relationships: Towards an understanding of the literature. Behavioral Sciences and Law 17:285–304. 22. Lalmuss, D. 1984. The intergenerational transmission of marital aggression. Journal of Marriage and Family 46:11–19. 23. Margolin, G. 1987. The multiple forms of aggressiveness between marital partners: How do we identify them? Journal of Marital and Family Therapy 13:77–84. 24. Milardo, R. M. 1998. Gender asymmetry in common couple violence. Personal Relationships 5:423–438. 25. O’Leary, K. D., J. Barling, I. Arias, A. Rosenbaum, J. Malone, and A. Tyree. 1989. Prevalence and stability of physical aggression between spouses: A longitudinal analysis. Journal of Consulting and Clinical Psychology 57:263–268.

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26. Russell, F. H., and B. Hulson. 1992. Physical and psychological abuse of heterosexual partners. Personality and Individual Differences 13:457–473. 27. Murphy, J. E. 1988. Date abuse and forced intercourse among college students. In Family abuse and its consequences: New direction in research, ed. G. T. Hotaling, D. Finkelhor, J. T. Kirkpatrick, and M. A. Straus, 285–296. Thousand Oaks. CA: Sage Publications. 28. McDowell, J. D. 1994. Domestic violence: Recognizing signs of abuse in patients. Dental Teamwork 23–25. 29. McDowell, J. D., and E. H. Miller. 1996. The dental team’s role in recognizing and reporting domestic violence. Journal of Colorado Dental Association 1:21–37. 30. National Elder Abuse Incidence Study. Final Report Prepared for the Administration on Aging. Washington. DC: U.S. Department of Health and Human Services, 1998.

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Role of the Medical Examiner, Coroner, and Pathologist Joseph H. Davis Contents 3.1 Death Investigative Systems 3.2 A Complete Medical Examiner System 3.3 The Florida Model 3.4 Case Investigative Principles 3.5 Forensic Odontology Service Unavailable 3.6 Forensic Odontology Service Becomes Available 3.7 Bitemarks 3.8 Consultations 3.9 Pattern Variables 3.10 Discord among Experts 3.11 Summary References

33 34 34 35 35 37 37 39 39 40 40 40

3.1â•…Death Investigative Systems

examiners in other parts. Some states have only medical examiners and others a mix of coroners and medical examiners [1]. In some jurisdictions, the coroner may be called a medical examiner even though he or she is not a pathologist. Historical, political, and economic factors seem to determine what system exists. Canada has generally followed the coroner model, although some jurisdictions follow the medical examiner model [1]. A major summation of the death investigative systems of the United States authored by an experienced forensic pathologist and historian was published in late 2009. Dr. Jeffrey M. Jentzen was the chief medical examiner for Milwaukee County, Wisconsin, for many years. His undergraduate education included history. While in Milwaukee he achieved a master’s degree in history and continued history research and study to receive a doctorate of philosophy; he is presently on the faculty of the University of Michigan. Dr. Jentzen’s dissertation was published as Death Investigation in America: Coroners, Medical Examiners, and the Pursuit of Medical Certainty [2]. It is an excellent resource regarding the evolution of death investigative service in the United States. Its 209 pages are a distillation of how the U.S. systems evolved into what exists today. Ten chapters plus an epilogue are supported by a total of 733 notations and an additional selected bibliography. All chapters are worthy; however, certain sections of Chapter 10, “In Search of Reasonable Medical Certainty,” are of functional value to death investigators: Science and the Law, The Burden of Proof, Reasonable

Most death investigators, including consultant forensic odontologists, are familiar with their own jurisdiction but may not be aware of the variables that exist throughout the world, including the United States. In general, systems tend to fall into three broad categories. Most common throughout much of the non-English-Â�speaking world is a system where a magistrate or prosecutor supervises the death investigation. When an autopsy is needed, it may be provided by governmental or university sources. The English-speaking nations tend to follow the coroner system, in which the coroner is appointed as a quasi-judicial agent who supervises death investigations and may conduct inquests of the dead. When the colonies broke away from Britain, the coroner system was brought to the United States, usually as a county elective office. In some states, a justice of the peace office was combined with coroner functions. Medical qualifications were not required. Some elected coroner systems of the United States have been replaced by a system of appointed medical examiners. The first system with a pathologist supervisor and a central laboratory in the United States was in New York City, circa 1915. Maryland replaced its elected lay coroner system with an appointed pathologist medical examiner system in 1939. Other jurisdictions followed in the period following World War II. Today, the United States has a varied mix of systems, including sheriff–coroners in some parts of California and medical 33

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Medical Certainty, Admissibility of Expert Evidence, Evidence-Based Medicine, and Expert Testimony. The most recent summary of death investigative systems of the world was presented at the National Association of Medical Examiners (NAME) Interim Meeting in Seattle, Washington, on February 23, 2010. The program title was “Global Forensic Medicine: LearnÂ� ing from One Another,” Thomas T. Noguchi, chairman, and Jeffrey Jentzen, cochairman. Topics included: Coroner’s Tradition and Current Development in the United Kingdom The Coronial System in Australia Recent Changes Affecting Canadian Practice of Forensic Pathology Recent Developments in Death Investigation in Singapore Legal Medicine in France Italian Legal Medicine The German Development in Legal Medicine and Forensic Pathology Current Japanese Practice in Death Investigation Overview of Forensic Medicine in the People’s Republic of China and Taiwan Forensic Medicine in the Arab and Islamic Middle East Current Practice and New Developments in Death Investigation in Mexico Current Development in Legal Medicine and Forensic Pathology in Peru It was clear that the speakers possessed a common desire to render the best service possible. It was equally clear that traditional governmental systems determine how well forensic pathology and legal medicine are or are not rendered. NAME has published a 64-page summary of the proceedings and issued it to the attendees at the session.

3.2â•…A Complete Medical Examiner System It might be good to define a complete medical examiner system as one where the agency director is an appointed pathologist with authority to carry out scene investigations and to authorize and perform autopsies of public concern. The usual statute defines such deaths as apparent homicide; suicide; accident; suspicious, sudden death when in apparently good health; death unattended by a licensed physician; death of occupational origin; death as public health threat; and so forth. In some states coroners must be physicians, but not in others. A recent trend

is the election of forensically trained nurses as coroners. A universal awareness of the need for training exists. A National Institute of Justice publication, Death Investigation: A Guide for the Scene Investigator, was the first of a series of forensic guidelines and relied upon working groups and reviews by experienced medical examiners and death scene investigators [3]. A number of the guideline projects followed the death investigation model: “Crime Scene Investigation,” “Eye Witness Evidence,” and “Explosion and Bombing” [4]. The death investigator guideline and many other reports (e.g., NAME Forensic Autopsy Standards) are posted free on the Web site of Occupational Research and Assessment (www.orainc.com). Forensic odontology information and pertinent links are found on the American Board of Forensic Odontology (ABFO) Web site (www.abfo.org). Click on “ABFO Manual” for the latest edition [5].

3.3â•…The Florida Model Florida is the second largest land area east of the Mississippi. Its death investigative systems evolved according to local needs. Statehood in 1847 included coroners and peace justices. The constitutional revision of 1885 abolished coroners and provided that the peace justices could hold inquests. As population increased, counties and judicial circuits evolved. The judicial circuits relied upon physicians or pathologists to assist when requested. In 1951, Broward County (Ft. Lauderdale) voted out the peace justices and for the first time the term “medical examiner” was used in Florida. A special act of the legislature, Chapter 27439, Laws of Florida, Special Acts of 1951, set the stage for the county commission to appoint a pathologist in private practice to be designated as the medical examiner. After the death of that pathologist, another was appointed. In time, an associate was appointed to cover the northern part of the county. The office pathology staff grew and served the county well for 19 years. However, the special act included a stipulation that the prosecuting attorney was to be the initiator of an autopsy request. Over time, this stipulation had been overlooked until a lawsuit was filed. As a result of an adverse judgment, the medical examiners resigned and a wellfunctioning entity that served the courts was destroyed through court action [6]. In the meantime, some judicial circuits had created part-time medical examiner systems; others had not. The 1955 legislature enacted a law that established the first full-time central laboratory medical examiner

Role of the Medical Examiner, Coroner, and Pathologist

facility in Florida; this was population based and thus applied only to Dade County [7]. It commenced operation on March 15, 1956. Following the untimely death by stroke of the chief medical examiner, Dr. Stanley Durlacher, I was appointed to head the office 1 year after it began operation and remained until retirement. During my tenure, we certified over 270,000 deaths and performed over 81,000 autopsies, of which I performed 12%. Due to the lack of uniformity of death investigation within the state, the Florida Medical Association sponsored a bill to create a statewide medical examiner system in 1968. I served on the panel of physicians and pathologists who drafted a proposed statute that serves as a model for large area and population jurisdictions. The statute was designed to cope with the rapid demographic, fiscal, and political changes taking place within Florida. In 1970 a statute was enacted that created a statewide medical examiner system [8]. It provided for the state to be composed of separate districts, each serving under a district medical examiner pathologist. The Dade County Medical Examiner Department became District 11. Funding for the system is based upon local needs and fiscal abilities. Categories of deaths requiring medical examiner investigation are listed. A commission provides oversight with Florida Administrative Code rulemaking authority [9]. Included in the rules is the Florida Association of Medical Examiners Practice Guidelines, which includes requirements for dental identification and dental records in cases in which a body cannot be viewed [10]. Homicides constitute about 0.8% of total deaths in Florida. Within that small pool are found those few homicides associated with bitemarks.

3.4â•…Case Investigative Principles Proper case investigative principles do not deviate, regardless of the system. However, system variations may prevent implementation of proper principles. The objective of a death investigation is to derive sufficient data to determine cause and manner of death, to assure civil and criminal justice, and to assure proper certification and disposal of the dead. A system that favors total expeditious investigations by educated, trained, and ethically impartial professionals is preferred. Oversight and review mechanisms ought to exist. In Florida the Medical Examiners’ Commission designates district boundaries, participates in the nomination process for district medical examiners, and has disciplinary and rule-making authority. It has set standards for mandated performance of autopsies in certain

35

types of cases and for record preparation and preservation; it even specifies personal participation of the pathologist during the autopsy procedure [9]. Not all systems in the United States operate with these controls, leaving room for variations based on personal whim; such systems may fail to adhere to proper principles of investigation. A positive influence upon investigative quality is participation in the American Academy of Forensic Sciences and the National Association of Medical Examiners. A death investigation involves different agencies with varied personnel. All must act together in harmony to produce a correlated investigation. The death investigation requires a synthesis of information derived from the scene and witnesses, past medical and social history, and examination of the environment in which the death or injury occurred. Participants in this process are police, crime scene technicians, crime laboratory scientists, medical examiner or coroner investigators, pathologists, toxicologists, and various consultants— forensic odontologists, anthropologists, entomologists, engineers, and so forth. In general, most investigative and decision processes are shared between two agencies: police and coroner or medical examiner. All investigations must be sufficient to develop a database that assures answers for potential future questions pertaining to criminal, civil, scientific, family, and public concern. The key to success is the correlative and cognitive capabilities of the supervisors on all sides.

3.5â•…Forensic Odontology Service Unavailable The genesis of forensic odontology service within a busy medical examiner practice may be exemplified by the following personal experience. It began nearly a halfcentury ago in cramped quarters with a limited budget and no prior local experience to use to forecast needs. The earliest forensic dental identification problem concerned a 35-year-old intoxicated male, blood alcohol 0.22 g percent, who perished from smoke inhalation while smoking in a parked automobile. The body was charred beyond recognition (FigureÂ€ 3.1). Papers in a wallet and witnesses furnished presumptive identity. Police telephoned the chief dental officer of the Bureau of Medicine and Surgery, Department of the Navy, in Washington, D.C. He in turn telephoned the Naval Records Management Center in St. Louis for a record dated July 24, 1946. The information was relayed to the dental officer at the Marine Corps Air Station in Miami, which prepared a chart and compared it with

36

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 3.1â•‡ Body in the first dental identification case

in Miami.

the victim’s teeth. The transmission of record information from the initial inquiry to receipt in Miami was accomplished in only 20 minutes. The initial “bite” case for the medical examiner’s office concerned a brawl in which a man struck a mouth with his fist. Lacerations on his hand became infected. He delayed seeking medical care, gas gangrene set in, and he died. Local knowledge of bitemark analysis was nil in those days. In 1959, a 53-year-old murdered spinster was found strangled in her bedroom. A breast had been amputated and the vaginal area was mutilated after death. Found later at the morgue, beneath dense pubic hair on the skin of the mons pubis, was a curvilinear arc of faint indistinct focal markings that raised a question of a bitemark (FigureÂ€3.2). The overlying pubic hair could have acted as an intermediary to obscure fine detail. At that time the possibility of a bitemark was discussed but not pursued. The assailant confessed to the murder 12.5 years later. A partial palm print and a fingerprint

Figure 3.2â•‡ Miami’s first questionable bitemark case: bitemark on the murdered victim’s mons pubis.

documented his presence at the crime scene. The medical examiner file does not indicate whether his confession mentioned any biting. When skeletal remains were found, the treating dentist confirmed the identity. In one case, a canvas bag containing a skeleton, including skull, was found in a small lake. The initial examination by a dentist noted new gold crowns. The lack of wear facets (FigureÂ€3.3, left) indicated that they had been inserted less than 2 months before death. Eventually, the treating dentist identified the body. The murder victim had been buried in a shallow grave, exhumed by the killers, and dumped in the lake. However, in many skeletal investigations, there are sufficient identity markers apart from the teeth. Dental consultations in those days were limited. The medical examiner would examine the teeth for consistency with known characteristics of the presumed

Figure 3.3â•‡ Lack of wear on gold crowns indicates that death probably occurred within 2 months of dental treatment (left). Meticulous charting of amalgams at age 11 permitted matching to the teeth of a decomposed adult murdered 15 years later (right).

Role of the Medical Examiner, Coroner, and Pathologist

victim. There was no dental profiling nor was there a National Crime Information Center (NCIC) for dental queries for possible matches of the missing to the unknowns. In one presumed identity case, the victim presented with amalgam fillings placed at 11 years of age. The dentist had drawn their outlines on an odontogram (three-Â�dimensional drawing of the dentition) (FigureÂ€ 3.3, right). About 15 years later, the match between ante- and postmortem records was confirmed and the victim identified. Gustafson’s 1966 textbook [11] was at the time most useful in the assessment. Today, one might consider the Manual of Forensic Odontology, a publication of the American Society of Forensic Odontology [12]. An Internet search might provide information on bitemarks, but knowledge of the source, applicability, and veracity of the information must be verified.

3.6â•…Forensic Odontology Service Becomes Available Subsequently, a dentist involved in a skeletal identity of a former patient expressed interest in forensic cases. He volunteered his services, became proficient, and is now an open-ended contractual consultant, an arrangement that encourages visits. Frequency of participation by an unpaid volunteer or a fee-for-service consultant is restricted by the reimbursement system. Medical examiner case investigations frequently involve the mouth. The present consultant is notified for all things of dental interest even if it is an obvious pseudo bite pattern. Whether or not a dental consultant is used depends upon the interest of the consultant and the lack of fiscal restraints on consultations. The more time a dental consultant is encouraged to spend in a medical examiner’s office, the more frequent is the use of dental expertise in problem solving and teaching. The optimum is a relationship that facilitates the use of dental consultations rather than restricts them. As a result of this policy, our dental consultant, Richard R. Souviron, DDS, has examined over 2,300 cases in the Miami-Dade County Medical Examiner Department. Dr. Souviron and his present associate have generated an experience-based instructional publication, a teaching pattern that served me well a half-century ago. I recall when I was about to depart from the U.S. Public Health Service to join the faculty of the Department of Pathology in the School of Medicine at Louisiana State University. I would augment my income by performing autopsies for the coroner of Orleans Parish. In preparation, I studied the 1,349 pages of illustrations in Legal Medicine, Pathology and Toxicology, newly published in

37

1954 by Gonzales et al. [13]. It had scant bibliographic references because it was based upon the combined experience of the authors at the New York City Medical Examiner Office. I prefer to learn from those who have been forced to solve forensic problems instead of those who depend upon publications often copied from previous publications. The culmination of decades of association between forensic odontologists and the Medical Examiner Department of Miami-Dade County is a book by Dr. William E. Silver and Dr. Richard R. Souviron entitled Dental Autopsy [14]. Similarly to the book I studied in 1954, its strength derives from an absence of bibliographic references. It does not copy from publications of others, but rather depends upon extensive practical service at the medical examiner department. A major factor that created the foundation for the book is their enthusiasm and enjoyment, unimpeded by artificial restrictions such as fee for service. They could devote as much time as they wished to build a case to their satisfaction. They could participate in case investigations that were fascinating without restrictions based upon budget concerns. Without doubt, other forensic odontologists share their interests; otherwise they would not become forensic odontologists. How many could visit the death investigative facility unfettered by budget restrictions? I know not. Multiple cases of diverse types and degrees of dental considerations, coupled with their unbounded enthusiasm and lack of restrictive elements, can be found in Silver and Souviron’s book. Its table of contents covers a wide range of topics and includes information about forensic odontology for the neophyte in dentistry and others who render dental opinions in court.

3.7â•…Bitemarks Suspect bitemarks merit special consideration. If the medical examiner or coroner lacks dental resources and no forensic dentist is going to be available to examine the body, the next best thing is to document so that future study may be feasible. The marks should be carefully scrutinized for evidence of abrasions, contusions, petechia in skin, and impressions left by teeth. The bite should be swabbed for DNA, making certain that the swabs and containers are not cross-contaminated. Orientation and close-up photographs must be arranged. A quality camera and film sufficient for future enlargements is needed. Digital photography may suffice if camera resolution permits enlargements without distortion. Color slide film has greater resolution than

38

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

print film. A series of photographs without a scale and a series of photographs with a scale in the same plane as the mark are essential. The ABFO no. 2 scale is preferred. Composition, lighting, color balance (use a color scale in pictures), and focus are critical. A macrolens is useful for the closer views. When satisfactory photographs are completed, a cast or other form of documentation may be made of the bitemark in the event that indentations are present. Local police crime scene personnel or a local dentist may be able to assist. After all documentation to scale is completed, careful total excision of the bitemark— avoiding tissue distortion through shrinkage or other means—is made for two ulterior purposes: to preserve photographically the color and depth of the underlying contusion and for microscopic slide preparations. Eventual histopathological examination is desirable and is outlined in other chapters. Microscopic slides must be identified as to their source. It is well to have the report contain a chart of the bite and the identified sites from which microscopic slides have been prepared. Ideally, a forensic odontologist should participate. The attacker may transfer personal identity substrates to the victim or vice versa; these may include blood, sperm, sweat, or hair. While human bitemarks may be visible, DNA containing saliva is usually not. The crime scene and circumstances might indicate a potential oral transfer regardless of the state of the persons involved. The first step in the investigation is recognition that a set of circumstances might indicate the potential for mouth contact absent of teeth marks. If conscious, the patient might indicate possible sites of mouth contact. If unconscious or dead, exposed portions of skin may indicate a similar potential. These potential areas should be protected and swabbed for DNA as soon as possible. Clothing potentially contaminated with an assailant’s DNA should be carefully preserved and not further contaminated. The attacker’s skin may be found under the victim’s fingernails. One may not assume that first responders thought of this potential. Only in recent years has the value of DNA evidence from saliva been appreciated. Police may focus on bloodstains or obvious injury patterns but may overlook the potential for saliva transfer at other points. Those who follow in the investigative steps must be concerned despite the fact that they were not involved in the initial investigative phase. In fatal events, sooner or later coroner or medical examiner personnel enter the investigation. Systems, response of personnel, and training and experience of personnel are not uniform from one jurisdiction to another. Yet the principles of proper investigation remain the same

throughout all jurisdictions. Accordingly, we should familiarize ourselves with the investigative systems in our jurisdictions and be prepared to respond properly. The coroner or medical examiner investigator may be part of the initial response, although not always. The first rule is that the scene remains undisturbed until crime scene evidence technicians have documented by proper photography the relationship of the body to its surroundings. Any items of potential evidence must be documented. At some point the body is examined. This critical examination may disclose the potential for saliva transfer to any part of the body or its clothing, the potential for patterns of teeth injury, the potential for fingernail scraping evidence, and even latent fingerprints upon skin. Latent fingerprints upon skin, long thought to be impossible, are possible under certain circumstances [15]. An example is a deceased young woman who was found at her place of employment. Her nude body was dusted for fingerprints and a set appeared on a leg above the ankle. Police photographed the prints with a Rolliflex camera equipped with auxiliary clip-on magnifying lenses and used print film. The medical examiner used a Nikon with an expensive macro lens and color slide film. Only the medical examiner’s photographs revealed resolution detail sufficient for classification of the prints. Two lessons were learned: It is wise to build redundancy into the documentation process, and resolution is essential. Camera and film quality must meet specific needs. Police subsequently switched to Nikon cameras with quality lenses. Another lesson learned was that ambient temperature plays a role in the detection of fingerprints on human skin [15]. Similar high-resolution quality photographs must also apply to bitemark evaluation. Clothing may or may not be removed from the body prior to transport. If it is removed, the pathologist and especially the bitemark specialist must know the nature of the clothing and the areas covered by the clothing. A recent example concerned a forensic odontologist who rendered an erroneous bitemark opinion because he failed to require police crime scene photographs. Magnification of the skin may reveal a cloth weave pattern. Also, when clothing is interposed between teeth and skin, saliva DNA should be expected on the clothing, not the underlying skin. Pathologists and their consultants must therefore be certain that all pertinent circumstantial information be furnished before rendering an opinion. If clothing interposition is suspected, the suspicion must be immediately relayed to the police and the forensic laboratory to search the clothing for DNA.

Role of the Medical Examiner, Coroner, and Pathologist

It is incumbent upon all first responders, treatment personnel, police, crime scene investigators, medical examiner or coroner, and pathologist to realize the potential interpersonal victim–assailant linkage within the crime scene and circumstances.

3.8â•…Consultations A pattern injury may clearly be a bitemark, may be a suspicious bitemark, or may clearly not be a bitemark. In any case, a forensic odontologist should be given the opportunity to examine the lesions and judge their relevance. The problem is that not all pathologists or dentists are equally trained, knowledgeable, or experienced. For these reasons, it is prudent to have a qualified set of eyes review the evidence. Two murder victims were found in an adjacent jurisdiction. To the pathologist and the consultant odontologist, some patterns on a body appeared to be human bitemarks. Prudence prevailed and they sought the assistance of a more experienced forensic odontologist, who brought the present author along. Although some patterns might have suggested human teeth marks, an incision into the suspect area clearly demonstrated the superficial nature of surface erosions caused by ants. Prudence on the part of the investigators resulted in a proper final opinion as to the cause of the patterns. Unfortunately, wrongful criminal charges can result when evidence is weak and opinions are strong. Ant bite erosions and irritative dermatitis patterns have been equated with human bite patterns by some odontologists and pathologists with dire consequences. A wise pathologist is familiar with patterns and should judge the validity of consultant opinions. The police and prosecuting attorney are not expected to possess this talent. The forensic pathologist retains accountability and liability for pathology opinions and in some jurisdictions might be liable for consultant opinions.

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3.9â•…Pattern Variables Scene investigators, pathologists, and odontologists recognize that bitemarks can present variable patterns. The inflicted violence is variable. At one end of the spectrum there is licking, mouthing, or sucking without any abrasive or crushing action by teeth. Circumstances must be carefully evaluated before rendering an opinion that potential DNA sites are absent. At the other end of the spectrum is the avulsive bite. An example is the notorious, highly publicized example of boxer Mike Tyson, who bit off part of his opponent’s ear. Sites may be located anywhere on the body. One study suggested that 40% of cases had two or more bites. Males were bitten more commonly on the arms or shoulders; females were bitten on the breast, arms, and legs. This differs from live clinical studies, where hands and fingers were more commonly bitten, reflecting the nature of the problem altercation [16]. Skin thickness varies widely, from the thin skin of the eyelids, nipple, scrotum, and penis to the thick skin of the back, the nose’s overlying cartilage, and calloused palms and feet. Skin varies with age from the thin skin of the infant to the atrophic fragile skin of the elderly. The pattern injury produced by teeth will vary depending on surface contour and interpersonal positions. The observed pattern on a body lying flat on the autopsy table may or may not reflect the pattern of infliction in positional relationship at the precise moment of attack. A bite in the region of the axillary fold will vary with positional change (FigureÂ€3.4). In a situation of the same victim, the same attacker, and more than one bite, the patterns may appear to be from different sources to the untrained eye. Alternatively, a dental impression on the back of the hand or forearm may be caused by the victim’s own mouth resting on that portion of the anatomy after collapse. The pathologist and consultant should anticipate future questions that may arise as the investigation

Figure 3.4â•‡ Posterior axillary fold bitemark without arm extension (left) and with arm raised (right).

40

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

unfolds and wends its way through court. Was the bite inflicted before, during, or after death? Commenting on circumstances of a bite, MacDonald points out a spectrum from amorous to aggressive [17]. One may anticipate a defense claim that a bite was consensual and not associated with the crime. Would a bite leave permanent marks or scarring? In a living victim, permanence of damage may constitute the difference between third-degree battery and second-degree battery and thus affect the criminal charges.

3.10â•…Discord among Experts What happens when experts disagree on bitemark interpretation? Theoretically, equally well-trained experts ought to come to the same conclusions. The first consideration is to determine whether they examined the exact same evidence. For example, original slides and duplicates are not necessarily the same. Original photos that have been digitized are not originals. That being so, the next step is to determine if one of the experts is a pseudoexpert whose motives may be suspect. In an informative and entertaining fashion (including the title “Mountebanks among Forensic Scientists”), Starrs presents 12 case examples with ample references from trial testimony [18]. In reviewing the cases, it is noteworthy that untrustworthy testimony often includes exaggeration of credentials. Aberrant opinion may be difficult to challenge, but falsification of credentials is easy to detect. The greatest problem is when the differing experts are equally well trained, knowledgeable, experienced, and well respected. In theory, discordance of interpretation should be lacking. Nordby, whose background includes medical examiner death scene investigation, has a unique qualification—a doctorate in philosophy with a dissertation on logic. One needs to study his analysis of the factors leading to disagreement between forensic experts, including odontologists [19]. The eyes see, but the viewer observes. Observation is affected by investigative expectation. From observation is derived opinion, which may have been affected by an artifact induced by expectation. The Nordby paper deserves repeated study. Despite great advances in the application of science to forensic problem solving, problems remain. Recently, the National Academy of Sciences issued a report on serious problems within the forensic sciences. A free executive summary report can be downloaded through the Internet [20] with the full version [21].

3.11â•…Summary The medical examiner or coroner is usually the person to notify a consultant forensic odontologist that a suspect bitemark is present. Police or coroner or medical examiner investigators are most likely the first to notice suspect patterns. If they fail, the forensic pathologist is the next step in the detection. At this point the full resources of forensic odontology must prevail. The role of the forensic odontologist as part of the death investigative team is today an accepted fact. A complex bitemark case may occur in any police or coroner or medical examiner jurisdiction, large or small, rural or urban. Lack of local resources is no excuse for an inadequate investigation. Local egos must never override a need to seek consultation. Police, forensic pathology, and forensic odontology networks exist. Initial “what to do” consultation is only a telephone call away. If an arrest is made and a criminal trial ensues, courts will not tolerate a lack-of-resources excuse for an inadequate investigation. Coroner or medical examiners and their forensic pathologists must plan for this eventuality if their community and justice will be served. Ideal planning should encompass the total death investigation system, including infrastructure and training, professional standards and quality, the criminal and civil justice systems, public health needs, disasters, and homeland security.

References 1. Combs, D. L., R. G. Parrish, and R. Ing. 1995. Death investigation in the United States and Canada. Atlanta: Centers for Disease Control and Prevention. 2. Jentzen J. M. 2009. Death investigation in America, coroners, medical examiners, and the pursuit of medical certainty. Cambridge, MA: Harvard Univ. Press. 3. NIJ death investigation: A guide for the scene investigator. http://www.ncjrs.gov/pdffiles/167568.pdf 4. Other NIJ guidelines of interest to forensic odontologists: Crime scene investigation (http://www.ncjrs.gov/ pdffiles1/nij/178240.pdf); Eye witness evidence (http:// www.ncjrs.gov/pdffiles1/nij/1782X0.pdf); Explosion and bombing (http://www.ncjrs.gov/pdffiles1/nij/181819.pdf); www.abfo.org (click on “ABFO Manual” for download). 5. Rupp, J. C. 1971. Death of a medical examiner system. Journal for Sciences 16:420–437. 6. Chapter 30228, Laws of Florida, 1955. 7. Chapter 406, Florida Statutes. 8. Rules 11G 1–5, Florida Administrative Code. 9. http://www.fdle.state.fl.us/Content/CJST/Documents/ Medical-Examiners-Commission-(MEC).aspx

Role of the Medical Examiner, Coroner, and Pathologist 10. Scroll down to and click on MEC 2008 Annual Workload Report. 11. Gustafson, G. 1966. Forensic odontology. London: Stapler Press. 12. Bowers, C. M., and G. Bell, eds. 1995. Manual of forensic odontology, 3rd ed. Lubbock, TX: American Society of Forensic Odontology (online at www.newabfo.com). 13. Gonzalez, T. A., M. Vance, M. Helpern, and C. J. Umberger. 1954. Legal medicine, pathology and toxicology, 2nd ed. New York: Appleton–Century–Crofts. 14. Silver, W. E., and R. R. Souviron. 2009. Dental autopsy. Boca Raton, FL: Taylor & Francis. 15. Sampson, W. C. 1996. Latent fingerprint evidence on human skin (part 1). Journal of Forensic Identification 46:188–195.

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16. Vale, G. L., and T. T. Noguchi. 1983. Anatomical distribution of human bitemarks in a series of 67 cases. Journal of Forensic Sciences 28:61–69. 17. MacDonald, D. G. 1974. Bitemark recognition and interpretation. Journal of Forensic Sciences 14:229–233. 18. Starrs, J. E. 1988. Montebanks among forensic scientists. In Forensic science handbook, vol. 2, ed. R. Saferstein. Englewood Cliffs, NJ: Prentice Hall. 19. Nordby, J. J. 1992. Can we believe what we see, if we see what we believe? Expert disagreement. Journal for Sciences 37:1115–1124. 20. http://www.nap.edu/nap-cgi/report.cgi?record_id=12589â•‰ &type=pdfxsum 21. http://www.nap.edu/openbook.php?record_id=12589â•‰ &page=1

4

The Team Approach in Bitemark Investigation Veronique F. Delattre Contents 4.1 Introduction 4.2 Advantages of the Team Approach during Bitemark Investigation 4.3 Potential Team Members and Their Roles 4.3.1 Forensic Odontologist 4.3.2 First Responders 4.3.3 Law Enforcement Officials and Crime Scene Investigators 4.3.4 Sexual Assault Nurse Examiner 4.3.5 Medical Examiner 4.3.6 Coroner 4.3.7 Forensic Pathologist 4.3.8 Forensic Photographer 4.3.9 Criminalist 4.4 Bitemark Evidence Detection, Description, and Collection 4.4.1 Initial Forensic Dental Evaluation 4.4.2 Trace Evidence Detection and Collection 4.4.3 Forensic Dental Evidence Collection 4.5 Developing a Teamwork Protocol for Bitemark Investigation 4.5.1 Initial Phase 4.5.2 Protocol Development Phase 4.5.3 Testing Phase 4.5.4 Updates and Revisions 4.6 Sample Team Protocol for Collecting Patterned Injury Evidence 4.6.1 At the Crime Scene 4.6.2 At the Morgue 4.7 Teamwork in Smaller Jurisdictions 4.8 Conclusion References

4.1â•…Introduction

43 44 44 44 44 44 45 45 45 45 45 45 45 45 47 47 47 47 47 48 48 48 48 48 48 48 48

way in designing the team’s protocol. Forensic odontologists, also called forensic dentists, tend to work within a framework of accepted standard operating procedures (SOPs). The majority of odontologists, whether they are certified diplomates of the American Board of Forensic Odontology (ABFO) or not, routinely follow the principles set forth by the ABFO guidelines [3]. Despite recent technological advances in bitemark analysis, the most important asset is still a thorough and well-planned collaborative investigation. Whether or not the investigation takes place in a jurisdiction with unlimited resources, high-tech equipment, and modern laboratory facilities, any bitemark investigation will benefit from the interaction of well-trained personnel working as a multidisciplinary team.

Integrating the philosophy of multidisciplinary teamwork during bitemark investigation will increase success in the recognition, collection, chain of possession, storing, analysis, and effective court presentation of bitemark evidence. Investigators are increasingly challenged to deliver scientific evidence of the highest evidentiary value in bitemark investigations. Jury members and the public have developed high expectations concerning scientific forensic evidence as a result of being exposed to forensic science in the popular media [1]. Bitemark evidence is considered a strong factor in the investigation of many crimes [2], and the forensic dental consultant is the logical professional to lead the 43

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Preplanning a multidisciplinary team approach to bitemark investigations will ensure that (1) no evidence is overlooked, (2) no evidence is altered or destroyed before collection, and (3) each of the forensic specialists involved in the investigation participates in the most appropriate sequence for optimal evidence collection.

4.2 Advantages of the Team Approach during Bitemark Investigation The team approach is especially appropriate for conducting tasks that are high in complexity and have many interdependent subtasks. A team is defined as a group of people linked by a common purpose, such as during a bitemark investigation. Teamwork will reduce feelings of isolation among the various forensic scientists working on the same case and will keep the “big picture” at the center of the investigation. Teamwork among forensic scientists also ensures that one forensic specialty’s method of evidence collection will not damage the particular evidence needed by another specialty or undermine the efforts of others on the same case. Even the most modern, high-tech methods of evidence analysis may be of no evidentiary value if the primary evidence is overlooked, altered, damaged, or destroyed before each expert is able to adequately collect his or her portion of the bitemark evidence to complete his or her portion of the investigation. The team approach allows each member to understand specific duties ahead of time, delineates his or her area of evidence collection, and reinforces the responsibilities in the overall investigation scenario. These expectations should be clearly spelled out in a written protocol to minimize confusion, duplication, and errors. This multidisciplinary approach will enhance the perceived cohesiveness and validity of the various forms of evidence presented to the jury [4].

4.3 Potential Team Members and Their Roles There are two obvious categories of bitemark recipients: the living and the deceased. While the overall evidence needed for bitemark analysis will generally be the same in both the living and deceased, the team protocol and specific team members will vary depending upon the specific circumstances in the case. Presented in this section is a brief review of potential bitemark investigation team members and their roles.

4.3.1 Forensic Odontologist The forensic odontologist is central to any bitemark investigation. A forensic odontologist is a dentist who specializes in the proper handling, examination, and evaluation of dental evidence, which may then be presented in the interest of justice. An odontologist’s duties on the bitemark investigation team include the recognition, recording, collection, preservation, analysis, and comparison of pattern injuries—or, more specifically, bitemarks. As a result of the recommendations of the 2009 National Academy of Sciences report, Strengthening Forensic Science in the United States: A Path Forward [5], medical examiner and coroner offices are increasingly choosing to work with certified forensic odontologists rather than with those who are not certified. Among other recommendations, the report advises that all forensic science disciplines must have a strong scientific foundation, that all forensic scientists should be cer tified, and that all forensic scientists should hold themselves to a code of ethics. In the field of forensic odontology, certification is granted by the American Board of Forensic Odontology based upon the candidate’s personal and professional record of education, training, experience, and achievement, as well as the results of a formal examination. The ABFO is recognized by the American Academy of Forensic Sciences and accredited by the Forensic Specialties Accreditation Board [6]. A directory of certified diplomates of the American Board of Forensic Odontology can be found on the ABFO’s Web site [7]. 4.3.2 First Responders First responders (paramedics, emergency medical technicians, forensic nurses, and emergency room physicians) may be the first to recognize a suspected bitemark. Their role is to alert law enforcement officials or protective services. They may also begin the forensic evidence collection process, in accordance with their training and institutional protocol. 4.3.3 Law Enforcement Officials and Crime Scene Investigators Law enforcement officials and crime scene investigators are responsible for securing, evaluating, and photographing the scene. They also assemble physical evidence for future scientific evaluation. Their expertise in recognizing and properly collecting physical evidence is essential to solving as well as prosecuting crimes. Law enforcement officials and crime scene investigators produce detailed reports on the crime scene, including their own

The Team Approach in Bitemark Investigation

observations and interviews with witnesses, suspects, and victims. 4.3.4 Sexual Assault Nurse Examiner The sexual assault nurse examiner (SANE) is a registered nurse who has completed both didactic education and clinical training in caring for patients who have been sexually assaulted. The basic training includes methods of evidence collection for the adult or adolescent population, leading to the SANE-A (adult/adolescent) designation. With more experience and continued education, the SANE-A is educated regarding the interpretation of findings specifically associated with child sexual abuse, leading to the SANE-P (pediatric/adolescent) designation [8]. Certification is achieved through the International Association of Forensic Nurses’ Forensic Nursing Certification Board (FNCB) [9]. 4.3.5 Medical Examiner The medical examiner is a physician who investigates the facts when a person has died a sudden, unexpected, or violent death. He or she is elected or appointed to serve a specific jurisdiction and is tasked with determining the identity of an unknown person and the cause and manner of the death that is under investigation [10]. The manner of death will be declared one of the following: natural, homicide, suicide, accidental, or undetermined. The cause of death is the disease or injury that initiated the lethal chain of events. While a number of complications and contributing factors may have been involved, the cause of death is the initial underlying reason that led to the individual’s death. 4.3.6 Coroner The coroner is a public official charged with inquiry into deaths that fall into certain categories. The coroner is not required to be a physician or be trained in medicine. Depending upon the jurisdiction defining the responsibilities, the coroner may not necessarily be a physician and may contact physicians or forensic pathologists to perform autopsies when there appears to be a suspicious manner of death that requires a forensic autopsy [11].

45

trained to perform forensic autopsies, to evaluate patient medical history and law enforcement reports that may help determine the manner and cause of death, to collect biological trace evidence and secretions, to document evidence of sexual assault, and to reconstruct how a person received injuries, including direction, type, and manner thereof [12]. 4.3.8 Forensic Photographer A forensic photographer visually records the crime scene and the body for documentation, further study, and use in court presentation. The duties of a forensic photographer are determined by the hiring agency. Some duties may include photographing crime scenes, autopsies, and articles of evidence, and digitizing hard copy photographs or radiographs. A forensic photographer should be well trained in alternate lighting techniques; macrophotography; specialized lighting such as ultraviolet (UV), infrared (IR), and alternate light imaging (ALI) techniques; and the use of filters [13]. 4.3.9 Criminalist Many agencies employ criminalists, who have at least a bachelor’s degree in chemistry, biology, physics, molecular biology, or a related science. They are charged with analyzing, comparing, identifying, and interpreting physical evidence. A criminalist’s duties may vary within different agencies, depending upon the needs of the jurisdiction. Criminalists can be relied upon to work well with a wide variety of evidence, such as hair, fiber, blood, body fluids, soil, ballistics, and tool marks. With their expertise in trace evidence analysis, they are often the backbone of a bitemark investigation. The criminalist may also be the scientist tasked with DNA investigation by extracting, amplifying, and comparing DNA samples to determine if there is a correlation between a suspect and a bitemark. The certifying organization for criminalists is the American Board of Criminalistics [14].

4.4 Bitemark Evidence Detection, Description, and Collection 4.4.1 Initial Forensic Dental Evaluation

4.3.7 Forensic Pathologist In the course of bitemark investigation, the forensic pathologist can be especially valuable in evaluating the tissue involved in any suspicious pattern injury, with the main goal of determining the timing and extent of the injury. Forensic pathologists are specifically

When possible, the forensic odontologist should first view the pattern injuries that are under investigation with the medical examiner in charge of the case. The purposes of the initial collaborative session are to determine a consistent numbering system to distinguish each injury to be evaluated, agree upon the terminology to

46

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Case Number 123 The victim’s maxillary intercuspid distance measures: approximately 32 mm The victim’s mandibular intercuspid distance measures: approximately 27 mm

Injury #

Anatomical Location

Approximate Size At Widest Points (mm)

Description

Consistent With A Human Bitemark?

Evidentiary Value

1

Back

30 × 31

Discoloration

Yes

Moderate

2

Flexor right forearm

26 × 28

Discoloration

Yes

Low

3

Medial right forearm

28 × 30

Discoloration and areas of mild abrasion

Yes

Moderate with some details visible

4

Extensor right forearm

26 × 29

Discoloration

Yes

Moderate with some details visible

5

Extensor left wrist

25 × 25

Dark discoloration

Yes

High

6

Extensor left forearm

25 × 27

Indistinct area of discoloration

Yes

Low

7

Extensor medial left forearm

25 × 27

Discoloration

Yes

Low

8

Medial left wrist

26 × 30

Diffuse discoloration

Yes

Low

9

Flexor left forearm

30 × 30

Discoloration

Yes

Moderate

10

Left bicep

29 × 32

Discoloration

Yes

Moderate with some details visible

11

Posterior left thigh

30 × 30

Discoloration

Yes

Moderate with some details visible

Figure 4.1 This table summarizes the mutually agreed-upon terminology that was used during an investigation on a victim with 11 suspected bitemarks. Use of consistent terminology among team members will maximize the effectiveness of future testimony regarding the injuries.

describe the anatomical location of each injury, and agree upon the terminology to describe each injury. Using a table and diagrams or orientation-type photographs will facilitate the communication process among members. Figure 4.1 depicts a table that summarizes the agreed-upon terminology of multiple injuries seen during a bitemark investigation. Other team members should strive to use the same numbering and terminology system to present their

particular evidence. Of course, the individual team members’ official reports will use appropriate terms as stated in their specialties’ guidelines. A consistent numbering system and terminology by all experts will serve to maximize the effectiveness of any future testimony regarding the injuries, particularly in cases where there are multiple injuries. Figure 4.2 depicts orientation-type photographs of two of the injuries described in the summary table.

Figure 4.2 Orientation-type photograph, with information about the injury number and anatomical location of the second and the ninth bitemark described previously in the summary table.

The Team Approach in Bitemark Investigation

47

Figure 4.3 Diagram of the arms and hands, which can be helpful in documenting areas of injury and facilitate communication between team members.

4.4.2 Trace Evidence Detection and Collection Trace evidence detection and collection begins with the covered or bagged body parts. Evidence detection proceeds using white light, ultraviolet, and alternate light sources and, at times, infrared light. Obvious injuries and fluorescent areas are marked on diagram sheets, such as those seen in Figure 4.3. Similar diagram sheets can be found on the Web site of the Armed Forces Institute of Pathology [15]. Fluorescing items, such as dried bodily fluids, are photographed in vivo, catalogued, collected using sterile saline, and appropriately stored for DNA analysis. To avoid contamination with one’s own saliva, one should not moisten an evidence-envelope seal by licking. Collected items and trace evidence swabs are labeled with case number, date, and collector initials and are placed in appropriate sealed and labeled containers. 4.4.3 Forensic Dental Evidence Collection Only a summary of steps will be presented in this section. The guidelines to follow in any bitemark investigation can be found in other chapters of this book and in the American Board of Forensic Odontology Diplomates’ Reference Manual [16]. • Determine whether each injury in question is a potential bitemark [17]. • Swab each injury if you cannot verify that it has previously been processed. • Photograph and document the potential bitemark injury.

• Take impressions of the potential bitemark, if indicated. • Consider whether total excision, preservation, or fixation of the injured skin is indicated.

4.5 Developing a Teamwork Protocol for Bitemark Investigation 4.5.1 Initial Phase During the initial phase, when a teamwork protocol in bitemark investigation of the deceased is being developed, it is important for each forensic specialist to provide an overview of his or her evidence needs and guidelines to the team members. Some critical questions should be answered during this phase. Who will collect DNA samples? How and when? How will the body be protected from further contamination during transportation to the morgue? Who records the chain of possession? How is it registered? Who is responsible for the transfer of evidence? To which specialist should the exhibit or specimen go? 4.5.2 Protocol Development Phase During a scheduled conference of all team members, the specialty-specific guidelines should be reviewed for redundancy or steps that might damage another member’s evidence. For example, in vivo photographs may be taken first; then, the trace evidence can be collected and the injury washed to allow further photographs to be taken as appropriate.

48

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

4.5.3 Testing Phase As many potential members of the team as possible should attend a simulated case scenario as part of a training process to assure that each member clearly understands his or her duties, limits, and responsibilities. It should quickly become apparent that a particular team member will be skilled at orchestrating parts of the investigation and that a certain flow of duties will result. During this phase, the team will need to identify specific roles, the order in which each member will function, and the evidence to be collected by each member. 4.5.4 Updates and Revisions Once the team protocol has been developed, tested, and undergone real-life implementation, it is important to review the protocol and make any necessary updates or revisions as needed.

4.6 Sample Team Protocol for Collecting Patterned Injury Evidence 4.6.1 At the Crime Scene • • • •

Document the suspected bitemark injuries. Photograph the suspected bitemark injuries. Collect DNA samples at the scene. Cover any body part suspected to have trace evidence material: bag the hands and feet, cover breasts, etc. • Place deceased in a new or thoroughly decontaminated, sealed body bag. • Transport body to the morgue. 4.6.2 At the Morgue • Issue a case number. • Follow routine check-in procedures of the decedent. • Take sequential photographs throughout the check-in procedures. • In some jurisdictions, full-body radiographs are taken through the body bag before unsealing it. • Remove the body bag’s seal and open the body bag in the presence of the appropriate persons. • Take full-body radiographs. • Begin the evidence collection and autopsy protocol.

4.7 Teamwork in Smaller Jurisdictions In smaller jurisdictions, it may take only a few forensically trained individuals to serve as the bitemark investigation team. Regardless of specialty, each team member must become familiar with and trained in the skills involved in recognition, proper collection, and storage of all types of bitemark evidence for the purpose of evaluation by outside consultants or for effective court presentation.

4.8 Conclusion Many factors can affect the development and use of the team concept in bitemark investigation, including numbers and types of forensic scientists in a jurisdiction, jurisdictional rivalries, and financial resources. There can be as many organizational models as there are cities, counties, states, and countries. Teamwork in bitemark investigation requires that each forensic scientist perform a specific task efficiently in order to produce the requisite unbiased scientific result. Committing to the philosophy of a multidisciplinary teamwork approach during bitemark investigation will increase the potential for consistently high-quality evidence recognition and collection and will facilitate the cohesiveness of various forensic specialties in a court presentation of bitemark evidence. Preplanning a multidisciplinary team approach to bitemark investigations will help make certain that no pertinent piece of evidence is overlooked, altered, or destroyed before collection and that each of the team members participates in the most appropriate sequence for optimal evidence collection. When it comes to bitemark investigation, the acronym “TEAM” serves to remind the individual forensic specialists that “together everyone achieves more.”

References 1. Shelton, D. E., Y. S. Kim, and G. Barak. 2006. A study of juror expectations and demands concerning scientific evidence: Does the “CSI effect” exist? Vanderbilt Journal of Entertainment and Technology Law 9 (2): 331–368. 2. Vale, G. L. 1996. Dentistry. Bite marks and the investigation of crime. Journal of California Dental Association 24 (5): 29–34. 3. McNamee, A. H., and D. J. Sweet. 2003. Adherence of forensic odontologists to the ABFO guidelines for victim evidence collection. Forensic Science 48 (2): 382–385.

The Team Approach in Bitemark Investigation 4. Delattre, V. F., R. Reynolds, A. Santos, and P. G. Stimson. 2002. Teamwork in action—Integration of the forensic sciences during bitemark investigations. Proceedings of the American Academy of Forensic Sciences Annual Meeting, Atlanta, 2002. 5. National Academy of Sciences. 2009. Strengthening forensic science in the United States: A path forward. Committee on Identifying the Needs of the Forensic Sciences Community: Committee on Applied and Theoretical Statistics, National Research Council. Washington, D.C.: National Academies Press. 6. American Board of Forensic Odontology diplomates reference manual. October 2009. Colorado Springs, Section I, p. 9. 7. American Board of Forensic Odontology. October 2009. Member list. http://www.abfo.org/member_list.htm 8. Forensic Nursing Certification Board. 2009. Certification board and history. http://www.iafn.org/displaycommon. cfm?an=1&subarticlenbr=8 9. International Association of Forensic Nurses. MemberÂ� shipâ•¯handbook.â•¯http://www.iafn.org/associations/8556/ files/Membership Handbook.pdf

49 10. National Association of Medical Examiners. 2007. So you want to be a medical detective. http://thename.org/ index.php?option=com_docman&task=doc_details&gi d=14&Itemid=26load&gid=14&Itemid=26 11. National Association of Medical Examiners. 2006. What is a coroner? http://thename.org/index.php?option=com_Â� content&task=view&id=36&Itemid=42 12. National Association of Medical Examiners. 2006. What is a forensic pathologist? http://thename.org/index.phpâ•‰ ?option=com_content&task=view&id=38&Itemid=42 13. International Association for Identification. Frequently asked questions for forensic photographers. http://www. theiai.org/certifications/imaging/faq.php 14. American Board of Criminalistics. http://www.criminalistics.com/cert_ovw.cfm 15. Armed Forces Institute of Pathology. Autopsy diagrams. http://www.afip.org/consultation/AFMES/forms/ 16. American Board of Forensic Odontology Diplomates’ Reference Manual. October 2009. Colorado Springs, Section III. 17. Delattre, V. F., and P. G. Stimson. 1998. Bite marks vs. other injuries—Forensic odontological evaluation of a homicide. Proceedings of American Academy of Forensic Scientists 5:133.

Description of the Bitemark

III

5

The Nature of Bitemarks Mark L. Bernstein Contents 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8

Definition Spelling Evidentiary Value Demographics Pathology of the Cutaneous Bitemark Anatomy of the Typical Cutaneous Human Bitemark Class Characteristics of the Human Cutaneous Bitemark Variations of Bitemark Patterns 5.8.1 Central Contusion 5.8.2 Linear Abrasions and Contusions 5.8.3 Lingual Markings 5.8.4 Tongue Thrusting 5.8.5 Acute Inflammatory Reaction 5.8.6 Uninterrupted Arches 5.8.7 Tooth Indentations 5.8.8 Double Bite 5.8.9 Multiple and Superimposed Bites 5.8.10 Weave Patterns 5.8.11 Excessive Ecchymosis and Abrasion 5.8.12 Partial Bitemarks 5.8.13 Indistinct or Faded Bitemarks 5.8.14 Avulsive Bites 5.8.15 Healed Bitemarks 5.8.16 Postmortem Bitemarks 5.9 Individual Characteristics of the Human Bitemark 5.10 Dog Bites 5.11 Bitemarks in Other Substrates References

5.1â•…Definition

53 53 54 54 55 55 55 57 57 57 58 58 58 58 58 59 59 60 60 60 61 61 61 62 62 62 64 64

action of jaws during intended biting if a recognizable pattern is not produced. These other tooth-to-skin interactions are still important even if not distinguished by the term “bitemark” because they can be responsible for infection, tissue destruction, or transmissible diseases, and they can transfer DNA in saliva. However, by convention, the term “bitemark” signifies to the forensic odontologist an injury that, by its pattern, helps establish its origin from teeth.

A bitemark can be generally defined as a pattern made by teeth in a substrate. Since the teeth can be of human or animal origin and the substrate can be skin, food, or a firm but compressible substance, more specific definitions are needed. Most bitemarks of forensic interest involve the contact between human teeth and skin. The American Board of Forensic Odontology defines the human cutaneous bitemark as follows: “An injury in skin caused by contacting teeth (with or without the lips or tongue) which shows the representational pattern of the oral structures” [1]. The definition excludes other nonpatterned injuries made by teeth contacting skin such as might be encountered by a fist to the mouth. It also excludes the closing

5.2â•…Spelling Three terms—bitemark (one word) [2], bite mark (two words) [3–8], and bite-mark (hyphenated) [9–12]—â•‰ appear in the literature. “Bite mark” is most widely used. 53

54

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

This form implies a type of mark, whereas “bitemark” connotes an entity unto itself and that is recognizable as such. It is considered to be a more progressive term, signifying that odontologists have accumulated a sufficient body of knowledge to dignify the form. “Bite-mark” should be reserved for use as a compound adjective as in “bite-mark analysis” [1]. The point may be moot since all forms are acceptable, yet it is important to consider all terms when performing a computer literature search. (Editor’s note: For the purposes of this edition, the term “bitemark” has been adopted, excepting cited quotations and references where it is spelled differently.)

5.3â•…Evidentiary Value The presence and recognition of a bitemark in a living or deceased individual or in a substrate at a crime scene is relevant in both civil and criminal cases. The mere presence of an identifiable bitemark in a purported crime is significant even if the pattern fails to implicate a specific biter. In a case of disputed child abuse, where the injuries are arguably accidental, the presence of a bitemark supports an accusation of abuse. In alleged sexual assault, when DNA evidence is apt to confirm the identity of the accused, the defense of consensual sex is less believable if bitemarks are found. Even a poor-quality bitemark, if recognized, can prompt trace evidence collection for salivary DNA and amylase. Many bitemarks do record the distinctive morphologic features of the biter’s dentition, offering an opportunity to identify the biter based on metric and pattern analysis. The discovery of bitemarks, like fingerprints, offers hope of perpetrator identification, but there are important differences between the two. When latent fingerprints are discovered at a crime scene, this means only that a certain person touched something at an unspecified time. There is not necessarily a link to the crime. In contrast, the presence of a bitemark in skin indicates a violent interaction between individuals as well as a rough temporal connection to the event.

psychological disturbance, organic brain disease [13], severe pain [14], epileptic seizures, an attempt to frame another individual, or forcible insertion of an arm into the victim’s mouth during a fight to subdue the victim or prevent crying out [10,15]. An unusual one-arched bitemark was reported in a woman who fell on her denture [16]. Other sources of human bitemarks include partly eaten food or chewing gum discarded during robberies, or teeth contacting inanimate objects during fights. Animal bites, particularly from dogs but also from other mammals, reptiles, and fish, are of forensic interest, including postmortem predation from field animals and insects. Bitemarks may appear on any skin surface [7,9,17], although they are found with greatest frequency on the breasts, arms, legs, and head. Females are bitten four times as often as males. In heterosexual assaults on women, breasts, arms and legs, face and neck, pubic area, and buttocks are frequent sites; in male homosexual attacks, the upper back, shoulders, axillae, penis, and scrotum are favored. Abused children are randomly bitten with frequent bites on the face and back [6,7]. Rawson et al. reported that 43% of bites on children occurred in the head and neck [18]. In Pretty and Sweet’s study, all male children had genital bites [19]. Meta-analysis of these multiple studies is not entirely accurate because they derived cases from different sources: hospital-based populations [18,20], coroner’s cases [9], and court cases [19]. Multiple bites are found in 40–48% of bitemark cases [19,20]. Pretty and Sweet caution that, when one bite is detected, others should be sought [19]. In dog maulings where multiple bites are sustained, the extremities are bitten and deep, perforating bites of the neck and avulsive bites of the scalp are common (FigureÂ€5.1).

5.4â•…Demographics Bitemarks are seen in crimes of passion—homicide, rape or sexual assault, domestic violence (child, partner, elder abuse), and battery. The bitemark recipient may be the victim of a crime or the perpetrator of a crime—either as an aggressor or in self-defense. Rarely, self-biting has been reported in association with mental retardation,

Figure 5.1â•‡ Fatal neck perforation and avulsion of scalp in a dog mauling.

The Nature of Bitemarks

5.5 Pathology of the Cutaneous Bitemark Fingerprints, impressions, and patterned injuries all represent a transfer of a pattern from one medium to another. This is where the similarity ends. The visibility of a fingerprint derives from deposits of sweat and dirt on the crests of the friction ridges that are passively transferred to a smooth surface. The deposit faithfully reproduces the anatomy of the ridge detail in much the manner of a rubber stamp imprint. An impression is a three-dimensional indentation occurring when a hard material displaces a softer material. It retains the depression after the two materials are separated. A patterned injury such as a bitemark is made visible not by a transfer of material and not often by indentations, but rather by a vital response of the bitten tissue. It may include the superficial scraping of epithelium by the contacting teeth (abrasion), the bleeding within skin by the pressure of the teeth (contusion), or the tearing of skin by teeth (laceration) that renders the bitemark visible. Bleeding or scraping of skin under assault is not obliged to conform precisely to the anatomy of the object that produced it. The bleeding can extend beyond the tooth marks. Conversely, bitten skin may not have been sufficiently damaged to react at all. The bitemark is not an imprint or impression, but rather a reactive response generated by injured skin that is invariably less precise than a direct recording. A myriad of other unpredictable and nonreproducible variables further confound the patterns displayed in a bitemark. These include skin thickness, elasticity, curvature, texture, vascularity, pigmentation, underlying support, and position during biting. Also important are the age and gender of the victim and the presence of systemic diseases and medications. The dynamics of biting—force and direction—affect the resulting pattern, as do surface characteristics of contacting teeth. In spite of all these variables, it remains a maxim of forensic pathology that abrasions and contusions often reproduce the pattern of the offending agent. It is this observation that affords odontologists the opportunity to determine whether or not a specific dentition might have produced a given bitemark.

5.6 Anatomy of the Typical Cutaneous Human Bitemark The human dental formula is I2/2, C1/1, P2/2, M3/3— indicating two incisors, one cuspid, two premolars, and three molars in each upper and lower quadrant. The 16

55

maxillary and 16 mandibular teeth are arranged along parabolic arches. Typically, it is only the six anterior teeth in each arch (incisors and cuspids) that participate in a bitemark. Occasionally, first premolars and, rarely, molars mark. During biting, the jaws approximate one another, the biting (incisal) surfaces of the teeth contact skin with various degrees of force, and the skin reacts, registering a pattern that resembles a mirror image of the incisal signature. Our genetics determine the general characteristics that define the size, shape, and arrangement of our dentition. All humans are expected to share these basic dental characteristics, which are similarly reproduced in well-inflicted bitemarks. This enables the forensic investigator to examine a patterned injury and, by virtue of these characteristics, identify it as a human bitemark. “Class characteristics” is a term borrowed from tool mark analysis [6]. It refers to morphologic features in a transfer pattern that are expected to be reproduced by any and all members of a certain class or set and serve to identify the set from which it was derived. Thus, a certain pattern in a footprint or tread mark would enable the identification of the brand of sole or tire. For our purposes, class characteristics of the human dentition are features that, when seen in a patterned injury, allow its identification as a generic human bitemark.

5.7 Class Characteristics of the Human Cutaneous Bitemark The classic human bitemark in skin appears as a circular or oval, ring-shaped or doughnut-shaped injury composed of two opposing U-shaped arches facing one another and separated from each other at their bases. Each arch features an alignment of individual contusions, abrasions, and/or lacerations that approximate the size, shape, and arrangement of human teeth. The incisors, located toward the center of each arch, record as a row of four linear or rectangular marks per arch. The cuspids (or canines) produce circular, triangular, or diamond-shaped marks toward the edges of the arches, with their size determined by their incisal surface area and depth of penetration of their conical cusps. If a premolar marks, it produces a cuspid like marking aligned with the arch and possibly a second mark a few milli meters within the arch, representing the lingual cusp. Since the upper and lower arches have distinguishing features, class characteristics can be defined for the maxillary and mandibular dentitions. Upper central incisors are broad and can be expected to leave linear

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

markings measÂ�urÂ�ing 8–9 mm. The narrower lateral incisors leave similar marks of 6–7 mm. Since lateral incisors do not typically reach the occlusal plane, these shorter teeth do not place as much pressure on skin and may leave less intense marks or no marks at all. The longer, pointed cuspids often leave well-defined marks. Their position at the corners of the arch marks the area where the arch curves most sharply. In the lower arch, the incisal widths of the central and lateral incisors are less disparate, measÂ�urÂ�ing ∼5.5 and 6.0 mm, respectively. If lower premolars mark, only the buccal cusps are likely to record since the lingual cusps are diminutive. The measÂ�ureÂ�ments are based on the study of Moorrees et al. [21], which should be consulted for more precise values, standard deviations, and ranges. The upper arch is larger than the lower, and its intercuspid distance averages from 32.3 mm [22] to 33.6 mm [23] ± 2.5 mm for 1 standard deviation (SD). The range, based on nearly 400 cases, was 21.3–41.0 mm [22]. The mandibular intercuspid distance averages 25 mm [22,23] ± 1.85 mm for 1 SD and ranged from 11.6 to 33.0 mm [22]. Barsley and Lancaster obtained slightly higher mean intercuspid distances of 35.9 ± 3.3 mm (maxillary) and 28.1 ± 2.9 mm (mandibular) because they measÂ�ured from the disto-occlusal aspects of worn canines rather than the cuspal midpoints [24]. They also found that 98.7% of all mandibular arches measÂ�ured <35 mm and 78% measÂ�ured <30 mm. For maxillary arches, 3.4% are less than 30 mm and 38.8% are less than 35 mm from cuspid to cuspid. The differences between male and female intercuspid distance averaged 1.6 mm for the maxilla and 1.0 mm for the mandible, but there was considerable overlap. Racial and age differences over the age of 12 were also insignificant [24]. Thus race, gender, and age cannot be predicted from an adult bitemark. The entire adult bitemark injury usually measÂ�ures in width from 3.5 to 4.0 cm when a full complement of anterior teeth is involved. Its length, measÂ�ured from upper to lower incisors, varies with degree of jaw opening and amount of skin gathered during the bite. The average maximal opening diameter is ∼42–45 mm but can exceed 70 mm. The amount of skin gathered will be less on flat, taut surfaces than on curved or pliable surfaces such as extremities, breasts, and buttocks. The dynamics of biting usually cause the mandibular bitemark to appear more intense and more sharply defined than the maxillary. This has been attributed to the fact that the lower is the movable jaw or, as Sperber opined, that the skin contacting the upper teeth during biting is not squarely pressed against the incisal edges

3.5–4.0 cm

Figure 5.2â•‡ Diagram of a prototypical human bitemark showing class characteristics.

as in the lower, but rather along the broad slope of the lingual surfaces of the overlapping upper teeth [25]. The idealized bitemark is diagramed in FigureÂ€5.2. The value of defining class characteristics for the human bite is twofold: First, it defines objective criteria upon which to distinguish the human bite from other patterned injuries; second, the data suggest that many bitemarks will be similar based on shared characteristics and that a “match” between a bitemark and suspect based on these nonspecific class characteristics does not necessarily “identify” the biter. A bitemark with a maxillary and mandibular intercuspid distance of 34 and 25 mm, respectively, 9.0-mm maxillary central incisors, 5.6-mm mandibular incisors, and aligned arches will accommodate a large percentage of human dentitions. Bites inflicted by children also bear class characÂ� teristics that define this subset. Compared to adult teeth, the deciduous dentition of children below the age of 6 years typically features smaller, rounded, bowlike arches; smaller teeth; and spacing between teeth. Upper central incisors, at an average mesiodistal width of 6.5 mm, are only slightly larger than lateral incisors at 5.3 mm. Lower incisors measÂ�ure about 4–4.5 mm [21,26]. The mean maxillary intercuspid distance measÂ� ures 28–29 mm from ages 3–6 years, and the mean mandibular intercuspid distance is ∼22.6 mm. This is about 4.4 and 2.5 mm smaller than the respective intercuspid distances of adults [23]. Reflecting these attributes, bitemarks from children are typically smaller than adult bitemarks (3–3.5 cm), with spaces between the teeth (FigureÂ€ 5.3, left). Marks from the upper centrals are only slightly larger than other incisors. Children between the ages of 7 and 11 have a mixed dentition, which effaces the anterior spacing once the larger permanent incisors erupt. This causes the anterior segment to widen while the narrower posterior segments are relatively constricted lingually [26].

The Nature of Bitemarks

57

Figure 5.3â•‡ Typical bitemark from a child showing small, spaced teeth (left). Bitemark showing central contusion

with pale area from tongue thrusting (right). Note continuous ring due to approximation of maxillary and mandibular arches.

5.8â•…Variations of Bitemark Patterns Unfortunately, a well-inflicted, undistorted bitemark showing 12 or more teeth is uncommonly seen. There are variations in bitemark morphology due to additional injury patterns sustained during the dynamics of biting as well as degradations and deficiencies due to distortion or partial recording. 5.8.1â•…Central Contusion A central area of contusion or ecchymosis is frequently noted within the confines of the bite (FigureÂ€5.3, right). In the past, this has been attributed to suction with or without the pressure of tongue thrusting, and its etiology has been ascribed to prolonged, sadistic, sexual biting activity. Today the pathogenesis for central contusion is attributed to the compression of tissue squeezed in between the upper and lower teeth causing rupture of capillaries. The mechanism was witnessed at the 1984 ABFO Bitemark Workshop when a set of models on an articulator compressed abdominal tissue of a volunteer,

causing an instant and intense central bruise. There was no possible suction. The literature persists in calling these bruises “suck marks” [8] with the implication of a sexual motivation— an inappropriate deduction. Both mechanisms (positive and negative pressure) contribute to central contusions. The appearance of central contusion is not helpful in identifying a biter since it is nonpatterned and not made by teeth. However, it does help support that the lesion represents a bitemark. (Editor’s note: See Section 21.10.19 in Chapter 21.) 5.8.2â•…Linear Abrasions and Contusions A series of linear abrasions or contusions is often found radiating at right angles to the arches external to the periphery of the bitemark. These represent the action of teeth scraping as they slip across skin during closing or as the victim attempts to pull free. These “drag marks” distort the anatomy of the teeth and are not welcome in terms of biter identification, but they do help corroborate the nature of the injury as a bite (FigureÂ€5.4).

Figure 5.4â•‡ Drag marks left by mandibular teeth scraping across face (left). Three drag marks in a bitemark made by mandibular left teeth (right).

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

5.8.3â•…Lingual Markings Occasionally, short linear or gumdrop-shaped patterns appear centripetally, radiating inward from the arches. These represent the outlines of the lingual surface of teeth. Entire outlines of embrasures, gingival margins, and papillae can be reproduced. Harvey attributed these markings to tongue thrusting in which the tongue pressed the captured skin against the teeth [9]. Noting that lingual markings were more common on upper teeth, Sperber related their presence to pressing of skin by lower teeth against the lingual surfaces of overlapping upper teeth when bites were inflicted in a centric relationship [25]. Other potential factors contributing to lingual markings include soft skin, thin skin supported by adipose, and labially inclined anterior teeth. The pressure of the lingual surfaces does not have to be great to register markings; some lingual markings may not represent a wound at all but rather an area of sparing when central contusion follows a path of least resistance and flows into skin adjacent to the skin compressed by the cingula and marginal ridges of the incisors. The incisor imprints appear pale, outlined by thin, red tracts of contusion where relief was afforded by embrasures and gingival soft tissue (FigureÂ€ 5.5). (Editor’s note: See Section 21.10.8 in Chapter 21.) 5.8.4â•…Tongue Thrusting The tongue can leave a pale area within a central contusion where its pressure against the skin either forced out or failed to admit the blood extravasated during central contusion formation (FigureÂ€5.3, right). (Editor’s note: This phenomenon has been produced experimentally with mounted

dental casts and is therefore not necessarily produced by tongue thrusting. See Section 21.10.19 in Chapter 21.) 5.8.5â•…Acute Inflammatory Reaction A bitemark may show the hallmarks of acute inflammation within minutes of infliction. This includes the wheal and flare reaction, where redness and swelling predominate. The bitemark appears diffusely erythematous and slightly raised. The ring appearance may be replaced by a solid red oval, obliterating arches and tooth marks. The acute reaction subsides within hours to a day, restoring the identifying class characteristics [15]. Such events are most common on children’s faces (FigureÂ€5.6). 5.8.6â•…Uninterrupted Arches Most bitemarks show a separation between the maxillary and mandibular arches, representing the unbitten skin that curves between two arches. If the skin is sufficiently thin and the bite force is intense, the upper and lower teeth at the posterior margin of the bite can nearly approximate, causing a continuous, uninterrupted ring of tooth marks representing both arches. Since similar patterns can be made by oval and round objects like rings, care must be exercised in designating an origin from such patterns. 5.8.7â•…Tooth Indentations Actual depressions representing impressions of teeth in skin do occur at the moment of biting and do not require much force. Because of the elastic memory of skin and the swelling that might occur in the acute phase, these

Figure 5.5â•‡ Lingual markings formed when pressure from mandibular cingula prevented spread of central contusion (left). (From ABFO Bitemark Workshop.) Five maxillary and five mandibular teeth recorded as lingual markings (right).

The Nature of Bitemarks

59

Figure 5.6â•‡ Acute inflammation and swelling account for solid appearance of bitemarks photographed within hours of infliction (left). The same bitemarks as in the left-hand figure, photographed a day later when subsiding inflammation revealed the ring pattern of arches (right).

indentations usually smooth out within 20 minutes and are seldom available for evaluation (FigureÂ€5.7). (Editor’s note: See Chapter 21 for many examples of this condition.) 5.8.8â•…Double Bite Literally a bitemark within a bitemark, this variant occurs when a mass of skin captured between teeth is grasped and the victim partly pulls free, followed by a reapplication of biting force. The result is two concentric sets of arches with duplication of the bite pattern. AccompanyÂ� ing drag marks might be seen (FigureÂ€5.8, left). (Editor’s note: This phenomenon has been produced experimentally with mounted dental casts and is therefore not necessarily produced by the victim pulling free. See Chapter 21 for many examples of double and superimposed bites.) 5.8.9â•…Multiple and Superimposed Bites Two or more bites are found in 40–48% of bitemark cases [19,20]. Multiple bites made by the same biter allow

Figure 5.7â•‡ Temporary indentations of teeth in a bitemark photographed minutes after infliction.

Figure 5.8â•‡ “Double bite” occurring as teeth slipped, followed by reapplication of force, creating concentric duplication of pattern.

the odontologist to search for reproducible patterns among the bites that can then be considered nonartifactual stable characteristics (FiguresÂ€5.8, right, and 5.9). Superimposed bites, on the other hand, can confound bitemark analysis because they overlap and degrade detail (FiguresÂ€ 5.8, right, and 5.10, left). (Editor’s note: See Chapter 21 for many examples of this condition.)

Figure 5.9â•‡ (A) Multiple bites in a gunshot homicide victim. Superimposed bites and two single bites are seen.

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 5.9â•‡ (B,C) Close-up of bitemarks seen in Figure 5.9A. Bitemark medial to axilla shows a suggestion of distinctive

individual characteristics (B). Repetition and improvement in pattern seen in bitemark posterolateral to axilla (C). Note severe labial crowding and rotation of number 27; overlapping of numbers 26, 25, and 24 (Universal System), and drag marks of entire anterior maxillary arch.

5.8.10â•…Weave Patterns Bitemarks through clothing can leave the weave pattern of the fabric embossed in contusion. Clothing can also dull or eliminate the detail of tooth marks and prevent saliva and DNA deposition, which must then be obtained from the garment (FigureÂ€5.10, right). (Editor’s note: See Chapter 21 for many examples of this situation.) 5.8.11â•…Excessive Ecchymosis and Abrasion Excessive bleeding outside the confines of the bitemark can obscure pattern details and cause the bitemark to appear larger than normal. Secondary injury unrelated to biting, such as holding of the part being bitten, may account for some examples. Ostensibly, biting of previously injured skin can cause peculiar patterns. Levine reported a case in which the biter inflicted abrasions in an attempt to obliterate the bite pattern [7]. Excessive bleeding is also encountered in those who bruise readily (females, elderly, children, thin skin, skin supported by adipose, and patients on steroids, on anticoagulants, or with coagulopathies or liver disease). Care is necessary to find the characteristic arch form and tooth

marks so that the injury can be properly identified (FigureÂ€5.11, left). 5.8.12â•…Partial Bitemarks If skin is not squarely bitten, only portions of the dentition mark. Resulting variants include unilateral (onesided) bitemarks (FigureÂ€5.11, left) in which only the left or right side of both arches marks, one-arched bitemarks (FigureÂ€5.12, left) showing only an upper or lower arch, or bitemarks showing only a few teeth (FigureÂ€5.12, right). Unilateral bitemarks occur when the bite is skewed or the anatomy of the bitten tissue curves away from the teeth on one side. Bitemarks showing few teeth can be due to a poorly inflicted bite, superimposed clothing, highly curved skin contours, variations in underlying skin support within the bitten tissue, or missing teeth in the biter. Single-arched bitemarks are most likely to be disputed. Logic predicts that both arches are needed to produce the required pressure; however, bitemarks with one arch have been documented, despite the fact that the biter had a full dentition [7]. Interposed clothing or foreign object, dull surfaces of teeth, variations in skin and

Figure 5.10â•‡ Two superimposed bites converging at the nipple (left). Linear arrangement of tiny contusions reflecting the weave pattern in the sweater in this bitemark through clothing (right).

The Nature of Bitemarks

61

Figure 5.11â•‡ Excessive hemorrhage surrounding bitemark (left). Partial bitemark created by left maxillary and mandibular arch (right). (Both photos courtesy Dr. William Smock.)

Figure 5.12â•‡ One arched bitemark (left). (From ABFO Bitemark Workshop.) Bitemark showing only two maxillary and two mandibular incisors (right).

skin support, or more rapid fading of one arch (usually the upper) can account for single-arched marks. Falling or lying upon a removable denture has produced a onearched bite pattern [16]. 5.8.13â•…Indistinct or Faded Bitemarks “Toothless” bitemarks frequently appear. The class characteristic of facing arches is present, but individual teeth are not seen. There may be a suggestion of scalloping, indicating a fusion of indistinct tooth marks or merely a uniform contusion with little or no abrasion. Such bitemarks occur when the collective pressure of teeth within an arch leaves a continuous curved contusion. This is most often seen in soft, yielding skin (children, women) and skin cushioned by abundant adipose, which is very vascular and easily bruised. It also occurs as bitemarks heal. An otherwise well-defined bitemark can show fading of the tooth marks before the background contusions (FigureÂ€5.13).

5.8.14â•…Avulsive Bites Severe, vicious bitemarks can lacerate and avulse tissue to the point of loss of soft tissue. This results in gaping wounds that are not readily identifiable as bitemarks and rarely permit identification of a perpetrator. Avulsive bites, common in dog maulings, are infrequent in human bites. They are most apt to occur on projecting anatomic areas such as nipples, noses, ears, fingers, genitals [9,15,27], or tongues (FigureÂ€5.14, left). 5.8.15â•…Healed Bitemarks Any injury can heal with more, less, or the same amount of melanin as the surrounding skin. Increased melanin is known as postinflammatory pigmentation. Decreased melanin is seen in some scars. Both phenomena are more readily appreciated in dark-pigmented individuals. These pigmentary changes may maintain the pattern of a bitemark for many months (FigureÂ€ 5.14, right).

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

appear yellow, translucent, and parchmentlike [28]. It should be noted that a severe blow inflicted within a few hours of death might produce contusions [29]. (Editor’s note: I have produced 34 postmortem bites experimentally from 1 minute to several days after death and have never been able to create a postmortem contusion at the bite site. See Chapter 21 for many examples of this situation.)

5.9 Individual Characteristics of the Human Bitemark

Figure 5.13 Toothless bitemarks showing only arch form and size as class characteristics.

Sometimes the pigmentary patterns are too subtle to be seen visibly and are present as latent injuries that can be imaged only by ultraviolet photography. 5.8.16 Postmortem Bitemarks Bitemarks created after death do not show the vital responses that facilitate visualization of the injury. Post mortem abrasions lack the scab composed of serum, fibrin, and red blood cells formed in a living subject. They

An individual characteristic is a feature or pattern that represents a departure from an expected finding within a defined group. It represents an individual variation that serves to identify a particular member of the group. A tear or wear pattern in a tire or shoe sole that imprints in a tread mark or footprint is an example. For bitemarks, a tooth malposition or diastema can produce individual characteristics. Such characteristics are due to a combination of genetics and environment. When seen in bitemarks, individual characteristics allow the forensic dentist to eliminate, narrow down, or identify suspects depending on the bitemarks’ degree of distinctiveness.

5.10 Dog Bites Large dogs, most notably rottweilers, pit bulls, chows, German shepherds, and Doberman pinschers, account for most serious or fatal bites in the United States. Canine dentitions show considerable variations among breeds with regard to tooth and arch size and arch shape. Dogs such as collies and Doberman pinschers have long

Figure 5.14 Avulsed human bitemark in soft tissue above the eyelid (left). (Courtesy of Dr. William Smock.) Old healed bitemark showing postlesional pigmentation (right). (Courtesy of Dr. Richard Souviron.)

The Nature of Bitemarks

63

Figure 5.15â•‡ Occlusal views of the canine dentition. Note constriction of arch posterior to the cuspid followed by flaring beginning in the premolar region (left). Flared mandibular cuspids fit into perforations in this dog bite. Note concordance of incisor injuries to the arrangement and anatomy of incisor teeth (right).

Figure 5.16â•‡ Dog bite showing constriction and flaring of mandibular arch including molar teeth (left). Dog claw marks across back of victim of dog mauling (right).

muzzles, while rottweilers, chows, and pit bulls have wider arches. Yet, in spite of variations, there are defining class characteristics that allow identification of a bitemark as a dog bite. The canine dental formula is I3/3, C1/1, P4/4, M2/3 (FigureÂ€5.15, left). Each arch has six small incisors aligned in a gently curved arch. Following a space (largest in the maxilla), two long, pointed cuspids are positioned at the corners of the arch; at this point the arch turns sharply posteriorly. Beyond the cuspids, there is a space followed by a small first premolar. The second, third, and fourth premolars are spaced and become increasingly larger. The first molar is the largest molar, followed by progressively smaller molars. Dogs and other carnivores possess tritubercular posterior teeth in which premolars and molars have three aligned cusps or tubercles forming a triangle [26]. Upper and lower cusps slide past and interlock with each other during biting, allowing these teeth to grasp and lacerate. The well-inflicted dog bite shows a long, narrow arch compared to a human bite. The small incisors may

not produce markings, but if all six incisors of an arch mark, they serve to exclude a human bite. The long, fanglike cuspids produce prominent markings—often deep punctures or lacerations that may not conform to the intercuspid distance of the bites since dog canines flare occlusally (FigureÂ€5.15, right). The bitemark turns sharply posteriorly to the cuspids, converges lingually, and then flares buccally. Premolars and molar markings are common since the dog’s jaws can open widely (FigureÂ€5.16, left). In a defensive or anger bite, a dog may snap and let go. In these bites, anterior tooth marks predominate and can show superficial similarity to a human bite. In a mauling or predatory bite, the dog will grasp a large segment of tissue using posterior teeth and, by pulling and shaking, cause drag marks and lacerations. If the grip loosens, the dog attempts to thrust its head forward to seize more tissue, thus creating double or superimposed bites. Laceration and avulsions caused by large carnivores can be so sharply defined as to be mistaken for incisions. Accompanying long abrasions from claws

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Figure 5.17â•‡ Bite pattern of mandibular anterior teeth deliberately recorded in chewing gum by a clever rape victim during her incarceration in the trunk of a car. The gum was left in the car to confirm her ordeal (left). Tooth marks left in a hardwood church collection plate used to beat the face of a victim of traumatic death (right).

may be seen in some cases (FigureÂ€5.16, right). (Editor’s note: See Chapters 16 and 17.)

5.11â•…Bitemarks in Other Substrates Food and other compressible objects record a bitemark in the same manner as impression material; accuracy is determined by the substrate and its tendency to deform, dehydrate, or decompose following the bite. Foods like cheese, chewing gum, cake icing, and chocolate and other candy can produce useable threedimensional impressions under favorable conditions (FigureÂ€ 5.17, left). Fruits, vegetables, butter, and preserved meats can also record identifiable bitemarks but with more opportunity for distortion. Tooth indentations have also been recorded in wood and plastic (FigureÂ€5.17, right).

References 1. American Board of Forensic Odontology. 1995. ABFO bitemark terminology guidelines. Seattle, WA: American Board of Forensic Odontology. 2. Sweet, D. J., R. Dorion, J. C. Dailey, A. F. Shernoff, J. H. W. Gelles, D. Spencer, and T. J. David. 1995. Bitemark evidence. In Manual of Forensic Odontology, 3rd ed., ed. C. M. Bowers and G. L. Bell, 148–190. Colorado Springs, CO: American Society of Forensic Odontology. 3. Sopher, I. M. 1976. Forensic dentistry, 125–152. Springfield, IL: Charles C Thomas. 4. Gladfelter, I. A. 1975. Dental evidence: A handbook for police, 31–47. Springfield, IL: Charles C Thomas. 5. Stimson, P. G., and C. A. Mertz. 1997. Bite mark techniques and terminology. In Forensic dentistry, ed. P. G. Stinson and C. A. Mertz, 137–159. Boca Raton, FL: CRC Press.

6. Levine, L. J. 1982. Bitemark evidence. In Outline of forensic dentistry, ed. J. A. Cottone and S. M. Standish, 112–127. Chicago, IL: Year Book Medical Publishers. 7. Levine, L. J. 1977. Bitemark evidence. In The dental clinics of North America—Symposium on forensic dentistry: Legal obligations and methods of identification for the practitioner, ed. S. M. Standish and P. G. Stimson, 145– 158. Philadelphia, PA: W. B. Saunders Company. 8. Clark, D. H. 1992. Practical forensic odontology, 128–205. Oxford, England: Wright. 9. Harvey, W. 1976. Dental identification and forensic odontology, 88–140. London: Henry Kimpton Publishers. 10. Luntz, L. L., and P. Luntz. 1973. Handbook for dental identification: Techniques in forensic dentistry, 148–162. Philadelphia, PA: J. B. Lippincott Company. 11. Gustafson, G. 1966. Forensic odontology. London: Staple Press. 12. Cameron, J. M., and B. G. Sims. 1974. Forensic dentistry, 129–145. Edinburgh: Churchill Livingstone. 13. Sobel, M. N., and J. A. Perper. 1985. Self-inflicted bite mark on the breast of a suicide victim. American Journal of Forensic Medicine and Pathology 6 (4): 336–339. 14. Warnick, A. J., L. Biedrzycki, and G. Russanow. 1987. Not all bite marks are associated with abuse, sexual activities or homicides: A case study of a self-inflicted bitemark. Journal of Forensic Sciences 32 (3): 788–792. 15. Whittaker, D. K., and D. G. MacDonald. 1989. A color atlas of forensic dentistry, 108. Ipswich, England: Wolfe Medical Publications Ltd. 16. Levine, L. J. 1971. Forensic odontology. International Microform Journal of Legal Medicine 1971; 6 (3, Card 5B4–13). 17. Vale, G. L. 1986. Bite mark evidence in the investigation of crime. California Dental Association Journal 14 (3): 36–42. 18. Rawson, R. D., A. Koot, C. Martin, J. Jackson, S. Novosel, A. Richardson, and T. Bender. 1984. Incidence of bite marks in a selected juvenile population: A preliminary report. Journal of Forensic Sciences 29 (1): 254–259.

The Nature of Bitemarks 19. Pretty, I. A., and D. Sweet. 2000. Anatomical location of bitemarks and associated findings in 101 cases from the United States. Journal of Forensic Sciences 45 (4): 812–814. 20. Vale, G. L., and T. T. Noguchi. 1983. Anatomical distribution of human bite marks in a series of 67 cases. Journal of Forensic Sciences 28 (1): 61–69. 21. Moorrees, C. F. A., D. Thomsen, E. Jensen, and P. K. Yen. 1957. Mesiodistal crown diameters of the deciduous and permanent teeth in individuals. Journal of Dental Research 36 (1): 39–47. 22. Rawson, R. D., R. K. Ommen, G. Kinard, J. Johnson, and A. Yfantis. 1984. Statistical evidence for the individuality of the human dentition. Journal of Forensic Sciences 29 (1): 245–253. 23. Moorrees, C. F. A. 1959. The dentition of the growing child: A longitudinal study of dental development between 3 and 18, 92–106, 203. Cambridge, MA: Harvard University Press.

65 24. Barsely, R. E., and D. M. Lancaster. 1987. Measurement of arch widths in a human population: Relation of anticipated bite marks. Journal of Forensic Sciences 32 (4): 975–982. 25. Sperber, N. D. 1990. Lingual markings of anterior teeth as seen in bite marks. Journal of Forensic Sciences 35 (4): 838–844. 26. Ash, M. M., and S. J. Nelson. 2003. Wheeler’s dental anatomy, physiology and occlusion, 8th ed., 75, 101–102, 160, 168, 181, 188. Philadelphia, PA: W. B. Saunders Company. 27. Rawson, R. D. 1986. Child abuse identification. California Dental Association Journal 14 (3): 21–25. 28. DiMaio, D. J., and V. J. M. DiMaio. 2001. Forensic pathology, 2nd ed., 92–104. Boca Raton, FL: CRC Press. 29. Robertson, I., and R. A. Mansfield. 1957. Antemortem and postmortem bruises of the skin: Their differentiation. Journal of Forensic Medicine 4:2–10.

Reconstructive Bitemark Analysis Mark L. Bernstein

6

Contents 6.1 Organizational Construction for Initial Analysis 6.2 Quality of the Bitemark 6.3 Profiling the Biter 6.4 Maintaining Perspective 6.5 Summary References

67 67 68 69 70 70

6.1â•…Organizational Construction for Initial Analysis

to a criteria-based goal or standard, the exercise may be more meaningful. There are two quality assessments. The first simply allows a measÂ�ure of confidence that the patterned injury is a bitemark and can be expressed as the ability of the pattern to reproduce the class characteristics of the human bite. The second measÂ�ure is intended to communicate the anticipated evidentiary value of the bitemark in perpetrator identification. In this case, both class and individual characteristics must be evaluated. A bitemark deemed to be of exceptional quality would show the idealized class characteristics recorded in a distortion-free pattern. The incisal edges of individual teeth would be outlined and distinct, unencumbered by drag marks, superimposed distractions, or inaccuracies caused by skin elasticity. Each tier of specificity (identification as a bitemark, discrimination of animal vs. human, adult vs. child, and upper vs. lower arch) would be determinable. For the second measÂ�ure of quality, more is needed. Individual characteristics would have to show sufficient quantity or deviation from the norm so as to constitute a distinctive or unique pattern. All things being equal, the greater the quantity of features in a bitemark, the more opportunity there is for higher biter discrimination. However, the quantity of participating teeth is not as important as their degree of abnormality. Six wellaligned teeth in an arch will render a bitemark of less quality than one with fewer teeth if some are malposed. Similarly, since arch size and shape are relatively consistent among people, only clearly deviant arches would add quality to the bitemark. A bitemark is considered to be poor or marginal in quality when the tooth marks are absent, uncertain, smudged, indistinct, faded, or distorted to the extent that incisal edge morphology is effaced. Partly inflicted tooth marks or sparse marks that fail to show a relationship between adjacent teeth also degrade the value of the bitemark.

Routinely, when called to examine a patterned injury, the odontologist follows a standard protocol, asking a series of increasingly specific questions: Is it a bitemark? Is it human or animal? Can it be ascribed to an adult or a child? Can upper and lower arch be discriminated for orientation purposes? Are there individual characteristics that help to profile the biter’s dentition? Are the bitemarks ante- or postmortem? The answer to each question is neither intuitive nor based on an educated guess, but rather derives from the fulfillment of criteria that can be explained, demonstrated, and justified. In a well-inflicted, characteristic bitemark, these determinations can be made.

6.2â•…Quality of the Bitemark Determining the quality of a bitemark is an exercise that is performed in the reconstructive phase, prior to a comparison of suspect casts. The individual criteria used to determine quality are objective, yet an overall appraisal of quality is an algorithmic judgment based on these criteria. Many odontologists assign a quality rating to bitemarks. Since the standards for quality have not been formalized among odontologists, each investigator is apt to make subjective or objective assessments based on personal criteria. This has the potential for inconsistent determinations and miscommunications. If bitemark quality is defined as an assessment of value referenced 67

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Bitemarks showing features intermediate in value between these two extremes may be considered of good or fair quality. Thus, the discriminating value of any individual characteristics has to be weighed against the minimizing effect of any distortions or deficiencies. Well-inflicted bitemarks that are clear and distinct yet lack individual characterization may also be considered excellent in quality for assignment as a human bitemark, although conditional for assailant identification. Although odontologists rarely disagree on interpretations of exceptional or poor-quality bitemarks, judging the value of good- or fair-quality bitemarks is more inconsistent. There are no guidelines to assist odontologists in reliably constructing a precise hierarchy of bitemark quality. ABFO bitemark terminology guidelines [1] specify only two terms: bitemark (indicating that teeth created the pattern) and suggestive (inconclusive, missing or distorted tooth marks or arch configuration). The initial assessment of bitemark quality should serve only as a guide to approaching the case rather than a formal and final determination. Other investigations may impact this initial judgment. Transillumination of the bitemark; photographic studies in ultraviolet (UV), infrared (IR), or alternate light imaging (ALI); scanning electron microscopy; and computer enhancement are only a few of the tertiary techniques that may add information to elevate the quality of the bitemark. The finding of other bitemarks on the body enhances the value of each component bitemark because individual features can be cross-referenced among the bitemarks to determine their stability and reliability (providing it can be determined that they were inflicted by the same person).

6.3â•…Profiling the Biter It is tempting to “read” a bitemark and make predictions about the teeth that produced it, but this can be a

two-edged sword. Levine [2,3] urged against profiling, cautioning that bitemark patterns can “defy logic.” Bush et al. [4] and Dorion [4,5] warn that bitemark patterns can produce unexpected results. A space in a bitemark might merit a spurious comment such as “look for a person with a missing tooth or a space between teeth,” only to be discredited when the tooth is present in the biter. The reason for its not appearing could be that it was chipped, did not reach the occlusal plane, was blunted, was loose, was buffered by superimposed clothing, or that Langer’s lines contributed to the illusion of its absence. Skin factors such as folding during the bite and lack of bony support can account for a tooth not leaving a mark (FigureÂ€6.1). Likewise, if individual teeth in a bitemark are not clearly identifiable or if maxillary and mandibular arches cannot be discriminated with certainty, these “educated guesses” as to origin should not be communicated informally or in a report. Such speculation can be the odontologist’s albatross. Bush et al. [4] reported that 38% of experimentally produced bitemarks on cadavers showed distortions that did not conform to the biter’s dentition and might be incorrectly interpreted. About half of these related to arch size or curvature. On the other hand, a prediction that correctly identifies an unusual characteristic in a suspect inspires confidence in the odontologist because it is objective and criteria based. This must be done with caution. For example, an experienced odontologist might reasonably predict a severely malposed incisor because of a repetitive arch irregularity seen in several well-inflicted, nondistorted bitemarks. It is better to make such predictions in a nonspecific fashion—for example, a prediction of an “anatomic abnormality expected in the biter’s upper central incisors” rather than “look for someone with shovelshaped incisors.” Profiling a dentition is not an a priori fact and is not intended to initiate a search for a suspect in an open population. Rather, it should be used to check

Figure 6.1â•‡ Witnessed bitemark of a child showing apparent “missing” maxillary central incisors (left). The biter (right) has nonmobile central incisors that did not imprint because the skin was folded and clothed during the act of biting.

Reconstructive Bitemark Analysis

69

the odontologist’s veracity prior to his or her examination of dental evidence on a viable suspect.

6.4â•…Maintaining Perspective When an odontologist is asked to inspect a pattern in an injury or object, he or she will formulate an initial assessment by applying the criteria reviewed in this chapter. Some patterns will fulfill enough criteria to merit distinction as a bitemark or be suggestive of a bitemark. Others will simply fail to reach a threshold of characteristics that would allow a designation of bitemark, let alone perpetrator identification. The odontologist is advised not to dismiss such injuries automatically. Even bitemarks deemed to be of poor or marginal quality have proven to be relevant. A poorly or partially registered tooth-to-substrate mark might have saliva trace evidence sufficient for perpetrator identification. Similarly, identifiable bitemarks that lack individual characteristics should be given full attention and photographic documentation. The manner in which the case unfolds might make such a bitemark critical evidence. As mentioned earlier, a nondescript bitemark helps support the nature of some crimes even if it cannot implicate a particular perpetrator. A final determination of usefulness of a bitemark must consider the comparison of suspects’ teeth. In some crimes, particularly child abuse cases, it might be shown that only a limited number of people had opportunity to bite [3]. A nondescript bitemark in such a case could be used to rule out individuals if there are gross and unexplainable discrepancies or to

Figure 6.2â•‡ This toothless bitemark is nondescript except for its relatively small, rounded arches.

implicate a suspect by exclusion of all others (FiguresÂ€6.2 and 6.3). Even an injury that mimics a bitemark should be fully documented and analyzed by a forensic odontologist. If such a lesion is disregarded because it is attributed to some other cause, opposing attorneys could capitalize on such a mark by identifying it as a bitemark that does not match the dentition of the accused. In some cases, a biter’s dentition might be so aberrant that his or her bitemark is unrecognizable as such and is overlooked. Failure to document such an injury could be a missed opportunity to record a unique pattern that would have generated convincing assailant identification. As is evident from these examples, the initial assessment of evidentiary value of a bitemark might have to be modified once the comparison is performed.

Figure 6.3â•‡ Overlay of a suspect’s arch on bitemark in preceding figure shows nonspecific similarity (left). Overlay of a

second suspect’s arch on the bitemark shows incompatible arch size and form (right). Three other suspects were similarly eliminated. The dentition in the preceding figure was identified as the biter by exclusion.

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6.5 Summary Bitemarks are patterned injuries or impressions in substrates that can be relevant in the determination of the nature of crimes and the identification of perpetrators. The collective wisdom of odontologists gained over 35 years of judicious and organized study of bitemarks has provided objective criteria upon which to evaluate these patterns. The subject is complex, and fastidious techniques must be applied both technically and analytically. Simple errors of analysis, such as confusing upper and lower arch or failing to remember that a bitemark is a mirror image of the dentition, can cause catastrophic miscalculations that place the fate of suspects, the legal system, the discipline of bitemark analysis, and the individual odontologist in peril. Because the odontologist can never anticipate the outcome of a given case, all patterned injuries or markings of questioned dental origin should be treated as bitemarks and processed accordingly, whether or not the odontologist initially suspects etiology from teeth. This also applies to nondescript injuries in which a victim claims to have been bitten.

References 1. American Board of Forensic Odontology. ABFO bitemark terminology guidelines. Seattle, WA: American Board of Forensic Odontology 1995. 2. Levine, L. J. 1982. Bitemark evidence. In Outline of forensic dentistry, ed. J. A. Cottone and S. M. Standish, 112– 127. Chicago: Year Book Medical Publishers. 3. Levine, L. J. 1977. Bitemark evidence. In The Dental Clinics of North America—Symposium on forensic dentistry: Legal obligations and methods of identification for the practitioner, ed. S. M. Standish and P. G. Stimson, 145–158. Philadelphia, PA: W. B. Saunders Company. 4. Bush, M. A., H. I. Cooper, and R. B. J. Dorion. 2010. Inquiry into the scientific basis for bitemark profiling and arbitrary distortion compensation. Journal of Forensic Sciences 55:976–983. 5. Dorion, R. B. J. 2010. Bite mark profiling based upon color, UV, and ALI photographic interpretation. Proceedings of the 62nd annual meeting of the American Academy of Forensic Sciences, Feb. 22–27, 2010, Seattle, WA. Colorado Springs, CO: American Academy of Forensic Sciences.

Collection of Bitemark Evidence A: Noninvasive Analyses

IV

7

Photography Gregory S. Golden Franklin D. Wright Contents 7.1 Introduction 7.2 Electromagnetic Spectrum: What It Means to Forensic Photography 7.2.1 Reflection 7.2.2 Absorption 7.2.3 Fluorescence 7.2.4 Diffusion 7.2.5 Summary 7.3 Conventional (Visible Light) Photography 7.4 Digital Photographic Systems 7.4.1 Professional, Pro-sumer, and Consumer Cameras 7.4.2 Lenses 7.4.3 Flash Accessories 7.4.4 Digital Video Cameras 7.5 Forensic Photographic Protocol 7.5.1 Photographic Scales 7.6 Visible Spectrum Imaging 7.6.1 Visible Imaging Technique 7.7 Digital Image Acquisition 7.7.1 Image Capture Sensors 7.7.2 Pixels and Color 7.7.3 Aspect Ratio 7.7.4 Resolution and Compression 7.7.5 ISO Equivalence 7.7.6 Lens Magnification 7.7.7 Storage Devices 7.7.8 Saving Digital Images 7.7.9 Digital Scanners 7.8 Considerations for Digital Photography in Order of Importance 7.8.1 Alternate Light Imaging 7.8.2 Digital ALI Technique for Bitemark Photography 7.9 Nonvisible Light Photography: Infrared Technique 7.9.1 Armamentarium for Digital Infrared Photography 7.9.2 Infrared Photography Technique 7.9.3 Focus Shift 7.10 Reflective Ultraviolet Digital Photography 7.10.1 Ultraviolet Digital Photography Armamentarium 7.10.2 Digital Ultraviolet Protocol 7.11 Application of Photographic Techniques Other Than for Bitemarks References

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74 74 75 75 77 77 77 77 77 78 79 80 80 80 81 81 82 82 83 83 84 84 85 85 86 86 87 87 89 91 94 95 95 96 96 97 98 98 102

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

7.1â•…Introduction As the fundamental principles of forensic photography have sustained the test of time, digital imaging has elevated forensic photography into a completely new and profoundly different discipline. Changes and improvements occur on a regular basis. One needs simply to compare the first edition of this textbook to the current writing. Consequently, any treatise or chapter that addresses current levels of photo technology and imaging risks obsolescence by the time publication places it into the public domain. The technology of digital imaging is expanding that rapidly. What the authors hope to accomplish in this chapter on advanced digital photographic methods is to provide the reader with the fundamental building blocks necessary to understand each method’s protocol, the variations among techniques, and their applications in bitemark documentation. The primary intent is to convey the information necessary to allow anyone with a basic comprehension of photography to document what happens biologically in injured tissue. A discussion of equipment requirements for each technique will be included as well as an explanation of why certain parts of the visible and nonvisible spectrum produce images of the same bitemark that appear entirely differently from each other. The authors’ mutual goal is to assist the reader in ultimately becoming a better photographer, thereby improving his or her proficiency in capturing accurate photographic images of bitemark evidence. It is beyond the scope of this chapter to teach the basic fundamentals of photography. Many high-quality Ultraviolet

λ nm

introductory photography textbooks have been written and are readily available at book and photography stores. This chapter takes information from the basics of photography and integrates it with the special technical requirements associated with forensic photography. Unless otherwise specified, the scientific data and techniques described in this chapter apply to forensic bitemark photography and skin injuries.

7.2â•…Electromagnetic Spectrum: What It Means to Forensic Photography A significant portion of the electromagnetic spectrum extends from very short wavelength ultraviolet light in the 200-nm range through the visible light range of 400–700 nm into the infrared range of 700–900 nm (FigureÂ€7.1). A nanometer (nm) is one billionth (10–9) of a meter. Since the human eye cannot capture light outside the visible range, special photographic techniques using ultraviolet and infrared light have been developed for this purpose [1]. With varying light wavelengths illuminating the photographed object, very different appearances of the object can be portrayed. This is especially relevant in documenting patterned injuries such as bitemarks, tool marks, stab and gunshot wounds, fingernail scrapes, etc. These techniques can facilitate recognition of damaged tissue from adjacent normal tissue. Ultimately, a more complete and comprehensive collection of photographic evidence is obtained (FigureÂ€7.2). When full-spectrum light strikes skin, four resultant events occur: reflection, absorption, diffusion, and Visible

200

300

400

500

600

Infrared

700

800

900

Epidermis

Dermis

Subcut.

Figure 7.1â•‡ Penetration of light into skin with different wavelengths of the electromagnetic spectrum.

Photography

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Figure 7.2â•‡ Color (upper left); black and white desaturated in Photoshop (upper right); UV digital image. Fujifilm IS-Pro,

Nikon quartz UV 105 lens, ISO 1600, F/4, 1/60 second, sRGB, Nikon SB 140—full flash, Baader Venus U filter (lower left); monochrome (UV) digital image desaturated in Photoshop (lower right) photograph of a bitemark on the leg. (Courtesy of the San Bernardino County Sheriff’s Dept.)

fluorescence [2]. By changing the wavelength of the incident light, each of these four possible effects can be emphasized to reveal differing amounts of detail in the resultant images (FiguresÂ€7.2 and 7.3). 7.2.1â•…Reflection Reflection of incident light occurs as a result of a portion of the total amount of light energy that bounces back from an illuminated surface and does not penetrate the surface. The complex properties of skin as well as the wavelength of incident light determine the amount of reflection. Light that is not reflected penetrates into the skin and becomes absorbed as it diffuses. Measurements of penetration of light into skin are calculated using Beer’s law (FigureÂ€7.4).

Skin surface detail is best captured using ultraviolet (UV) light [3]. When UV light hits skin, neither reflection nor fluorescence can be seen with the unaided human eye. The fluorescent properties of light on skin are better captured using another technique: alternate light imaging (ALI), which is described later in this chapter. In surface skin disruption such as in a bite, the reflective UV photograph highlights the differences between normal and damaged tissue (FigureÂ€ 7.2, lower left and lower right). 7.2.2â•…Absorption A portion of the incident light energy penetrates below the epidermis, particularly the longer wavelengths of light. Within the dermis, light absorption occurs. The

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 7.3â•‡ Same bitemark as in Figure 7.2: color infrared digital image (upper left). Fujifilm IS-Pro, Nikon quartz UV 105 lens, ISO 200, f/25.4, 1/80 second, sRGB, #87 filter, synched flash; monochrome (IR) digital image desaturated in Photoshop (upper right); color ALI. Canon EOS 10D, 50-mm Canon lens, ISO 1600, F/3.5, 1/15 second, #15 Tiffen filter, 450-nm Spex CrimeScope ® light source (lower left); monochrome alternate light digital image desaturated in Photoshop (lower right).

BEER’S LAW Measures the exponential decay of intensity as light travels through a media.

% transmission Depth

I = Ioe–αx

I = intensity measured in watts/cm2 Io = intensity at the surface E = 1/2.71828 (essentially 1/3, an exponential constant) A = absorption coeﬃcient (how much light is absorbed per unit of media) X = distance into tissue the light travels

Figure 7.4â•‡ Explanation of Beer’s law.

Photography

physical elements in the dermis (neurovascular components, hair and sweat cells) and blood products associated with the bitemark injury are responsible for absorption. The longer the wavelength of light, the farther into the dermal layer it travels. If a bite has sufficient force to cause bleeding in the deeper skin layers, the properties of the long-wavelength infrared (IR) light can be used. Infrared light penetrates up to 3 mm below the surface of the skin [4] and is highly absorbed by blood products associated with bruising. While not visible to the unaided human eye, IR light can assist in visualizing when bleeding has occurred well below the skin surface (FigureÂ€7.3, upper left and upper right). 7.2.3â•…Fluorescence Light energy striking skin also creates an excitation at the molecular level. As the molecules return to a normal energy state, they leave behind a faintly visible glow known as fluorescence. This phenomenon lasts for ~100 ns (10–8 s) [5]. Alternate light imaging is required for the eye to see fluorescence. This technique also accentuates differences between the injured and uninjured tissue (FigureÂ€7.3, lower left and lower right). 7.2.4â•…Diffusion The final event that occurs as light contacts skin is called diffusion (also sometimes referred to as transmission). This event involves the scattering of light within tissue when skin is illuminated. Because light diffuses through skin, it is not recovered or seen in photographic images. 7.2.5â•…Summary In traditional color photography, visible light that strikes skin exhibits four phenomena: reflection, absorption, fluorescence, and diffusion. The combination of these phenomena characterizes what appears in the bitemark image. The dark areas associated to the bitemark represent absorption; the light areas indicate reflection. Although fluorescence occurs, it is not observed in the image without using special techniques with filters and monochromatic light. The diffusion of light within skin is not recoverable and therefore is not a useful component of bitemark photographic images. The set of photographs in FigureÂ€7.5 will supplement FiguresÂ€7.2 and 7.3 and help familiarize the reader with the different appearance of bitemarks when different photographic techniques are used. These images were all taken during the same photographic session. In some instances, even the best photographic efforts cannot improve the quality of a poor bitemark,

77

regardless of the wavelength of light used, as witnessed by the four photographs of the same bitemark on the arm of a homicide victim in FigureÂ€7.6. All photos were taken during the same session.

7.3â•…Conventional (Visible Light) Photography By far, the most common method of documenting bitemarks involves the use of conventional camera equipment manufactured for the visible light spectrum. Digital technology has virtually replaced film photography in forensic applications and is now routinely accepted by the courts. Both film-based and digital camera systems are optically designed to work within the visible light spectrum of electromagnetic radiation. Under normal conditions, creating a digital image is relatively simple, predictable, and affordable, and it has the added convenience of immediacy. The imaging potential of currently available digital cameras, lenses, flash units, and image capture devices is ever increasing. It is becoming easier to take very highquality images using different combinations of camera equipment. Bitemark documentation requires that the resultant images accurately depict the bitemark pattern on skin. This requirement precludes the use of simple consumer-class cameras and inferior-quality optical systems. However, it must be stated that if only a low-Â�quality camera is available, such as a disposable camera, the requirement of photographing the bitemark cannot be disregarded. This may be the only opportunity to record the trauma. The authors suggest using a digital single lens reflex (DSLR) camera with close-up (macro) capability and excellent optical resolution. Following these recommendations will allow the photographer the opportunity to capture many images in a short period of time and potentially increase the amount of evidence recovered.

7.4â•…Digital Photographic Systems The camera is only one of several components of the entire digital photographic system. It is suggested that one first decide what type of images are going to be gathered, how they will be stored, how large of a print will be made from the image file, and which software will be used to transfer and/or adjust the images. Numerous manufacturers of digital components provide complete systems with technical support. The authors suggest the buyer contact a knowledgeable vendor that can guide their selection.

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Figure 7.5 Color photograph of a bitemark on the shoulder on the day of the homicide. FujiPro S3 UV-IR camera, auto

setting, synched Nikon SB-140 flash, Nikon Nikkor UV 105 lens, Baader visible light band pass filter (upper left); black and white (upper right); UV photograph (lower left), FujiPro S3 UV-IR camera, ISO 100, f/5.6, Nikon SB140 synched flash at UV setting, Baader Venus UV band pass filter, 1/60 second; ALI photograph desaturated in Adobe Photoshop (lower right), FujiPro S3 UV-IR camera, ISO 400, f/22, RC forensics blue/UVLED at blue setting, 1/2 second, Kodak 15 gel yellow band pass filter.

7.4.1 Professional, Pro-sumer, and Consumer Cameras The decision about which level of sophistication one needs in a digital camera depends upon some fundamental ground rules that include price, features, and the quality of desired images. Digital cameras are very much like cars. There are high-priced stylish models, basic transportation models, and everything in between. Professional digital cameras used during commercial, entertainment, and sporting events are at the high end of the camera spectrum. Usually priced in thousands of dollars, they have highly sophisticated features designed for the professional photographer who knows how to use them. A professional-grade camera will perform virtually any task required for digital image creation. The pro-sumer class of camera is one that has many of the professional’s features but is midpriced in the several hundred to low thousands dollar range. This is the predominant class of cameras seen in most forensic investigations. The light-gathering capability and ISO

equivalence are usually slightly less than the professional models but adequate enough for most crime scene documentation. The optics and autofocusing capability are of slightly lower quality and the file size (megapixels) of acquired images is usually lower. Even with these limitations, a vast number of acceptable midpriced digital cameras are available for various photographic applications and venues. The basic 35-mm format digital camera (DSLR) with electronic throughthe-lens (TTL) capability is the ideal camera for most forensic photographic situations. The image framed in the viewfinder is the same as the captured image. Many reasonably priced high-quality digital cameras work with fixed or interchangeable lenses. There are also digital cameras with fixed “zoom” lenses that capture images in macro, portrait, and telephoto distances. The consumer-class camera is designed for the lessknowledgeable photographer who intends to use the camera for more casual photographic images such as family photos, vacations, etc. There are more models of this class of

Photography

79

Figure 7.6 Color photograph of poor-quality bitemark on an arm (upper left), Nikon N6000 camera, auto setting, Nikon

Nikkor UV105 lens, Nikon SB140 synched flash, Fuji color 100 ISO film; black-and-white photograph (upper right), Nikon N6000 camera, auto setting, Nikon Nikkor UV105 lens, Nikon SB140 synched flash, Kodak TMAX 100 ISO film; UV photograph (lower left), Nikon N6000 camera, f/5.6, 1/60 second, ISO 100 Nikon Nikkor UV105 lens, Nikon SB140 synched flash, Kodak Plus X 125 ISO film, Kodak Wratten 18A UV band pass filter; IR photograph (lower right), Nikon N6000 camera, ISO 50, f/22; 1/60 second, Nikon Nikkor UV105 lens, Nikon SB140 synched flash, Kodak high-speed infrared film, Kodak Wratten 18A UV band pass filter.

camera than the two previous classes combined due to high public demand and low retail cost. Most of the less expensive 35-mm format cameras (so-called “point and shoot”) are capable of taking good-quality photographs but have a non-TTL viewfinder. Many recent models circumvent the problem with a preview feature shown in an liquid crystal display (LCD) located on the back of the camera body. The lack of TTL may sometimes introduce a parallax problem when framing the image to photograph. This problem may not manifest itself until prints are in hand. Parallax problems and poor optical properties of plastic lenses are inherent to disposable cameras. The authors do not recommend this type of camera for bitemark documentation. However, it is not a bad idea to have a low-end digital camera available as a backup if everything else fails. An image acquired from a pocket camera is better than no image at all. 7.4.2 Lenses The camera lens transmits light through a series of ground and polished glass elements and focuses it onto

electronic sensors to create the image. As a general rule, the higher the quality of the lens, the more precise and sharp the image will be. Glass lenses work better than plastic ones. Compound multiple element lenses are best for highly detailed and sharply focused photographs. Lenses range in quality and cost; typically, the higher the cost is, the better the quality will be. If the camera uses interchangeable lenses, consider a lens that has both zoom capability and a calibrated macrosetting for closeup photographs. Utilizing a zoom lens permits the acquisition of subject orientation and close-up photographs with the same lens. Focal lengths may range anywhere from 1 in. to infinity. Additionally, they often have a special chemical (fluorite) coating that blocks all UV and IR light. The photographer will need to experiment with the lens to know its capabilities prior to case use. As a rule, digital cameras with fixed “zoom” lenses are better time-savers in forensic fieldwork than cameras that require several lenses to document crime scenes.

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7.4.3â•…Flash Accessories The light required to expose an image properly can be supplemented with the use of a flash. When properly connected to the camera body and synchronized, the flash unit will strobe simultaneously during exposure to add sufficient light to create the optimal image. For macrophotography, adjustable flash units or nonadjustable flashes with a guide number of 35–40 provide adequate light. Too much light leads to overexposure; too little light leads to underexposure. Since all cameras and flash units are not the same, the photographer should experiment with exposure settings and flash for the best results. Many commercially available DSLR cameras have built-in software-controlled flash units; others lack user controls, and still others are fully programmable. Automatic fill flash provides light when conditions require it. User override of the fill flash feature is frequently required in macrophotography. Other disadvantages of built-in flash units are their limited capacity for under- or overexposure and nondetachability. The ability to change both exposure setting and flash angle is a desirable property in photographing three-dimensional bitemarks. This specialized flash-driven technique is not available with a fixed flash (permanently attached camera-controlled flash) (FigureÂ€7.7, left). Using a detachable flash, the photographer has the ability not only to control the flash output manually, but also to move the flash position to angles other than perpendicular (FigureÂ€ 7.7, right). Too much light from a perpendicular angle may cause a “flash burnout” in which the reflection of direct light from the flash floods the injury and no detail is recorded in the image. This becomes more of a problem when the flash is fixed on the camera by the manufacturer and metered by the camera. The type and intensity of the light emitted by the flash as well as the direction from which the light strikes the bitemark will have a definite impact on the appearance

of the injury. It is recommended that a detachable flash unit be used in bitemark photography to provide the photographer maximum versatility. Varying the angle of incident light can make the same bitemark appear totally different (FigureÂ€7.8). 7.4.4â•…Digital Video Cameras Real-time digital imaging began with the invention of slaved video cameras connected to a computer. HistoriÂ� cally, these cameras were large, boxy, heavy equipment with very poor optical resolution. Although they were quite ungainly, much research has been done in the area of reflective UV photography with mounted video cams (Hamamatsu Photonics, K. K., Hamamatsu City, Japan). In early tests, the images were recorded at a lowÂ�resolution, low frame-per-second rate and visualized on the computer monitor. Thankfully, technological advances in digital camcorders have developed at an equal pace with digital still cameras. Today’s manufacturers often incorporate a tiny video camera lens embedded into the frame of the laptop computer or a cellular phone that will capture video files with excellent resolution and write it to memory at a surprisingly fast rate. Many 35-mm pro-sumer DSLR digital cameras also have a camcorder or video feature. From a forensic standpoint, video photography is valuable in numerous applications, including areas such as bitemark injury orientation, documentation, and crime scene and accident reconstruction.

7.5â•…Forensic Photographic Protocol To incorporate aspects of the electromagnetic spectrum and the associated photographic techniques used to capture the images, it is necessary to develop a forensic photographic protocol, sometimes referred to as standard

Figure 7.7â•‡ Camera-based flash system (left). Detachable flash system (right).

Photography

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Figure 7.8 Taken with a light source at perpendicular angle to the bitemark (left); note incisal edge detail. With a lowangle light source (right); note pinched tissue at tooth embrasures.

technique. A typical standard technique for forensic photography would include wide-view color images of the body that act to orient and document the precise locations of the injuries, followed by macro (close-up) images, in color and black and white, taken with and without a photographic scale of all injuries. After capturing the visible light images, special photographic technique images, including UV, IR, and ALI, are taken. If the digital camera has a video setting, digital video can be incorporated in the orientation to close-up bitemark evidence preservation. This sequence of image capture is followed for each injury photographed. The standard technique requires that all recorded images be reviewed to verify correct camera position, clarity, focus, lighting, and any other detail involved in capturing sharply focused and detailed images. Any images deemed to be below an acceptable quality are retaken. Finally, after it is determined that all images are of acceptable quality, the number of images taken for each photographic technique (visible-light color, black and white, UV, IR, ALI) is individually recorded on the photographer’s case management log as a historical record of the entire photographic case. The latter is also referred to as logging, a standard operating procedure (SOP) discussed in an upcoming chapter. Photography is the most common of the noninvasive techniques and may be the only opportunity for the investigator to document the injury. The use of the photographic scale is critical because it provides a visible reference showing the dimensional size of the bitemark. Without the scale, life-size enlargements cannot be accurately reproduced. Great care should be taken to avoid placing the scale so that is obstructs any part of the injury. It is for that precise reason that the standard

technique requires taking images with and without a scale, ensuring that the scale is not used to obstruct any part of the injury. 7.5.1 Photographic Scales Numerous types of photographic scales are used for forensic photography. The ABFO no. 2 scale designed by Hyzer and Krauss is strongly recommended for bitemark photography. This multifunctional scale helps with both dimensional accuracy and grayscale color references. The right-angled shape provides a reference for measuring (correcting) photographic distortion of the scale in two planes. It is important to understand that applying digital correction of the ABFO no. 2 scale in two planes may further distort the bitemark image, so great care must be exercised before rendering a digital correction of perceived photographic distortion in an image. If an ABFO no. 2 scale is unavailable, reference objects such as rulers, coins, or paper clips can also be used. Any object used in the images as a size reference, other than an ABFO no. 2 scale, should be kept as evidence and maintained in the case’s chain of evidence.

7.6 Visible Spectrum Imaging The most common images taken in bitemark cases are visible-light color and black and white. These images accurately capture the details of the bitemark as it was seen with the unaided eye. The resultant image appears exactly the same as it did in real life and will be the single best source of preserving the bitemark

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historically. Evidentiary preservation using photographs is readily accepted as an accurate and reliable depiction of the details of the bitemark in the legal system. As was previously discussed, most readily available medium- to high-quality off-the-shelf digital cameras can easily provide sufficient image quality to be used routinely in color digital bitemark photography. The best digital cameras, which are more expensive, allow many of the more desirable features of interchangeable lenses, removable independent flash units, and more precise manual camera settings and will render better image variety and quality. However, for the average bitemark photographer, the increased costs may not be justified if proper image capture techniques are used. Following the standard technique for image acquisition, color orientation images are taken of the bitemarks followed by macroimages taken in color and black and white (if the digital camera offers a black-and-white image capture setting), with and without the photographic scale in place. Again, the scale should not cover any part of the bitemark injury. It is not usually necessary to use a tripod when visible light images are captured, assuming the environment where the images are created has sufficient ambient light available to meet the requirements of the camera. It may seem redundant to require taking both color and black-and-white visible-light images. But there are definite differences in how a bitemark appears when viewed in color versus black and white. Because the retina has more rods (which differentiate black and white) than cones (which differentiate color), removing the color can at times enhance minute details within the bitemark. The color images create a rendering of the bitemark in its most graphic appearance. Humans see in vivid color, so creating a color image of the bitemark preserves the injury as it was seen. However, the minute details of the bitemark are best seen in black and white. A native black-and-white image created by the camera’s microchip is finest since it uses the camera’s programming algorithm to process the image. If the digital camera does not allow native black-and-white image creation, color images can be desaturated by editing software such as Adobe® Photoshop®. It is important to realize that, although it is acceptable to create a monochromatic black-and-white image from a color image, this is a manipulation of the color image data file. Therefore, it is best to capture the image with a camera setting for black and white. 7.6.1 Visible Imaging Technique Although it is not recommended, many bitemark cases may have traditional visible-light photography only.

Realistically, even forensic photographers may not have access to or expertise in specialized techniques such as ALI or nonvisible light. This places an additional burden on the photographer and technique to do it right the first time. There is no maximum number of images that should be created. One should take as many as is necessary and as circumstances dictate for that particular case. Evidence collection in the living and deceased using visible-light digital photography begins with orientation photographs that demonstrate the location of the injury or injuries. Typically, only color images are created for the orientation views of the bitemarks. Sequential images of the bitemark, with and without the scale, are followed by macrophotography, which requires the use of a macro lens and/or a macrosetting on the digital camera with a synchronized detachable flash. If the bitemark has threedimensional characteristics, additional macroimages are produced with a flash detached from the camera body and positioned at various angles to highlight detail. Using a detached flash unit may require that the camera be mounted on a tripod. All images should be reviewed when they are created and retaken if they are unacceptable. It might be important to execute serial images at different intervals to observe changes in the bitemarks, whether the bitemark recipient is alive or dead. Proper lens, scale, and bitemark orientation are imperative to capture bitemark images accurately. The injury, the lens, and the scale all need to be parallel to one another, according to Krauss [6]. Accomplishing each of these requirements ensures accurate capture of size and orientation of the bitemark. Lack of parallelism will create photographic distortion and complicate bitemark assessment. There are digital techniques for the correction of distortion, but proper parallel orientation of scale, lens, and bitemark minimizes this concern.

7.7 Digital Image Acquisition The explosion in digital imaging has led to significant enhancements in image capture and quality and eliminates chemical processing. Manufacturers continue to refine the camera with improved and more sensitive photodiodes, more precise sensors with a greater number of pixels, and better processing algorithms, thus providing an increase in the density of the digital image. Depending upon which of these characteristics the manufacturer includes in the camera, the cost and utility of these features can impact the overall quality of the bitemark images. It is suggested that the photographer spend time learning the current state of digital imaging, the associated costs of the latest enhancements and features, and

Photography

the versatility of a given camera system for such things as macrophotography, low-light image handling, the inclusion of detachable flash units, interchangeable lenses, the properties of the image capture sensors, image creation and quality, the density of the pixels after image capture, and the properties of how the lens, flash, and image capture sensor work to create the image. Usually, as price increases, so do the more desirable camera features. 7.7.1â•…Image Capture Sensors The two main digital image sensors used today are the charged coupled device (CCD) and complementary metal oxide semiconductor (CMOS) (FigureÂ€7.9). These electronic components were invented in the late 1960s and early 1970s. CCD sensors are made of silicon and are quite expensive to produce. Their size and quality have a direct effect on the price of the camera. These devices are located behind the lens, where the light energy is captured, processed, and transferred to the image storage media in the camera. Image capture devices are composed of arrays of tiny photodiodes that record light energy and then send it to a voltage converter as an analog signal. The software drives the image sensor’s algorithm and thereby converts the electronic data to a digital image. How that process occurs is vastly different in CCD sensors and CMOS sensors. CCD sensors capture the light with the filtered photodiodes and process it “into electronic signals at output nodes where … it is converted to voltage, buffered and sent off-chip as an analog signal. All of the pixels can be devoted to light capture and the output’s uniformity (a key factor in image quality) is high” [7]. Because all the energy of the photodiodes on the CCD chip is dedicated to image capture, CCD image quality is more uniform

Figure 7.9â•‡ Capture elements. (Courtesy of Kodak.)

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(better) than CMOS. One trade-off is that CCD image processing takes more energy to create the image than does CMOS; this slows the image capture, in images per second, when compared to CMOS. This difference in burst rate can be a problem when multiple images are made in a continuous image capture mode. Some modified cameras use three separate CCDs— one each for red, blue, and green light—to capture the light energy that composes the image. “Light coming into the camera lens is split by a trichroic prism assembly, which directs the appropriate wavelength ranges of light to their respective CCDs” [8]. Because these cameras use a separate CCD for each of the red, blue, and green lights, there is no Bayer filter, and they achieve much better precision than single CCD cameras [8]. These cameras are referred to as three-CCD or 3CCD cameras and are more expensive than single-CCD cameras. CMOS sensors capture light in the same manner as CCD sensors but with one major difference. Each pixel on the CMOS chip “has its own charge-to-voltage conversion, and the sensor often also includes amplifiers, noise correction, and digitization circuits, so that the chip outputs digital bits. … With each pixel doing its own conversion, uniformity is lower” when all the pixels are assembled to create the image. However, when compared to CCD images, CMOS image quality is not as good. Generally, CMOS-based cameras use less energy and are less expensive than comparable CCD cameras. The image quality difference means that most camera manufacturers make CCD-based cameras, although the CMOS cameras are closing the gap. 7.7.2â•…Pixels and Color Image capture sensors in digital cameras are the equivalent to old photographic film, but that is where the comparison to film ends. Digital imaging has greater latitude in image creation, virtually no wasted time waiting for film processing, no cost, and immediate image viewing. The silver halide emulsions on photographic film captured the light energy after exposure. Then the film had to be rolled back into the canister, processed, and the subsequent printed images created before the results could be seen. Problems anywhere along this process required another photographic shoot, loss of time, and no guarantee of better results. In contrast with photographic film, digital capture elements (sensors) are produced in varying sizes. The size of the sensor dictates the cost of the camera, color accuracy, speed (ISO equivalence), light-gathering capability, zoom factor of the lens, and the magnification of the image. Sensors have microfilters that interpolate a monochrome image (256 levels of gray) into an accurate

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition Conventional Red Green Blue “Bayer Pattern” Sensor Array

New Kodak High Sensitivity Sensor Array with Panchromatic “Clear” Sensors in the grid.

Figure 7.10â•‡ Typical array of RGB pixels (left). (Courtesy of

Linear Systems Inc.) Super CCD (right). (Courtesy of Kodak.)

color image. These microfilters make up the basic components in a sensor and are referred to as “pixels.” Digital images are created using tiny building blocks of arranged and color-filtered photodiodes (pixels). In its simplest form, think of a pixel as a grain of emulsion on a strip of film. Pixels can interpolate the color several ways, depending on the manufacturing process. The two most common are red–green–blue (RGB) and cyan–yellow–magenta (CYM). Still others capture YC (chrominance and luminance) values indirectly from the sensor. A typical RGB sensor (FigureÂ€7.10, left) has several thousand clusters of four-element pixels per each color cell. The more pixels per image, the greater the versatility of the image to be enlarged or otherwise enhanced without losing critical image detail. In image sensors, the light energy is captured by the photodiodes through a color filter array called a Bayer filter. This filter was invented by Bryce E. Bayer of Eastman Kodak and is arranged so that each square grid of photodiodes (pixels) is composed of two green, one red, and one blue filter elements. The predominant light energy detected by each square grid (red, green, or blue) is passed along the image creation processing pathway that, when combined with all the other pixels’ dominant color detection and algorithmic interpolation, creates the image. Bayer used twice as many green elements as red or blue to mimic the human eye’s greater resolving power with green light [9]. Typical Bayer filter pixels only capture about one-third of the color information for each pixel, with the other two-thirds of the color interpolated by the camera’s image processing algorithm. Recent advancements by Kodak and others in the Bayer filter model include the addition of white or transparent filters with the green, red, and blue filters that change the basic Bayer filter of a square-gridded four-element filter to larger six- or more gridded filters

(FigureÂ€ 7.10, right). These modified filters increase the sensitivity of the image sensor by creating a sensor sensitive to all wavelengths of light (white light) and collect a larger amount of the light striking the sensor [9]. There is an inherent problem with this type of filtering system, particularly when the frequency of information is greater than the frequency of the filter groups, leading to an effect called “aliasing.” Aliasing can appear as a white area in a particularly detailed area of the image, surrounded by red-, green-, and blue-Â�colored pixels. Two methods for correcting aliasing include optical correction, usually by using quartz filters on the CCD, and software correction. The use of the quartz filter can directly and significantly affect the cost of the imaging system. 7.7.3â•…Aspect Ratio Most still cameras create images with aspect ratios (width by height) of 4:3, 3:2, or, more recently, even 16:9, which previously had been available only on high-end professional cameras. Printing enlarged images will become sized in multiples of the same aspect ratio as a 3:2 sensor: 6 × 4, 12 × 8, 24 × 16, etc. This feature can become problematic if a printed presentation is going to be formatted in traditional film dimensions. For example, a typical film enlargement can be printed as 8 × 10 in. without peripheral loss. A digital camera will create a file whose aspect ratio prefers enlargement to 8 × 12-in. size, but it may get printed as 8 × 10 in. during commercial enlargement. Hopefully, any crucial information contained in the image is not located at the edge that will be cropped during the enlargement and printing process. 7.7.4â•…Resolution and Compression Digital cameras are able to save files (images) in several formats. Some images are saved with compression, a method that squeezes the data into a smaller file. Resolution represents the quality of an image printed at a specific size. Both resolution and compression are important components of the image and will determine to what size it can be enlarged. It is possible to determine from the size of the print what file size and resolution are needed for the saved image by using the mathematical equation: height (in.) × width (in.) × pixels/inch × 1,000 file size (megabytes). For example, at 300 pixels per inch, an 8 in. × 10 in. × 300 pixels/inch image yields a file of 24,000 bytes or 24 megabytes (MB). One may also derive the file size by the actual pixels. This is usually a ratio of 1:3. For example, an RGB.tif file with no compression and a raw image of 1.2 million pixels will result in a 3.6-MB file. These terms must be

Photography

understood before an intelligent choice can be made on fulfilling the photographer’s needs if the digital image needs to be printed. 7.7.5â•…ISO Equivalence The ISO setting on a digital camera is nothing more than an emulation of film properties. Digital cameras have an advantage in that some can shoot images at incredibly high ISO equivalence settings. For example, a digital camera that has the capacity to capture an image at 6400 ISO can be set to shoot one stop faster than film rated at the same ISO, thereby increasing the digital ISO to 12,800. Moreover, some digital cameras have the capability to pull or push the images up to two additional full stops, resulting in a virtual ISO of 50,000. These images can be either monochrome or color. The greater the ISO is, the more “dark current noise” is introduced into the image (FigureÂ€7.11). This is equivalent to an increased graininess associated with high-ISO-rated traditional film. Some cameras can eliminate dark current noise by the application of a filter inside the camera. Other cameras eliminate the noise by applying a filter inside the software. Even more sophisticated, some cameras eliminate the noise by acquiring two separate images during the exposure (one with the shutter closed) [10]. Employing the application of a noise subtraction algorithm, the software eliminates the dark current noise. As with film-based photography, the higher the ISO setting is, the less light it will take to capture the image. Conversely, the lower the ISO setting is, the more

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light will be required to capture the image accurately. It will take some experimentation with any given digital camera to fine-tune the ISO setting for the amount of ambient light available for image capture. With digital cameras, correcting for under- or overexposure is simple: Change the camera setting and immediately retake the photo. 7.7.6â•…Lens Magnification If the sensor size is physically smaller than the actual film size for which the camera body was designed (i.e., traditional 35-mm-film-based cameras), this decreased size will magnify the image from the lens (FigureÂ€7.12). The 35-mm camera frame is 36 mm × 24 mm. Typical digital camera sensors measÂ�ure 4.8 mm × 3.6 mm (small sensor) to 6.4 mm × 4.8 mm (medium sensor) to 8.8 mm × 6.6 mm (larger sensor), yielding equivalent image capture areas from approximately 8:1 for the small sensor to 4:1 for the large sensor. The chip set in the sensor will interpolate the captured image to yield the equivalent 35-mm base image size. Magnification in sensors with a given lens is typically a factor of 1.2:1 or 1.7:1. To understand the effect of magnification on image, a 50-mm lens gives a magnification 1.5:1. The image equivalent will be of a 75-mm lens. Similarly, a 100-mm lens will give an equivalent digital image of a 150-mm lens. This presents an advantage during long-range surveillance and close-up photography since there is no loss of light in magnification.

Figure 7.11â•‡ Increasing ISO increases current noise. (Courtesy of Kodak.)

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 7.12 Actual sensor size (left). Effect of magnification by sensors (right). (Courtesy of Linear Systems Inc.)

7.7.7 Storage Devices The initial digital image storage occurs at the camera level or, via Bluetooth or other wireless technologies, directly from the camera to a connected computer. From there, the images can be viewed and either stored or deleted. At the camera level, removable memory storage cards will record the images as they are created. Most digital cameras have small, built-in LCD screens so that the images can be immediately viewed for acceptability. Typical intracamera body storage cards range from larger-sized CF removable storage cards to the more popular smaller SD cards to the micro-SD cards and range in storage size from 256 k to more than 10 gigabytes. Often, the photographer will carry extra removable storage cards that can easily be exchanged—a full card for a fresh, blank, formatted card—making it possible to collect a nearly infinite number of images for only the cost of the memory cards. Once the images have been uploaded or imported into the computer, storage, authentication, and viewing of the images can occur. At this point, depending on the intended use of the images, storage can go in several different directions, including long-term physical storage. Increasingly, larger digital storage media have accompanied the move to digital photography. A collection of several hundred 10-megapixel images can easily reach multiple gigabyte quantities for a given case. For this reason, there has been significant improvement in storing digital image files. Whereas in the past, burning images to a CD or DVD was convenient, today’s larger image sizes have rendered CD and DVD storage obsolete. Removable and portable USB drives of up to 64 gigabytes, external hard drives with 500 gig capacity, or storage to multiterabyte hard drives is now used for storing digital images. These devices can easily be backed up for protection and security purposes. In addition, their portability makes them very user friendly, not only for file storage but also for moving them to and from authorized users.

The future of digital image storage will likely rest on the use of additional secure online storage sites, such as those currently offered by proprietors such as Google® or Dell®, potentially allowing access to the images from anywhere in the world where an authorized user would have Internet access. For a fee, these secure sites will allow significantly large-volume storage that protects against the catastrophic loss of images in a hardware crash or malware virus contamination. Having both local and online secure storage provides the best of both worlds. For jurisdictions completely immersed in the digital imaging world, local area networks (LANs), synched with huge data servers and hardware storage through such systems as RAID, arrayed multiple hard drives tiered servers to huge multiterabyte (or more) “data farms,” will be used for image collection, storage, and preservation. These storage technologies are supported by redundant, frequent data backup to protect against the loss of the digital images. 7.7.8 Saving Digital Images A RAW file is an image saved directly from the camera’s imaging sensor and contains the most information of all file types; it is the largest of all files sizes for digital images. Usually, it is a secure file format that prohibits modification in imaging software applications. The RAW file also offers the ability of postexposure compensation and color correction, usually using an image editing/ enhancement digital software program such as Adobe Photoshop. A JPEG file is one that has been compressed from the RAW data into a smaller size for storage maximization and saved with a JPG file extension. JPG files are not secure and the user cannot change the values for exposure or color from the RAW data via image editing. Most quality digital still cameras produce either a RAW or JPG file; some produce both files simultaneously. The secure file format is a source for debate among forensic scientists, the legal community, and investigative

Photography

agencies alike. Although it is a “loss-less compression” type of file, a secure file is one-directional and can be viewed, edited, and modified in a software program. When it is edited, it cannot be written back to a secure file format. If the software does save the file under the same name and extension, the image was not an original to begin with. Secure file formats contain more information than any other file type. The information can include time of day, date, serial number of the camera, exposure number, and camera settings for each exposure. Working in a secure file format minimizes chain of custody issues because the authenticity of the image is provable. The most advantageous feature of a secure file format is that it becomes insurance against challenges of authenticity— an issue that could be raised in judicial proceedings. The only major drawback is the large file sizes. In some instances, it is not possible to create images in a secure RAW format. Under circumstances when secure images are not created, it can become necessary to encrypt the images digitally with information that can authenticate the file and associated information. There are several ways the images can be digitally encrypted; the easiest is the incorporation of a digital watermark. There are many ways to add digital watermarks, which can become quite useful if the nonsecurely formatted image should need to be verified as the pristine original image in chain of custody issues or in an associated legal proceeding. The question of when to use a secure file format is based on a number of considerations. Who will be getting access to the files? Where are they? How are they handled, where, and when? To whom will they be distributed? Who has access to the originals? These questions are important when the exchange of files (evidence) will occur inside law enforcement agencies and forensic labs and among experts, lawyers, and/or the courts. The same problems are encountered if the defense produces digital information in judicial proceedings. 7.7.9â•…Digital Scanners One way of converting analog images to digital data is by scanner. There are optical scanners that are designed specifically for reading film, slides, printed material, radiographs, or all of the above. In the typical flatbed scanner, the scanned material is placed on a glass platen. An optical sensor under the glass moves past the object and records it as a digital image. The sensor reads the object very much like a photocopier; however, in this case, instead of producing a print on paper, the software creates an image file that can be stored and managed. The optical sensor in the scanner works much like the sensor in a digital camera. Photodiodes with filters

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Figure 7.13â•‡ Casts of teeth digitized from a flatbed scanner.

capture the light created by the sensor of the scanner in either color or black-and-white image formats. The electronic image is then processed by the algorithms in the scanner’s chip set to create the digital image, converting the analog scan to a digital image. Several important scanner applications are relevant to bitemark investigation. Dental study models (casts) of suspects’ teeth can be imported as image files using a flatbed scanner (FigureÂ€7.13). Many odontologists use the image of scanned study models to create hollow volume and/or compound overlays for comparison to lifesize bitemark digital images or standard photographs. Images of a pattern injury can also be imported into an imaging software program such as Adobe Photoshop via scanned film, color print enlargement, or digital files. Once digitized, the image can be corrected for rotation, size, and photographic distortion [11]. The entire bitemark comparison and analysis can then be printed, demonstrated on computer, or projected via a laptop computer connected to an LCD projector.

7.8â•…Considerations for Digital Photography in Order of Importance While many considerations enter into digital image creation, the first is output. If the main intent is to print the images, how big the actual prints are going to be will

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determine file size, camera capabilities, and printer features. Larger prints of digital images require larger files with more resolution, which means more sophistication and advanced features in the camera. Are the images going to be subject to electronic distribution? If so, will it be through a network, server, or Internet e-mail? The larger the file size is, the more time is required for image transfer. Many Internet service providers limit the maximum file size they will accept. Some RAW image files may be too large to send via electronic distribution. RAW images will also require a plug-in software file that interpolates the digital information when importing it to an image software program. The second consideration is storage. Will the images be stored temporarily on a flash card, online, with a hard drive or RAID array, or near line via a network server or DVD jukebox (FigureÂ€7.14, left)? Flash card capacity has been steadily increasing and is well affordable, even in multigigabyte sizes. Will proprietary software such as DIMS [12] be required for image protection and nonoverwriting security? The file size and number of files to be stored will dictate the requirements for storage hardware. For personal usage, an external hard drive may be more than adequate; however, for long-term storage and security, one should consider an outside source where files are encrypted and uploaded to a professional storage and backup online service such as Carbonite®. A major metropolitan law enforcement agency may accumulate thousands of images daily. For this situation, a multiuser access drive with multiterabyte capacity may be necessary for storage (FigureÂ€7.14, right). The third consideration is retrieval. Who is going to maintain the software to download the images? Will

it be one person or several people on a LAN? Will that software be the same as the one that is used to find the image and work with it? How will the files be indexed, sorted, named, and saved? These questions are critical for multiuser input settings and must be answered before digital imagery is integrated into forensic applications. The fourth consideration is hardware requirements. The type of computer one uses for viewing and creating images and graphics must be adequate to fulfill the requirements of the job. The components should include a large amount of RAM (2–4 gigabytes), a hard drive with a minimum of 300 gigabytes, a fast processor, DVD reader/writer, and flashcard ports or Firewire® for faster downloading of images. Some additional considerations might include wireless connectivity, battery operation in case of power failure, and, last but not least, a contingency plan in case there is a general failure of digital imaging. The remote but possible failure of an application of digital imaging in a specific case reinforces the suggested redundancy by the authors of incorporating multiple digital cameras in one’s armamentaria as well as multiple, separate, secure image-storage devices and sites. The final consideration involves decisions to be made regarding the type and capabilities of the camera. Will a secure file format be necessary? How big a file will be needed and what size enlargement for working cases? What applications are available from the manufacturer for downloading and working with the images? How are images to be stored? Downloading and storing RAW images that are 30–50 MB in size on a home PC under these circumstances might create more problems than anticipated. Software selection is critical. What are the needs of the investigator? Eventually one can count on outgrowing

Figure 7.14â•‡ DVD/CD storage system (left). (Courtesy of Rimage.) Megaterabyte storage array (right). (Courtesy of

Plasmon.)

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Figure 7.15 Unretouched color image scanned from a slide (left). (Courtesy of Ontario Police Dept.) Enhanced Photoshop image (right).

Figure 7.16 Scanned from original color slide with no modifications (left). (Courtesy of Upland Police Dept.) Same photo after enhancement with LucisPro (right).

the next release of any imaging software package. Will it be upgradeable and appropriate to other applications? The worst-case scenario would be changing record management systems and/or operating systems. The user will need to know if the software is compatible with subsequent releases of operating systems such as Windows or Mac OS. Another important aspect of software consideration is the ability to manipulate or enhance the images rendered. As previously mentioned, Adobe Photoshop is one of many very powerful image management systems. This multipurpose imaging software suite has algorithmic options that offer total control over how the image is presented. Digital enhancement can frequently improve the appearance of bitemark images. Figure 7.15 (left) was scanned from a color slide and represents the maxillary arch on the sole of a child’s foot. Using Adobe Photoshop, the image was converted to gray scale and the bite isolated using the marquee tool. Enhancement of the bite pattern by altering levels of contrast and brightness resulted in Figure 7.15 (right). Another impressive enhancement software manager is LucisPro® [13]. This program was developed for a variety of medical and scientific applications and offers

a simple user-friendly system for bringing out details of bruises in bitemarks by means of two separate cursor algorithms. The latest version (6.0) has been adapted as a plug-in feature to Adobe Photoshop. Figure 7.16 (left) is a scanned color slide of the right calf of a female child-abuse victim. Figure 7.16 (right) is the same photo enhanced with LucisPro software with the large cursor set at 57 and the small cursor at 11. Note the improved visibility of the dental arches even though this bite was partially inflicted through the child’s clothing, as is evident by the elastic band imprint. In summary, before digital equipment is purchased, the authors suggest consulting with an experienced vendor that can integrate all components of a digital system and provide technical support when it is needed. Sooner or later that support will be needed—guaranteed! 7.8.1 Alternate Light Imaging Alternate light imaging, fluorescent photography, forensic light source photography, and narrow-band illumination are all synonymous for the process of recording a photographic image with the aid of a monochromatic light and a blocking filter. The technique of ALI is

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition LASER LINES STOKES SHIFT

PRIMARY LINES Ar CVL Ar Ar Ar

ABSORPTION

CVL Ar

EMISSION

400 nm

500 nm

600 nm

514.5 nm 510 nm 488 nm 496.5 nm 476.5 nm

(Line height proportional to % visible output)

700 nm

Figure 7.17â•‡ Remitted wavelength of light is of a different frequency from the illuminating source. (Courtesy of Linear

Systems Inc.)

founded upon a phenomenon entitled the “Stokes shift” after Professor G. G. Stokes [14], who discovered that the remitted wavelength of light is of a different frequency from the illuminating source (FigureÂ€ 7.17). Part of the energy of light at a particular frequency (measÂ�ured in nanometers) is absorbed by the subject matter it strikes. Once that energy, in the form of electrons, is absorbed, it creates a molecular excitation that seeks to return to its unexcited state. The return of the electrons to their resting state releases that energy as fluorescence. The remitted light (fluorescence) is of a higher frequency and lower intensity and cannot be seen in ambient conditions.

However, it can be observed by using filters that pass the remitted light and block the incident light. The equipment requirements for ALI are similar to those for other forms of macrophotography with the exception that one must employ a forensic light source for the incident light and a blocking filter over the lens to capture the fluorescent image. Tripod-mounted 35-mm camera and macrolenses are part of the standard armamentaria. FigureÂ€ 7.18 shows a schematic drawing of the ALI technique and how fluorescent images are captured photographically. There are many types of forensic light sources. These include lasers, tunable lights, and

Fluorescent Photography Fluorescing Subject

Forensic Light Source (Emits Narrow Band Wavlength)

# 15 yellow barrier filter blocks 450 nm light Transmits shifted light Camera

Figure 7.18â•‡ Fluorescent protocol.

FILM

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Figure 7.19â•‡ Blue ring flash (left). (Courtesy of RC Forensic.) Turnable forensic light source (right). (Courtesy of Rofin

Polilight®.)

personal-sized light-emitting diodes (LEDs). FigureÂ€7.19 (left) is of an LED ring flash that screws onto the filter already attached to the lens. A tunable light source (FigureÂ€7.19, right) has several selectable internal filters for varying frequencies of light illumination. Plexiglas goggles are used for the observer to detect latent evidence and view enhanced fluorescent objects at differing frequencies. The color of source light and shade of goggles used depends on the subject matter being illuminated and photographed. Alternate light imaging is firmly anchored in numerous applications of forensic investigation. Crime scene analysts and forensic photographers learn to utilize the appropriate light wavelengths to illuminate blood spatter, illicit drugs, fibers, fingerprints, and body fluids including semen, vaginal secretions, and saliva [2]. Virtually any organic compound found in nature can be made to fluoresce. The peak level of excitation that a compound exhibits when illuminated depends on the wavelength of the illuminating light and the chemical components of the substance [15]. Early research on the bioluminescence of human skin detected a peak excitation at 430–450 nm [16,17]. This range of visible light is coincidentally very near the long UVA range, but it is actually in the deep blue color of the visible spectrum. Illuminating tissue with the ALI technique provides a distinctive advantage when bruises, pattern injuries, and bitemarks on skin are photographed. When the ALI technique is utilized, the net overall effect of obtaining the fluorescent image of a bitemark is to enhance the visibility of the injury [18]. The biochemical explanation of how this image enhancement occurs is revealed in the differences between normal and abnormal (injured) tissue substances. Certain organic components, such as collagen, keratin, and subcutaneous fat in the layers of the skin (dermis and epidermis), are bioluminescent and readily

transmit light [19]. Other components, such as bilirubin, hemoglobin, and melanin, absorb light. Uninjured epidermis, rich in keratin, is highly bioluminescent. Contrasting blood components of hemoglobin and melanin that have collected in the injured areas of the bitemark are seen as dark areas of contusion. This difference in light absorption due to blood products and high light remittance of uninjured tissue is what creates the enhanced appearance of the bitemark. FigureÂ€7.20 (upper left) is a postautopsy digital photograph, taken with visible lighting by strobe flash, of a bitemark on the right lateral thorax area of a female homicide victim. FigureÂ€7.20 (upper right) is a close-up of the same bitemark taken with 455-nm blue LED light and filtered with a Tiffen no. 15 yellow filter. Differences in the injured and uninjured tissue are more visible in the ALI photo. FigureÂ€ 7.20 (lower left) is a digital IR image of the same bitemark, while FigureÂ€ 7.20 (lower right) was created with digital UV. Alternate light imaging is most useful in situations when there is minimal visible bruise pattern information present on the surface of the tissue, but below the epidermis there is significant bruising. ISO equivalence and exposure factors vary depending upon the individual situation. Unlike UVA photography, ALI must be achieved in total darkness with the exception of the forensic light source. Any ambient light will interfere with the image capture, particularly when the higher ISO settings are used. 7.8.2â•…Digital ALI Technique for Bitemark Photography A photographer should routinely be able to capture an adequate digital image with a minimum setting of 200 ISO equivalence. Exposure times can vary depending on several factors that will be discussed here. At 200

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Figure 7.20 Digital color photo of bitemark (upper left), Canon EOS 10D, 50-mm Canon macrolens, ISO 100, f/4,

1/60 second, sRGB, syncronized flash; ALI digital photo (upper right), Canon EOS 10D, 50-mm macrolens, ISO 800, f/5.6, 1/8 second, sRGB, RC Forensic Super R-lite at 475 nm, #15 Tiffen filter; monochrome digital IR (lower left), Fujifilm FinePix S3Pro, Nikon quartz UV 105-mm lens, ISO 200, f/27, 1/60 second, synched flash, #87 filter; digital UV (lower right), Fujifilm FinePix S3Pro, Nikon quartz UV 105-mm lens, ISO 800, f/4.5, 1/90 second, Nikon SB 140 full flash with UV filter, Baader Venus U filter.

ISO and with an adequately powered light source, typical exposures range between 1/4 second and 2 seconds at f-stop settings of f/4 to f/5.6 aperture. The light source and camera ideally should be placed at distances of 12–18 in. from the subject. Before exposure, the camera should be mounted on a tripod with the camera’s back surface and the ABFO no. 2 scale positioned parallel to the injury. It is advisable to prepare the shot and focus prior to turning out the overhead lights. With the camera set in manual mode, the light meter readings are taken through the electronic TTL viewfinder with the no. 15 yellow filter mounted to the lens, while illuminating the subject with the tuned blue light source in an otherwise dark room. The forensic light source should be set at or near 450-nm monochromatic light. Liquid light guides and fiber optic cables coming from the light source may be mounted on a tripod or handheld. If a personal LED or ring light is used, it is typically already fixed to the camera lens. Exposures should be bracketed by increasing and decreasing shutter speed. Bracketing with f-stops tends to reduce focal depth of field. The photographer should attempt to capture images at the smallest f aperture to maintain best focal depth. With a little practice, one may discover that, with ALI, slightly underexposed images may contain more

information than normal or overexposed images. Most internal light meters are typically not designed for reading monochromatic light. The result is that the meter misreads the intensity of 450-nm illumination and adjusts by allowing more light than is necessary for an accurate exposure. This problem can be corrected by changing the aperture setting and/or the exposure time. Many variables affect exposure factor. A person with a dark complexion (more melanin) will require increased exposure times due to more absorption and less reflection of light. Forensic light units come with different output strengths and bulb wattages. The conveyance of light, whether it is through a fiber optic cable, liquid light guide, or LED, determines how much luminance is transferred from the source. Photographing living bite victims presents some interesting problems since motion must be limited with the long exposure times that are sometimes required. Consequently, higher ISO equivalences are chosen. Typically, 400–1600 ISO is needed for capturing bitemarks with ALI in the conscious living, and absolute darkness is required. Any ambient light results in image contamination. As a rule, photographers attempting fluorescent photography should become familiar with their camera equipment, its capabilities, and the appropriate exposure

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settings prior to actual casework. Pretesting equipment under controlled conditions is highly recommended. Case Presentation 7.1 A 34-year-old Hispanic male received multiple stab wounds during a gang-related homicide. A bitemark on the dorsum of the right hand was observed and photographed (see FigureÂ€7.21).

Case Presentation 7.2 A 3-year-old male Hispanic was brought to the emergency room with obvious signs of felony child abuse and multiple bitemarks. The child subsequently died; the cause of death was attributed to blunt force abdominal trauma. The images demonstrate one of the more distinctive bites sustained on the child’s abdomen (see FigureÂ€7.22).

Figure 7.21â•‡ Color bitemark photograph on right hand of a homicide victim taken postautopsy (upper left), Canon EOS

10D, 50-mm macrolens, ISO 100, f/4, 1/60 second, sRGB, synched flash; ALI (upper right), Canon EOS 10D, Canon 50-mm lens at f/5.6, 1/3 second at ISO 800, sRGB, RC Forensic Super R-lite at 475 nm, Tiffen #15 filter; color IR image (center left), Fujifilm FinePix IS-1, sRGB, #87 filter, f/5.6, 1/60 second, ISO 200, synched flash; monochrome IR image desaturated in Photoshop (center right); color UV image (lower left), FujiFilm FinePix S3-Pro, Nikon quartz UV 105 lens, sRGB, f/4, 1/90 second, ISO 800, Baader Venus U filter, Kodak SB 140 flash set to maximum output; monochrome UV image (lower right) desaturated in Photoshop.

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Figure 7.22 Bitemark on the right abdominal area (upper left), Nikon D80 62-mm lens at f/4.5, 1/60 second, ISO 100, ring flash; ALI (upper right), Canon EOS 10D, 50-mm Canon macrolens, f/3.3, 1/60 second, ISO 1600, #15 yellow filter, RC Forensic flex-arm ring light, 455 nm; IR digital color (lower left), Fujifilm FinePix IS-1, f/3.6, ISO 200, 1/80 second, #87 IR filter, synched flash; UV digital protocol (lower right), Fujifilm FinePix IS Pro, Nikon quartz UV 105-mm macrolens, color sRGB, f/4, 1/60 second, ISO 3200, Baader Venus U filter, Kodak SB 140 flash set to maximum output.

7.9 Nonvisible Light Photography: Infrared Technique Infrared light possesses special properties when directed on injured skin. It is possible to capture extravasation of blood beneath the skin surface, when it is present, using IR digital photography. While the patterns may not appear as sharply focused in IR as in visible or UV images, they can provide yet another source of digital imaging of bitemark documentation. Subdermal hemorrhage can occur when teeth or other objects crush tissues. The IR technique takes advantage of light absorption in areas of bruising that consequently appear black in the resultant image. Frequently, the individual groupings of blood patterns

recorded in the IR images may record the biter’s dental signature in a bitemark. The appearance of the IR photographs is different from those of UV, ALI, and visible light images. Because the focus point of IR images is up to 3 mm below the surface of the skin, the IR photographs often appear grainy and/or blurry as compared to those taken in other light media [4,20]. Failure of a bitemark to appear in an IR photograph may not be the result of poor technique. The more likely cause is the lack of bleeding below the skin surface [2]. In a living victim, IR photography is best utilized within the first 72 hours after the injury, with the subdermal healing beginning soon after the injury occurs. In a deceased victim, the subdermal changes also begin

Photography

to occur rapidly after death; however, depending on the environmental disposition of the body, it may be possible to capture IR images in an interval greater than 72 hours. Because the unaided human eye cannot see details of the bitemark captured in IR photography, it is recommended that this type of photography be utilized whenever possible in the collection of bitemark evidence [6]. 7.9.1â•…A rmamentarium for Digital Infrared Photography An IR photograph requires the use of special equipment, including a tripod, a 35-mm digital TTL SLR camera body capable of capturing infrared light, a lens that passes infrared light, an infrared light source, and an infrared band pass filter such as the no. 87 Kodak Wratten gel filter (FigureÂ€7.23, left) or the Baader IR glass band pass filter (FigureÂ€7.23, right). Some off-the-shelf 35-mm digital camera bodies have been found to work well for IR photography. While the published spectrum of light sensitivity for many of these unmodified cameras may not indicate it, they are capable of capturing IR light. Fuji® once manufactured several UV/IR full-spectrum 35-mm digital cameras, but it no longer does. At this time, there are no camera manufacturers making full-spectrum digital cameras. However, several after-market companies will take most of the medium to higher quality 35-mm digital cameras from the major manufacturers and convert them to a full-spectrum digital camera. There are many commercial lenses that pass IR light. However, the Nikon Nikkor UV105 lens has been the gold standard because it was specifically designed for passing both visible and nonvisible light. Unfortunately, as with the Fuji UV-IR camera, this lens is no longer

95

produced. Readily available commercial lenses are made with a fluorite coating on the lenses that acts as a filter and allows only visible light to pass. It may be possible that a given commercial lens, designed for only visible light photography, will pass amounts of IR light sufficient to create an image as long as the camera sensor can capture IR light. To fill the need for UV and IR, several manufacturers do make full-spectrum quartz lenses that work beautifully for IR photography. Often, an Internet search will list companies that offer these full-spectrum silicon-based lenses. Finally, an IR-emitting light source must be used to create IR photographic images. Some commercial flash units will emit IR light, as do tungsten lamps, quartzhalogen lamps, special LED infrared light sources, and special full-spectrum commercial flash units, such as the unfiltered model of the Quantum® flash. Once all of the necessary equipment for IR photography has been gathered, it is critical to experiment with the entire setup by taking practice IR digital images to learn the camera system’s proper settings and capabilities. Multiple trial images should be created with widely bracketed settings and then compared to identify both the best IR technique and optimal camera system settings. In this way, confident that the optimal IR technique will be achieved, the photographer will be ready to document a bitemark case. 7.9.2â•…Infrared Photography Technique IR photography normally requires the use of a tripod with the camera. Because the IR light penetrates below the surface of the skin, the camera is set to increase depth of field with an aperture of f/16 or f/22, and a bracketed exposure from 1/250 of a second to 1 second for each f-stop used. This will ensure that by slightly

Figure 7.23â•‡ Kodak Wratten No. 87 gel IR filter (left); Baader IR glass filter (right).

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underexposing the images (1/250 second) to slightly overexposing (1 second) them, the bitemark details present using IR light will be captured. The camera is positioned so that the front of the lens, film, scale, and bitemark are all in the same parallel plane. If a strobe flash is used, the camera’s ISO should be set to 25 or 100. Using the TTL viewing properties of the camera, the visible focus is established, the IR focus shift applied, and the IR band pass filter placed in front of the lens. To specify the exact wavelengths of light that are passed through the lens to the sensor, a band pass filter is required in IR photography. There are numerous inexpensive glass and gel IR filters. The Kodak Wratten no. 87 gel filter and the Baader IR glass band pass filters are specifically manufactured for passing only infrared light. The filter is placed tight against the lens after focusing. Using an IR-emitting light source, the image is created on the camera’s full-spectrum digital sensor and stored as a digital image. 7.9.3â•…Focus Shift Most commercially available lenses are manufactured to perform optimally within the visible spectrum of light, the range for which the focusing properties of the lens are calibrated. Additionally, the manufacturers place fluorite coatings on the lenses that specifically block transmission of nonvisible light. When photographing outside the visible light spectrum, it may be necessary to make small adjustments to the focus point to account for the nonvisible light [21]. The process of refocusing after establishing the visible focus is referred to as the “focus shift” (FigureÂ€7.24).

As previously mentioned, the focus for IR photography is up to 3 mm below the surface of the skin. Therefore, IR photography must account for the change in the visible focus by moving the lens slightly away from the object [4,20]. Many lenses have a small dot on the focus ring located to the right of the visible focus point that marks the infrared focus shift point. A focus shift is required for IR photographic images. In contrast to IR photography, UV photography highlights the surface details of the bitemark. Thus, the focus point in UV is closer to the front of the lens than the visible focus; if a focus shift is required, the lens is moved slightly toward the object being photographed. While others have championed the need for a focus shift of the same amount as infrared but in the opposite direction when taking UV photographs, the authors have found that no focus shift is necessary with UV photography when a quartz lens is used (FigureÂ€7.25, left). Practically speaking, once the photographer has the necessary equipment to begin UV and IR photography, it will take several photographic sessions of experimentation to determine the specific needs and techniques that will be required for optimal nonvisible light photography.

7.10â•…Reflective Ultraviolet Digital Photography If a bite inflicted to skin shows signs of damage on its surface (epidermis), the use of electromagnetic radiation in the UV range will often photographically depict the surface damage. For most organic materials, the rule of

Figure 7.24â•‡ IR focus mark on Nikon Nikkor UV 105 lens (left). The large black dot in the top picture represents the vis-

ible focus. The small dot to the right of the visible focus highlighted in the bottom photograph represents the IR focus. (Photograph courtesy of Nikon, Inc.) Close-up of IR focus shift point on Nikon Nikkor UV 105 lens (right).

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Figure 7.25â•‡ The quartz UV Nikkor 105 lens (left); Fuji IS-Pro UV/IR DSLR camera (right). (Courtesy of Fujifilm.)

thumb is that the shorter the wavelength of the incident light, the more the absorption will be and the shallower the depth of penetration. Disruption of the normal skin surface where the teeth touch during biting creates a physiological difference between the damaged areas and the undamaged adjacent skin. That part of the injury on the surface of the skin may have a potentially different UV appearance than in visible light. Under these conditions, the preferred photographic technique to capture surface disruptions employs the shorter-waved UV’s tendency to scatter off surface anomalies. This requires utilization of both UV light and the special armamentarium for taking UV photographs. The net effect is an observed enhancement in the appearance of the injury pattern [22]. Ultraviolet photography captures these subtle differences that cannot be seen with the unaided human eye. There is some controversy in the literature regarding the optimum timing for the use of UV photography. Suffice it to say that there is a wide variation in results from serial photos of the same injury over periods of 1–6 months. It is the authors’ observation that the best results have occurred between 7 and 9 days after trauma [23]. If one chooses to perform UV serial documentation over time, there is no need to retake orientation photographs since they should have been taken in the original series. Only close-up exposures with the scale in place should be taken during a subsequent UV series. The overall size (gross characteristics) and pattern (individualizing characteristics) of the injury are what is important.

7.10.1â•…Ultraviolet Digital Photography Armamentarium Ultraviolet digital photography requires the use of specialized photographic equipment and techniques. Levels of ultraviolet light range from the near ultraviolet to deep ultraviolet, and the armamentaria will depend upon which area of the UV band is to be captured. For this discussion, the basic requirements for capturing images in the 360- to 400-nm range will predominate. The equipment for digital UV photography starts with a pro-sumer class 35-mm DSLR camera with software and internal filtering system that have been converted to capture the nonvisible extremities of the light spectrum. The modification can be provided by the manufacturer, as in the Fuji UV/IR series (FigureÂ€7.25, right), or by conversion of a standard camera by a market vendor. Unfortunately, Fujifilm North America discontinued production of its UV/IR line of cameras in 2008. That fact should not discourage the novice photographer, since most basic 35-mm format digital cameras can be converted to “see” the UV range. One only has to seek a reputable and knowledgeable outsource vendor. The modification involves removal of the “hot mirror” filter in front of the electronic sensor and should be accomplished by a qualified technician. Modifying an older-model digital camera is more advisable than a brand new one since the modification would void any existing factory warranty. The next consideration is to acquire a lens that transmits UV light. Silicon-fused (quartz) lenses transmit

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75–80% of UV light and require no focal shift; however, they are scarce and very expensive. Nikon Corporation discontinued production of the UV105 quartz lens several years ago. To fill the demand, Universe Kogaku America [24] and Jenoptic Inc. [25] have developed a line of UV quartz lenses. Numerous less expensive, nonquartz, regular glass lenses are functional for UV imaging and transmit up to 50% of the UV. However, one must make certain that the glass surface is not fluorite coated and that no UV light will be transmitted. Consult the manufacturer’s specifications before purchasing the lens. A UV light source is also required. Direct sunlight, gas discharge lamps, YAG lasers, and ultraviolet-tuned LEDs are the most common sources of illumination. Although very inexpensive, sunlight does not produce the level of intensity required for capturing images indoors or in macrophotographic applications. Fortunately, several types of UV light sources are on the market, ranging from typical flash units modified to emit UV light to specially designed UV LED light sources. Recently, UV LEDs based on gallium nitride semiconductor alloys have become popular; they have several advantages over gas discharge lamps, especially in their spectral purity. For bitemark documentation, the preferred choice of illumination would be a very strong strobe flash, such as the Nikon SB 140, which was produced specifically for UV photography. Short of finding the unit, any programmable flash with a high guide value (50+), such as the Quantum® series flashes, should provide adequate light for digital UV imaging at high ISO equivalence (800–1600). In addition to the previous items, a UV-specific band pass filter must be in front of the lens in order to allow only UV light to strike the electronic sensor. The traditional Kodak Wratten 18A glass UV filter cannot be used in digital UV photography because of a small IR transmission spike that allows just enough IR radiation to leak through and contaminate the image. The digital camera’s sensor cannot differentiate between UV and IR radiation. Therefore, the 18A filter, which set the gold standard for film-based photography, is inappropriate for digital UV. The Baader® Venus U filter has become the accepted filter of choice for UV digital photography. It has a peak transmission at 360 nm and less than 0.1% red leak. 7.10.2â•…Digital Ultraviolet Protocol The UV/IR-capable digital camera should first be mounted on a tripod with the appropriate lens attached and proper filter holder positioned over the lens. The

camera mode function should be set to manual with a starting ISO equivalence of at least 400 and a shutter speed of 1/60 to 1/90 second. Exposures should be bracketed using multiple f-stops. If a programmable electronic flash unit is used, it should be set to maximum output. Camera distance to the bitemark may vary with the length of the lens. The injury and ABFO no. 2 scale should be included in the electronic viewfinder and focusing should be at the actual visible focus point if a quartz lens is used. If a glass lens is used, a slight adjustment in focus may be necessary. The ruler must be positioned adjacent to the injury and parallel to the back plane of the camera to minimize angular distortion. Once focus is established in ambient light, the Baader Venus U filter is positioned in front of the lens. Ultraviolet photography using a strobe-type flash can be accomplished in ambient room light illumination. If a gas tube or LED source is used, the room should be totally darkened except for the illuminating light source. Under these conditions, protective eyewear should also be worn by all present. Once the photographer acquires the essential equipment, predictable, reliable, and accurate UV photographs will be obtained through experimentation. It is imperative that the photographer be familiar with the UV technique before the advent of a real bitemark case. Failure to collect all the available evidence in the bitemark case could otherwise result. The recommendation that UV photography be used does not imply that it is compulsory in a bitemark case. However, it is the responsibility of the investigator to attempt to collect all available evidence when possible, and UV photography does represent one additional venue in evidence collection (FigureÂ€7.26).

7.11â•…Application of Photographic Techniques Other Than for Bitemarks The techniques described in this chapter can be applied in other areas of forensic investigation. Documentation of tattoos, scratches, or tool marks on decomposed tissue is an applicable venue for IR. Similarly, UV and IR techniques can be applied to tattoos, scratches, gunshot injuries, stab wounds, ligature restraints, hanging or suspension injuries, and many other types of patterned injuries. The ALI technique is applicable for examination of bruises associated with ongoing abuse or assaults or in instances where a history of aging injuries needs to be documented (see FiguresÂ€7.27 through 7.34).

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Figure 7.26 Child-abuse victim with bitemarks on the back; photo taken by child protective services 2 days after the attack (left); same bitemark injuries taken in RAW digital UV almost 2 months after the attack (upper right), Fuji Pro S3 UV-IR camera, ISO 100, f/5.6, 1/125 second, Nikon Nikkor UV105 lens, Nikon SB140 synched flash, Baader Venus UV band pass filter; desaturated and enhanced in Adobe Photoshop (lower right).

Figure 7.27 Color photograph of homicide victim with bullet hole in the left side of the neck (left); UV without significant change in the appearance wound compared to color (center); IR of the wound showing the entrance wound without apparent hemorrhage. The blood is still there but the camera focus is below the surface of the skin, making it seem to magically disappear.

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Figure 7.28 Color image of mummified back skin of homicide victim with tattoo; yellow box shows area of interest (left); IR photograph of same mummified skin with the details of the tattoo in the highlighted box.

Figure 7.29 IR photograph of neck ligature pattern in the skin of homicide victim (left); UV photograph of same ligature (right). Note the detail of the electric cord used for the strangulation.

Figure 7.30 Black-and-white photograph of knife puncture wound on homicide victim (left); IR (center) and UV of same injury.

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Figure 7.31 Child-abuse victim with ligature marks on neck (left); IR (center) and UV of same ligature marks.

Figure 7.32 Multiple series of tattoos on back of female (left); IR of same tattoos (right). (Courtesy of Miami Metro-Dade M.E. Imaging Bureau.)

Figure 7.33 Tattoo on face of homicide victim (left); IR of same tattoo (right).

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Figure 7.34â•‡ Black-and-white image of avulsed areola thought to be bitemark (left); UV of same avulsed tissue definitively showing the injury is not a bitemark (right).

References 1. Wright, F. D. 1998. Photography in bite mark and patterned injury documentation—Part I. Journal of Forensic Sciences 43 (4): 877–879. 2. Wright, F. D., and G. Golden. 1997. Forensic photography. In Forensic dentistry, ed. P. Stimson and C. Mertz, 102–106, 123, 132. Boca Raton, FL: CRC Press.. 3. Bachem, A., and C. I. Reed. 1930. The penetration of light through human skin. Publication of the University of Illinois, College of Medicine, Chicago. 4. Kodak infrared films. Kodak publication no. N-17, p. 4. 5. Ultraviolet and fluorescence photography. Kodak publication no. M-27. 6. Krauss, T. 1984. Photographic techniques of concern in metric bite mark analysis. Journal of Forensic Sciences 29 (2): 636. 7. CCD vs. CMOS: Dalsa.com; www.dalsa.com/markets/ CCD_vs_CMOS.aspx 8. Three CCD. http://en.wikipedia.org/wiki/3CCD (redirected from 3CCD). 9. Bayer filter. http://en.wikipedia.org/wiki/Bayer_filter 10. Canon U.S.A. Inc. 2003. EOS 10D digital camera brochure, p. 12. 11. Johansen, R., and C. M. Bowers. 2000. Digital analysis of bite mark evidence using Adobe Photoshop. Forensic Imaging Services, Santa Barbara, CA, pp. 17–44. 12. Digital information management solution. Linear Systems Corp., Rancho Cucamonga, CA. 13. LucisPro software, Image Content Technology LLC. PMB #203, 430 Franklin Village Drive, Franklin, MA 020384007, http://www.lucispro.com, http://www.lucisart.com

14. Stokes, G. G. 1853. On the change of refrangibility of light. Philosophical Transactions of the Royal Society of London 143:385–396. 15. Guilbault, G. 1973. Practical fluorescence. New York: Marcel Dekker. 16. Devore, D. 1974. Ultraviolet absorption and fluorescence phenomena associated with wound healing. Thesis for doctor of philosophy, University of London, Dept. of Oral Pathology. 17. Dawson, J. B. 1980. A theoretical and experimental study of light absorption and scattering by in vivo skin. Physics in Medicine and Biology 25 (4): 695. 18. Golden, G. 1994. Use of alternate light source illumination in bite mark photography. Journal of Forensic Sciences 39 (3): 1560–1567. 19. Regan, J. D., and J. A. Parrish. 1982. The science of photomedicine. In Optical properties of human skin. New York: Plenum Press. 20. Medical infrared photography. Kodak publication no. N-1, p. 26. 21. Nieuwenhuis, G. 1991. Lens focus shift required for reflected ultraviolet and infrared photography. Journal of Biological Photography 59 (1): 17–20. 22. Krauss, T. C., and S. C. Warlen. 1985. The forensic science use of reflective ultraviolet photography. Journal of Forensic Sciences 30 (1): 264–265. Henderson, J. W. 1993. Infrared photography revisited. Journal of Audiovisual Media in Medicine 16:161. 23. Wright, F. D. 1998. Photography in bite mark and patterned injury documentation—Part 2: A case study. Journal of Forensic Sciences 43 (4): 881–887. 24. http://www.ukaoptics.com 25. http://www.jenoptik-inc.com

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Practical Tips in Forensic Bitemark Photography Luc Gagnon Contents 8.1 Introduction 8.2 Infrared Photography 8.3 Ultraviolet Photography 8.4 Alternate Light Imaging Photography 8.5 Summary Reference

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8.1â•…Introduction Just a few years ago film was the product of choice for forensic photography; today, digital is the standard. This is particularly true for bitemarks since this type of evidence lends itself to color, infrared (IR), ultraviolet (UV), and alternate light imaging (ALI). What was a very long process with film now takes seconds with instant results. Good results in IR and UV photography can be obtained using a good single lens reflex (SLR) digital camera. But because in normal color photography IR and UV will greatly affect the results in a negative way, many cameras have built-in IR and UV filters. These filters greatly reduce the sensitivity of the charged coupled device (CCD) or complementary metal oxide semiconductor (CMOS) sensor, making it more difficult to capture IR and UV pictures. Longer exposure is required, as is adjustment for the focus shift. IR and UV filters are very opaque, and thus it is impossible to focus properly by looking through the lens. Mandatory manual adjustment of the focus is essential, followed by filter installation and picture taking. Finally, the use of bracketing for a clear image is critical in order to compensate for the focus shift. Experimenting with the Fuji IS PRO UV IR demonstrated that this particular camera is well suited to IR and UV photography. The filters are not installed by the manufacturer, thus allowing for those wavelengths to be captured easily by the internal CCD sensor. Besides being a lot more sensitive to IR and UV, the live view feature on this camera allows the user to see potential results before the picture is taken; this greatly reduces the time of exposure and solves the focus shift problem. The camera can also be used as a normal digital camera,

but needs a filter, such as the PECA 916 purchase option, to block IR and UV light. For the ALI technique, using a normal digital camera with the no. 15 yellow filter is suggested (see FiguresÂ€8.1 and 8.2). The use of a computer (preferably a laptop for convenience) and the software provided by the camera manufacturer such as the Nikon Capture—or, in the case of the Fuji IS PRO UV IR, the Hyper Utility 3—is recommended. This will allow the user to control the camera remotely on a tripod for immediate photographic results. It will be a lot easier to acquire a high-quality focused picture looking at the computer screen rather than looking through the camera viewer. Different types of light sources will provide IR and UV light. For example, most electronic flashes emit IR and UV light, but when the Fuji IS PRO UV IR is used in live view mode, it is very useful to use a steady-beam light source such as the Polilight Flare® from Rofin, which permits proper focus before picture capture (see FiguresÂ€8.3–8.5).

8.2â•…Infrared Photography Infrared photography enables one to capture lesions within deeper layers of skin. The principle is based on the fact that blood absorbs IR light, which appears darker than the surrounding tissue. Most CCD and CMOS sensors are a lot more sensitive to infrared light than to UV light, so short exposure and small aperture will normally give very good results. As with UV, the focus point could be off by a few millimeters due to a focus shift when a normal digital camera is used. This type of photography is very easy using the Fuji IS PRO UV IR; because it is very sensitive to IR light, this new

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Figure 8.1â•‡ This graphic illustrates the spectral transmission curve for the Kodak Wratten 18A filter. This ultraviolet filter allows some infrared penetration in the 700- to 800-nm range (http://msp.rmit.edu.au/Article_01/06.html). (Photo courtesy of MIT.)

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Figure 8.2â•‡ The spectral transmission curves for the Kodak Wratten series of infrared transmission filters. Notice that the 87C filter blocks light less than 800 nm (http://msp. rmit.edu.au/Article_03/02c.html). (Photo courtesy of MIT.)

camera facilitates infrared photography to the point that results can be seen before capturing the image. One of the light sources used is the new Polilight PL500 with infrared lighting. Three examples of the different filters available are the Hayo 72, the PECA 910, and Kodak’s Wratten 87C. The latter blocks all visible light other than infrared light. Depending on the distance and the infrared source used, it is easy to overexpose (especially with the Fuji IS PRO UV IR), so a very small aperture such as f/22 or even smaller is recommended. Good results have been obtained with f/27 at 1/125 second, depending largely on the strength and distance of the light source. Because each forensic case is different, a trial-and-error technique is suggested. Recommendations include:

• The use of a tripod (mandatory to facilitate manual focus) • The use of an ABFO no. 2 scale and its placement parallel to both the surface photographed and to the camera lens • Installation of a good infrared filter in front of the lens (the Kodak 87C blocks all visible light and lets in only infrared) As for UV, normally, IR photographs do not have to be taken in total darkness since the filter is very opaque to visible light. To make sure, simply take a picture with just the ambient light on, using a long exposure; if the photo is black, there should not be any contamination. The use of soft ambient light greatly facilitates picture taking. The focus shift for infrared will give a focus point away from the lens. One of the great advantages of IR photography is to show tattoos that would usually be hard to see under normal lighting due to burned or decomposed skin. For bitemark photography, infrared can be a useful tool, but UV and ALI often give better results [1] (see FiguresÂ€8.6–8.8).

8.3â•…Ultraviolet Photography In odontology, ultraviolet photography is particularly useful in order to accentuate the details on the undersurface of the damaged skin. UV photography has the advantage of being able to show details that would not normally be visible to the naked eye or in normal photography. Even though literature on the subject is quite

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Figure 8.3 UV and IR light source, the Polilight PL 500 (left), a laptop computer (center), and the Fuji IS PRO UV IR digital camera mounted on a tripod (right).

Figure 8.4 A laptop screen showing the Hyper Utility 3 software package included with the Fuji IS PRO UV IR camera shows results before and after picture taking, making it a lot easier to get a good picture every time.

meager, the best results were obtained after the bitemark is no longer visible. For UV photography, as for IR photography, many types of digital cameras could give decent results when using the proper light source and filter. However, it was

found that the Fuji IS PRO UVIR is well worth the investment if UV and IR photographs are taken on a regular basis. This particular camera is a lot more sensitive to those wavelengths than other digital cameras, and the live view is a great advantage over other cameras. Because

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Figure 8.5 Rofin Polilight Flare kit (left), Vector 7® UV light (center), and Ivona® UV light (right).

Figure 8.6 This infrared photograph shows the peripheral circulatory system of the arm.

Figure 8.7 A bitemark photographed in IR.

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Figure 8.8â•‡ Two pictures taken with the Fuji IS PRO UV IR camera with the Peca 916 filter (right) and without filter (left). The UV and IR are not being blocked.

of the latter factor, an appropriate focus is obtained every time, thus removing the guesswork from picture taking. However, even with this camera, the exposure time will be a lot longer than for infrared (see FiguresÂ€8.9–8.11). The technique of photographing a bitemark in UV is summarized as follows: 1. Install the camera Fuji PRO UV IR on the tripod. 2. Remove the UV filter on the lens if one is present. The filter is often used to protect the lens. 3. Install the UV 18A or a similar filter. 4. Set the camera to manual mode. The filter is so opaque to visible light that the TTL and the autofocus are useless. For example, using the Fuji IS PRO UV IR, good exposures have been obtained at 1 second, aperture f/10, with the beam of Polilight at approximately 30 cm from and 45° to the bitemark. On a live subject, it is important to keep the exposure as brief as possible since UV light has the potential to damage skin. The total exposure should not exceed 12 minutes per day and 4 minutes of continuous exposure with the Polilight PL500, making sure that the exposure is adjusted according to the UV source used and the manufacturer’s instruction. Depending on the UV source used, different results can be obtained. It is very important to know that the Kodak Wratten 18A filter also lets infrared light through (FiguresÂ€ 8.1 and 8.2). It is therefore possible to obtain photographs with more red depending upon infrared contamination, or more blue due to the UV source used. Ideally, the UV light source should emit no IR whatsoever. The source of UV light coming from LEDs seems to emit much less infrared. The Polilight Flare from Rofin is a good example and gives excellent results.

As for infrared, normally, UV photographs do not have to be taken in total darkness since the filter is very opaque to visible light. Simply take a picture in ambient light with a long exposure; if the photo is black, there should not be any contamination. The use of soft ambient light greatly facilitates picture taking. Remember that the Kodak Wratten 18A will let in a good portion of infrared light depending on how much the light source emits in the infrared wavelength. Ultraviolet light gives a focus shift of a few millimeters closer to the lens. Again, the use of the Fuji IS PRO UV IR live view mode eliminates this problem; otherwise, adjusting focus by looking at the photograph and using the bracketing technique will be time-consuming. Notice the difference in color in FigureÂ€ 8.11. All photographs were taken with the Fuji IS PRO UV IR and Kodak’s Wratten 18A filter with a variable UV light source. Some are contaminated to different degrees by the infrared light emitted, as seen by the different tints of red. The Polilight and the Polilight Flare seem to produce the best UV light source, emitting less IR and thus giving better detail.

8.4â•…Alternate Light Imaging Photography Alternate light imaging photography uses a yellow filter no. 15 and a 450-nm light source for photographing bitemarks. FigureÂ€ 8.12 illustrates the differences between no. 8, no. 12, and no. 15 filter photographs. Visually, filters no. 12 and no. 15 are indistinguishable and can easily be mixed up, although the photographs produced are perceptively different. The light source used in this figure was the Polilight PL500 from Rofin at 450 nm. A digital camera—preferably one sensitive to light (high ISO)—is ideal with an ABFO no. 2 scale. The technique

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Figure 8.9â•‡ Three photographs of a tattoo in color with ambient light (upper); IR with the Nikon D2X (center). Notice that it is out of focus due to the focus shift. The Fuji IS PRO UV IR was used for the bottom photograph. Both IR pictures were taken using the same Polilight and the Kodak Wratten 87C filter.

is particularly well suited for bitemark photography and other types of wounds or bruises that have a distinctive pattern. The ultimate goal is quite simply to improve the visibility and the contrast of the wound. The ALI method is remarkably effective when few visible details are present on the skin surface. (FigureÂ€8.13 highlights a color and an ALI yellow no. 15 filter bitemark photograph.) The Nikon D700, for example, has a very high light sensitivity (ISO) and gives a very good quality photograph at ISO 6400 with almost no dark current noise. This allows picture taking without a tripod—a very

useful tool when photographing bitemarks on a young, restless victim. A high-sensitivity camera will also allow for the use of smaller aperture settings in order to have a better depth of field. Very good results have been obtained with a shutter speed of 1/60 second at f/9. Do not rely on the internal light meter because the yellow filter and the 450-nm wavelength give a false reading. The technique is as follows: 1. Make sure that the anti-UV filter, often used to protect the lens, is removed and then install the

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Figure 8.10 Two pictures taken in UV; one with the Polilight (left) and the other with the Polilight Flare (right) using the same Fuji camera and Wratten 18A filter. This shows that results can differ when different light sources are used.

Figure 8.11 Four photos taken with the same camera and filter but with different UV light sources: Polilight Flare (upper left), Polilight PL500 (upper right), with the Nikon SB 800 flash (lower left) and a black light (lower right). Notice the different result, which is mainly due to infrared contamination.

no. 15 yellow filter. For this technique, the autofocus should work fine. 2. Protective glasses (yellow color) must be worn. Be aware that wearing these glasses may skew the vision, producing different results from what is anticipated. For this reason, one should monitor picture taking through the camera lens. 3. Use a no. 2 ABFO scale placed parallel to the bitemark and camera lens.

4. There should be no ambient light other than the Polilight set at 450 nm. The light source can be moved to different distances and directions to maximize bitemark photographic detail. Trial and error is in order. Looking through the camera lens while experimenting with light distance and position produces the best results. 5. Finally, it might be necessary to use a tripod, depending on the camera’s sensitivity to light.

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Figure 8.12 Three pictures using the ALI technique with three different filters: yellow no. 8 (left), no. 12 (center), and no. 15 (right). This shows the importance of having the proper filter for ALI—namely, the yellow no. 15.

Figure 8.13 Color (left) and ALI yellow no. 15 (right) filter bitemark photographs.

8.5 Summary The vast majority of SLR digital cameras can be used to take UV and IR pictures with good results. However, because using the Fuji IS PRO UV IR will greatly facilitate the process by removing quite a bit of the guesswork, it is highly recommended. It is important to remember that different light sources and filters can give different results, so it is recommended to experiment to obtain the best results.

Reference 1. Dorion, R. B. J. 2010. Bite mark profiling based upon color, UV, and ALI photographic interpretation. Proceedings of the 62nd annual meeting of the American Academy of Forensic Sciences, Feb. 22–27, 2010, Seattle, WA. Colorado Springs, CO: American Academy of Forensic Sciences.

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Image Processing and Analysis for Evidentiary Purposes William R. Oliver Contents 9.1 Introduction 9.2 Image Processing and Analysis 9.2.1 Image Processing 9.2.1.1 Definitions 9.2.1.2 Image Enhancement and Restoration 9.2.1.3 Substantive versus Demonstrative Image Processing 9.2.2 Image Analysis 9.2.3 Literature Review 9.3 Standards 9.4 The Digital Work Flow Pipeline 9.4.1 Images as Evidence 9.4.2 Image Acquisition and Archival 9.4.2.1 Storage Format 9.4.2.2 Primary, Original, and Working Images 9.4.2.3 Image Integrity and Archival 9.4.2.4 Format and Media Obsolescence 9.4.2.5 Image Authenticity 9.4.2.6 Image Retention 9.4.3 Image Enhancement Documentation 9.4.4 Report Preparation 9.5 Software Resources 9.5.1 Applicability 9.5.2 Single Application or Enterprise Solution 9.5.3 Validation and Algorithm Description 9.5.4 Graphical Interface and Ease of Use 9.5.5 Programming Requirements 9.5.6 Metaphor 9.5.7 Data Representation 9.5.8 Audit Trails 9.5.9 Third-Party Support 9.5.10 Open Source versus Proprietary References

9.1â•…Introduction Technological advances in the past few years have given us powerful, inexpensive tools for modifying images. What was traditionally the domain of specialized technical professionals is now available to the general practitioner. Image processing has become ubiquitous. It is so integrated into how one acquires and views imagery that it often cannot be separated from the act of taking pictures or looking at them. Modern digital cameras

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include multiple processing steps as part of the formation of a photograph. They allow the user to do tasks such as sharpening, image averaging, edge enhancement, color balancing, and even high dynamic range imaging within the camera. Modern displays offer similar functions. For instance, a common graphics card used in consumer laptop computers at the time of this writing allows the user to modify gamma, brightness, contrast, color balance, anti-aliasing, filtering, compositing effects, and resizing. Common consumer-level image processing

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software packages provide access to hundreds of algorithms in dizzying numbers of combinations. The evaluation of bitemark evidence has taken advantage of this, particularly in the areas of image enhancement, digital overlay production, and imagebased measÂ�ureÂ�ment. It is necessary, then, for those who use digital imaging to become conversant with the techniques employed. This chapter discusses considerations that may be important in image processing and analysis for bitemark interpretation from an evidentiary point of view. It is not meant to be a tutorial on image processing. That is a topic well beyond the scope of a single chapter; readers are encouraged to turn to any of the many good textbooks on the subject.

9.2â•…Image Processing and Analysis 9.2.1â•…Image Processing 9.2.1.1â•…Definitions Since the manipulation of imagery has become integral to its acquisition, storage, viewing, and analysis, it may be useful to think about what image processing is. One convenient model considers what kinds of data one is putting into a process and what kinds of data one is getting out of it. Basically, one can have either an image or some sort of descriptive data as input, and one can have an image or some sort of descriptive data as output, as shown in FigureÂ€9.1. In computer graphics, one provides a mathematical description of what one would like to see—a model of an object, a list of color and reflectance properties, a description of lighting, etc.—and the output is an image. In computer vision and image analysis, one uses imagery as input and attempts to derive some sort Input

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Figure 9.1â•‡ Categorizing image manipulation on the basis of input and output.

of description as an output (e.g. “there is an enemy tank behind a tree”). Generally, if a machine does the analysis, it is called “computer vision”; if analysis is done by a human, it is called “image analysis.” If one supplies a representation and receives a different representation, then one is performing any of a number of file-based tasks (such as format manipulation or compression) that generally fall under the classification of picture archiving and communications systems (PACS) in medical imaging. If one supplies an image and receives a modified image, then one is performing image processing [1]. Definitions of image processing vary a little between disciplines. In the world of forensic science in the United States, Canada, and Great Britain, definitions tend to be similar to those defined by the U.S. Federal Bureau of Investigation (FBI) Scientific Working Group on Imaging Technology (SWGIT). There, image processing is defined simply as “any activity that transforms an input image into an output image” [2]. The National Policing Improvement Agency of the United Kingdom states: “Processing images generally involves adjusting the technical properties of the image and modifying the actual content to improve or change some quality of the image” [3]. The Canadian Royal Mounted Police generally refers to the SWGIT guidelines for definitions, but expands on comments regarding image enhancement for analysis (vide infra). 9.2.1.2â•…I mage Enhancement and Restoration Forensic image processing is usually directed toward a few specific tasks. These tasks, in turn, can generally be categorized as image enhancement and image restoration. Image restoration is the process of reversing some degradation of an image due to acquisition technology or some environmental effect. The process often involves modeling the degradation process, creating a process that acts as its inverse, and then applying that inverse. A classic example in medical imaging is the restoration of conventional light microscopy images. In microscopy, the light traveling through the microscope from the light bulb is almost never uniform. Instead, it is brighter in the middle and darker at the edges of the field. There are almost always small bits of dust on the mirrors and lenses that cause dark spots. This is called “nonisotropic illumination.” Because the lenses are small and curved, different wavelengths of light are refracted differently, so red and blue portions of the image are no longer aligned at the edges. This is called “chromatic aberration.” In addition, because the lens is not a perfect sphere, light going through the edge of the lens will focus at a different spot than light that goes through the center. This is called “spherical aberration.” All of

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Anisotropic Illumination Correction

– = – Figure 9.2â•‡ Correcting for anisotropic illumination.

Figure 9.3â•‡ Before and after illumination correction.

these can be partially alleviated by better engineering and maintenance, but they will almost all still remain to some degree. Each of these can be modeled, however. For instance, an image is mathematically the multiplicative product of the illumination and the reflectance properties of the resulting image. Thus, one can normalize for uneven lighting simply by dividing the image by an image of the illumination (i.e., a picture taken without a microscope slide but with the lamp on). In contrast, light added by random currents in the sensor is additive, so it may be subtracted. To correct an image, then, one can subtract an image taken with the camera turned on but the light turned off (the “darkfield” image) and divide the image with the specimen by an image taken without the specimen (the “brightfield” image). The process is diagrammed in FiguresÂ€9.2 and 9.3. Similarly, one can take the blur out of out-of-focus images by modeling the blurring function and performing the inverse—either directly by a process called deconvolution or by using iterative methods. While there are methods of “blind” de-blurring that do not require a good model of the blurring function, the more efficient and better performing methods rely on a good mathematical model of how the blurring occurred. Image enhancement is the relative increase or decrease of specific features in an image to make it more

interpretable or, as defined by SWGIT, “any process intended to improve the visual appearance of an image or specific features within an image” [2]. Examples include the removal of distracting periodic patterns such as striations in concrete obscuring a shoe print or textile pattern in cloth obscuring a fingerprint, contrast enhancement to make faint features more obvious, and separation of color channels (FiguresÂ€9.4 and 9.5). The Canadian Royal Mounted Police guidelines for image enhancement for analysis say [4]: “Enhancements are intended to improve the overall appearance of an image or to extract hidden details within the image. Enhancements are not to hide anything from the courts and should only be performed on a copy of the original.” 9.2.1.3â•…Substantive versus Demonstrative Image Processing As described later in this chapter, there are a number of guidelines for the handling, documentation, and evaluation of image processing in forensic imaging. In large part, the degree to which these apply depends on how the image will be used. The primary distinction, particularly with regard to the courts in the United States and similar countries, is whether the processed image will be used simply to demonstrate findings derived elsewhere or if it is the basis for the interpretation. If one is going to enter an overlay of teeth on a bitemark into court, it

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Figure 9.4 Removal of background linear swept pattern in concrete to help view shoe print pattern.

Figure 9.5 Contrast enhancement of bitemark. Original image (left) and contrast-enhanced image (right).

matters whether the overlay is the basis for the conclusion that there is or is not a match or if it is to be used merely to show the jury what the investigator has determined using some other technique. Of course, one must know the rules of evidence for one’s particular jurisdiction. However, demonstrative imagery often must simply be stated by affirmation to be useful to demonstrate the point being made, be accurate in its representation of the point being made, be pertinent to the testimony, and not be prejudicial. While it is not described in the forensic odontology literature, in areas of investigation such as forensic pathology, image processing is often not the basis of the analysis but is instead used to create a collection or “space” of images that are processed using multiple methods and varying parameterizations [5]. These in turn are used to increase the likelihood that the observer will notice a feature pertinent to diagnosis. Recent studies in the cognitive science literature explain why this can be useful.

In studies of visual response to motion, researchers found that the brain creates potential futures out of remembered scenes and uses them to predict what one will see. This is modified when there is a significant discordance between what is predicted and what is actually viewed [6]. Interestingly, this kind of tactic was developed independently to speed up processing in computers, where it is called “speculative execution” [7]. This predictive process has advantages in terms of time and effort, but these findings suggest it may be a source of visual confirmation bias. The use of image processing to create a number of images with differing relative strengths of features may thus be used to force the visual cognitive system out of its expectations and allow the observer to notice features or relationships that he or she would otherwise have overlooked. However, since these newly observed features might be artifacts of the processing method, the analyst would be well advised to return to the original image and use it as the basis of his or her conclusions, except in certain

Image Processing and Analysis for Evidentiary Purposes

circumstances. The image processing is thus used to increase sensitivity, but any analysis based on the processed images alone would also have a much lower specificity [5]. Image processing, particularly contrast enhancement, has been studied extensively in the diagnostic radiology literature, where it has been shown to increase sensitivity, decrease specificity, and decrease time to diagnosis, depending on the task [8]. In mammograms, it increases the likelihood of detection of microcalcification, but not soft tissue mass detection [9]. It has also been used to evaluate drusen in retinal images [10]. As noted before, in certain circumstances the processed image is the basis for the conclusion. Measure ments of tooth position or area of injury may be derived from a processed image and form the basis for a statistical match. In these cases, it will usually be necessary to demonstrate the scientific basis for the conclusion, the error of the measurements, and the validity of the processing method. In the United States, the two primary tests for court admissibility are based on the U.S. Supreme Court decisions Frye v. United States and Daubert v. Merrill Dow [11,12]. The latter applies in federal court and many states and sets forth multiple criteria for determining the admissibility of scientific evidence. The former requires primarily that the method be generally accepted by the scientific community and it is still used in many states. In either case, any person using image processing in a substantive manner should have sufficient knowledge of the process to explain and defend its use. 9.2.2 Image Analysis While image processing focuses on modifying an image, image analysis focuses on extracting data and drawing conclusions from one. The SWGIT describes it as “the application of image science and domain expertise to interpret the content of an image and/or the image itself in legal matters. Major subdisciplines of forensic image analysis with law enforcement applications include: photogrammetry, photographic comparison, content analysis, and image authentication” [13]. Image processing may make it easier to see the edge of a bitemark. Determining the distance between teeth or the classification of marks is image analysis. Like medical diagnosis, it is a cognitive function that combines both art and science. In the United States, the criteria for admission of this kind of evidence was determined in Daubert jurisdictions by the Supreme Court in Kumho Tire Co. v. Carmichael, which decided that the courts had Daubert-like responsibilities in determining

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the admissibility of technical but nonscientific evidence [14]. In general, this has led to the evaluation of the certification, proficiency, and training of the examiner in addition to examination of the validity of the methods applied. Thus, image analysis requires knowledge of image science in order to understand and use imaging tools and demonstrate the scientific validity of the techniques. However, the analyst must also have knowledge of a domain of expertise in order to recognize and interpret important image features. A forensic odontologist may not be allowed to testify about conclusions based on a processed image if he or she cannot demonstrate an understanding of the processing method and how it affects the features he or she uses in analysis. An expert on image processing may not be allowed to testify about the meaning of the contents of a processed bitemark image if he or she cannot demonstrate competence in forensic odontology. In general, image-based analysis of bitemark evidence involves all of the tasks within the general area of image analysis, including photogrammetry, image comparison, and authentication. As defined by the American Society for Photogrammetry and Remote Sensing, photogrammetry in the general sense is “obtaining reliable information about physical objects and the environment through the processes of recording, measuring, and interpreting photographic images and patterns of electromagnetic radiant energy and other phenomena” [15]. The most common photogrammetric application is taking measurements from images to determine tooth size, tooth distances, and other geometric information. As such, it is incumbent upon the analyst to know the sources and solutions for errors of perspective, projection, and such, as well as issues of camera attributes. Forensic odontologists commonly do image comparison through overlays and other methods of comparison. As noted in the SWGIT image analysis document, “photographic comparison is an assessment of the correspondence between features in images and known objects for the purpose of rendering an expert opinion regarding identification or elimination (as opposed to a demonstrative exhibit)” [16]. Domain expertise is of critical importance in recognizing critical features for comparison, knowing artifacts, and interpreting results. Integral within this is content analysis, the drawing of conclusions from an image. Image authentication is “verification that the information content of the analyzed material is an accurate rendition of the original data by some defined criteria. The forensic odontologist must be able to distinguish between “real” features of bitemarks as opposed to issues

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of compression, image degradation, image acquisition, and such. It should be clear from the preceding discussion that bitemark analysis involves both objective statistical and cognitive analytical issues. These should not be conflated. As noted by the SWGIT [17]: Some conclusions can be based on statistical criteria, while other conclusions are based on subjective criteria. Conclusions derived from photogrammetric analyses can often be reported in terms of statistical criteria. In contrast, many conclusions derived from image content analyses are based on subjective criteria. The basis for, and uncertainty of, any conclusion should be reflected in the reporting.

Regardless of the image processing or analysis method employed, the investigator should have sufficient practical and theoretical knowledge of any algorithm used to know what artifacts can be created, how changes in parameterization can be expected to change the image, and potential sources of error. It may not be necessary to have a complete knowledge of the mathematics involved (though that would be optimal), but at least the practitioner should know enough to describe the underlying principles and pitfalls. It is not enough to go to court and merely claim that one hit the “improve” button in a piece of software and then magic happened. Not all forensic odontologists can or should master all algorithms, and not all computer scientists should pretend to know odontology. However, that does not remove the analyst’s responsibility to become sufficiently conversant with the principles of the algorithm and implementation to demonstrate competence to apply it intelligently and to interpret the results correctly. 9.2.3 Literature Review There is currently some debate about the uniqueness and interpretation of bitemarks. This literature review is not intended to address these issues, but rather to demonstrate some of the applications of image processing and image analysis in the discipline. Image enhancement has been shown to be of some use in clinical dentistry. For instance, one method of contrast enhancement has resulted in a small increase in the diagnosis of caries in intraoral radiographs [18,19]. The use of filtering, particularly embossing filters, has been of some value [20]. The most common use of image processing in bitemark evaluation is the creation of overlay images and image mixing and overlay [21–23]. It has become a common method of comparison and, at least under in vitro

conditions, can be used to compare impressions with a high reliability, though cadaver studies have not been as encouraging [24,25]. In one recent article, threedimensional models were created by the use of laser scanners of casts and impressions, although the comparison was done using two-dimensional projections and overlays [26]. A great deal of work has also been done in trying to determine what photogrammetric measurements from images can be used to distinguish bitemarks. Some early attempts were made to use computer vision techniques to create a “similarity index” between dentition and bitemarks, with mild success [27,28]. More recently, Kieser et al. found encouraging results when they used the amount of deformational energy necessary to warp images of scans of casts to match candidate images [29]. Another approach has been to measure the relationship of features to a medial axis [30]. Simple Procrustes distances have been found to have limited value [25]. Contrast enhancement methods have been proposed to increase the visibility of dental features, but without statistical evaluation [31]. Comparisons have been attempted using pseudo three-dimensional elevation maps from grayscale images, again without formal measures of validity [32].

9.3 Standards There are no specific standards for image processing in forensic odontology; in fact, there are few such discipline-wide imaging standards within forensic science in general at the time of this writing. Some disciplines have specific historical standards. For instance, in the United States, the fingerprint analysis community subscribes to a resolution standard of 1000 ppi for scanned latent prints and 500 ppi for 10-print cards. These standards are derived from transmission requirements for the national fingerprint comparison and database system rather than from a scientific determination of comparison criteria. Only afterward were studies published demonstrating the degree of detail to which this actually corresponded [33]. To fill this need, the FBI established scientific working groups (SWGs), of which the previously referenced Scientific Working Group on Imaging Technology is one [34]. The SWGIT has proposed general guidelines for the handling and processing of images for forensic purposes. Over the past few years, these guidelines have been used numerous times in courts in the United States to aid in determining the admissibility of digital evidence. The remainder of this chapter will address the

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application of these guidelines with an eye to digital bitemark imaging. Similar organizations have responded to these needs in the UK through the Home Office, in Australia, and in Canada.

9.4 The Digital Work Flow Pipeline Most digital image processing and analysis tasks fall within a predictable work flow. While there are many variations, it is most simply viewed as consisting of four steps. Images are acquired or received, processed, analyzed, and then a report is generated. Each of these, in turn, consists of substeps—each with specific guidelines. 9.4.1 Images as Evidence Whether or not a given image requires formal evidencehandling processes is a matter of local jurisdictional requirements. In general, primary images (defined later) almost always require careful handling that preserves chain of evidence. In contrast, working images often do not. Whatever the circumstance for a particular jurisdiction, standard operating procedures (SOPs) should be in place to formalize the handling of images for evidence. SOPs must, of course, conform to the requirements of individual jurisdictions. Most formal SOPs include a statement of the name, date, scope, and purpose. Commonly, they delineate the equipment used, the methods of calibration and standardization, known limitations of the method, steps in performing the task, references to the method, and ancillary information [35]. 9.4.2 Image Acquisition and Archival Often, forensic odontologists do not have the opportunity to photograph injuries, but instead receive the images from an outside authority or consultant. In other cases, the odontologist may take the photographs. Proper photographic techniques are addressed in other chapters. Of importance to image processing is the recognition that all methods of digitization involve inherent digital image processing, whether it is the scanning of a photographic print or the use of a digital camera, for instance. This section will concern itself primarily with digital photography. Other acquisition methods have analogous issues. Digital processing is inherent in the conversion from camera sensor signals to pixels forming image data. The basic camera and optional in-camera processing influence the image appearance and may affect interpretability. These settings are often recorded in metadata contained in the image header, as well as other

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data such as time and date stamps and even GPS data [36,37]. But, however they are recorded, they should be noted. It should also be noted that some image processing programs modify or remove metadata; if header data are used as a documentation technique, care should be taken to make sure that they are not lost. 9.4.2.1 Storage Format Storage format is also important. The format must be able to store the data that are acquired. For instance, images may be in pixels with separate red, green, and blue values. The number of colors that can be represented in this representation is a function of the number of bits allocated for each color. Thus, a 24-bit image that stores 8 bits in red, 8 bits in green, and 8 bits in blue can store 28 × 28 × 28 = 255 × 255 × 255 = 16,581,375 colors. Some devices can store 48-bit images. In contrast, some formats can store only a very limited number of colors. For instance, graphics interchange format (GIF) images traditionally store only 255 colors in a “palette” and all pixels in an image use one of those colors [38]. A traditional format developed by the Joint Photographic Experts Group (JPEG) can store a maximum of 24 bits, and common variants of the tagged image file format (TIFF) can store up to 16 bits per color for a total of 48 bits [39,40]. It is important to make sure that the format can represent the data. Most file formats also include some sort of compression algorithm and many allow a choice of compression methods. Some algorithms allow complete reconstruction of the original image data and are called “lossless” algorithms. Some make decisions about what is important data and discard the data considered unimportant; these methods are called “lossy.” Lossy methods usually achieve much greater compression, but at the loss of information. As an example, consider a simple method of compression called “run-length encoding.” In this method, the compression algorithm replaces repeated values by the value and the number of repetitions. Consider the following series: 101 101 101 101 101 100 100 100 101 101 102 102 102 102 102 This series has 15 values and 45 digits. There are five instances of 101 followed by three instances of 100 followed by two instances of 101 and then five instances of 102. If one replaces the original data by a run-length encoding, one gets: 101 5 100 3 101 2 102 5

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Figure 9.6â•‡ Same bitemark, saved using lossless compression (left) and lossy JPEG compression (right), which are visually similar.

This provides a total of eight values and 16 digits—47% compression in terms of numbers and 65% in terms of digits. It is possible to reconstruct the original data from this encoding and it is thus “lossless.” There are a number of lossless compression algorithms, a discussion of which is beyond the scope of this chapter. The most common in use at the moment is TIFF. It should be noted that the TIFF format, often presented exclusively as a lossless format, does allow lossy JPEG compression (described later) in some implementations. Practitioners who use programs that allow JPEG compression in TIFF formats should take care that they are not inadvertently losing data. In contrast, if one makes the assumption that any change of one unit or less is irrelevant, one can replace all the values with 101 in the preceding example, perform run-length encoding, and get the following result: 101 15 This provides a total of two values and five digits—87% compression in terms of values and 89% in terms of digits. However, it is impossible to reconstruct the original data from this encoding. Because data are lost, this is called lossy compression. Of course, practical lossy compression methods are more complex and sophisticated than this simple example, but the effects are still noticeable. A popular compression method is defined by the Joint Photographic Experts Group and is incorporated into two formats: Exif (exchangeable image file format) and JFIF (JPEG file interchange format), both of which are commonly known as “JPEG” formats. JPEG/Exif is more commonly used in digital cameras, though it is not supported by the newer JPEG2000 standard [41]. JPEG compression

segments the image into 8 × 8 pixel squares and a lossy compression algorithm is applied to each square. The user often selects a quality parameter that dictates how much data is discarded. In many cases, the data loss is visually unapparent at higher quality settings, but can still become obvious when the image is enlarged or contrast enhancement methods are applied. As shown in FiguresÂ€9.6–9.8, lossy JPEG compression results in a visually similar image when viewed without enlargement (FiguresÂ€ 9.6 and 9.7); however, the small squares used for compression become obvious upon contrast enhancement and enlargement (FigureÂ€9.8). Most guidelines suggest that images to be used for analysis should be stored using only lossless compression [42]. Most also recognize, however, that the quality requirements of an image are dictated by its use and purpose. For instance, the UK Home Office notes that “the format is not relevant to the admission of the evidence, only that the quality is fit for purpose” [43]. The SWGIT recommends that “the decision to use lossy or lossless compression will be dictated by the intended use of the image” [44]. A photograph used merely for documenting who is at a crime scene, for instance, often does not need to have the same quality as an image acquired for careful analysis of fine detail. Thus, a documentation photograph used merely to show where on the body a bitemark is may not need to be saved in a lossless manner, but a photograph that will be used for performing analysis would be best saved in a lossless format. To avoid the effects of both in-camera processing and compression artifact, some cameras allow the storage of images in an uncompressed, so-called “RAW” format that often stores the actual sensor data and information required to reconstruct a conventional format file. It can also include a low-resolution JPEG format image as part of the file. RAW formats have the advantage of saving data

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Figure 9.7 The images in Figure 9.6 subjected to contrast enhancement.

Figure 9.8 A close-up of a portion of each of the images in Figure 9.7 taken at the edge of the ruler extending downward from the 3-mm mark. Note the 8 × 8 pixel squares in the JPEG-compressed image on the left.

before most, and in some cases all, of the in-camera image processing. It provides the best access to the basic data. The disadvantages of RAW format are twofold. Most important, many RAW formats are proprietary and many require proprietary format for construction of a useful image format file. This may result in format obsolescence and loss of the ability to retrieve the image data if the company goes out of business or decides to discontinue support of the format. Thus, some guidelines suggest the use of RAW format only as an ancillary format or only if it is an open format. For instance, the combined SGIT and Scientific Working Group on Digital Evidence (SWGDE) document on archiving digital and multimedia evidence (DME) notes that “proprietary formats are formats that are primarily supported by the company producing them. These formats may not be supported as new applications become available and

as technology improves. When possible, DME should be retained in its original format and in a nonproprietary format” [45]. The second drawback is more practical. Highresolution RAW images use more disk space and take longer to save in some cameras. This may have an impact on work throughput. This second issue may or may not be of significant impact in any particular situation and will likely be obviated as technology continues to improve. 9.4.2.2 Primary, Original, and Working Images For digital photography, the data produced by the camera are usually stored on some temporary medium such as a magnetic card, though a few cameras can write directly to small optical media. In either case, this is

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conventionally called the “primary” image. Every bitfor-bit copy of that image is considered an original image (as is the primary, of course). In the UK guidelines, the archival copy of the primary image is called the “master” image. This is analogous to the traditional photographic interpretation that every print from a given negative is considered an original print. Most guidelines suggest that the primary image should be copied onto some sort of archival medium before any other processing. All further processing should be performed on copies, which are conventionally called “working copies” [46,47]. 9.4.2.3 Image Integrity and Archival There is an important distinction to be made between image authenticity and image integrity. The verification that a copy of an image data file is the same (by some measure) as the original or primary image is an issue of image integrity: One is showing that the image has not been significantly altered. This is in contrast to the question of whether or not an image actually depicts what it purported to depict which is its authenticity. Image integrity should be maintained as part of the archival process. In general, there should be some sort of verification at the time of archival that demonstrates that the data being stored are, in fact, what they are claimed to be. In some cases, it is adequate to observe the image visually and note that it is visually adequate along with documented security of the physical media. In other cases, it is more convenient simply to create and store some sort of digital signature of the image, such as a hash. A more complete discussion of the following methods can be seen in the appropriate SWGIT document [48]. A hash is a number derived from a data set that provides a digital signature. For example, consider the following numbers: 1234 1235 1334 Let us create a simple algorithm that consists of the number divided by 2 (rounded up), the number divided by 3 (rounded up), and the sum of the digits. Thus, 1234 becomes 61741210, where 617 is the number divided by 2, 412 is the number divided by 3, and 10 is the sum of the digits. Similarly, 1235 gives 61841211, and 1334 gives 66744511. Unlike this example, useful hashing algorithms provide a signature that is significantly shorter than the original data, usually between 64 and 128 hexadecimal integers for a large image. It should also be easily and quickly calculated. As might be obvious, if a hashing algorithm is not carefully constructed, two different numbers might give the same result (and, in fact, one traditional computer science usage of the term hash is to separate

a large number of objects into a small number of bins to aid in searching through them). One popular hashing algorithm is the “MD5 hash,” though collisions (multiple files with the same hash) have been documented [49]. One popular way of proving provenance of images is called “watermarking,” where data are embedded in the image. Some watermarks are obvious, such as logos created by lightening or darkening a part of the image. Many watermarks are not visibly obvious and may only be decoded by the use of specialized software. By definition, watermarks, like lossy compression, constitute intentional image degradation and are not suggested by most standards and guidelines organizations as a method of forensic verification if the image is to be processed or used for analysis. Other mechanisms that aid in maintaining image integrity include written logs of the handling and storage of primary images, physical security of the storage location, redundant physical copies of original images, maintenance of network security for files stored on connected computers, and third-party escrowing. In the latter, the agency turns the data over to a third party for storage. If this method is used, then there should be some way of verifying the third party’s practices. Visual determination of integrity may be adequate, but it demands that the viewer be aware of the contents of the original image. This may be difficult if the question arises years after image acquisition. In the absence of a clear digital signature, it may be necessary to attempt to rule out image manipulation. There are a number of visual cues for image manipulation, including varying positions of incident light, changing degrees of focus, changing color balance, and others. These may not be visually obvious, but they can be detected by examination of image statistics. Within the context of bitemark evidence photography, it is probably best to obviate the need for these more difficult methods by maintenance of integrity within the SOP of the laboratory. 9.4.2.4 Format and Media Obsolescence Of course, the medium upon which the data are stored must be physically protected, and a process should be in place to check and recopy the data periodically before the medium physically degrades. Most media have nominal lifetimes, but most nominal lifetimes assume a particular environment that may or may not be maintained in a given office. Thus, preventative maintenance may prevent loss of data. While this kind of physical degradation of media is intuitive, other kinds of obsolescence must be considered. The first is format obsolescence. The issues with proprietary formats have already been discussed. However, if one reviews the history of digital image

Image Processing and Analysis for Evidentiary Purposes

processing, one can find literally hundreds of image formats that have been popular at one time or another: the TARGA .tga format, the Amiga .ilbm format, the UNC .im format. Today, JPEG, TIFF, and PNG are very popular, but they may not be so in the future. Formats may be encumbered by copyright issues that limit their use [50]. An SOP should be in place to ensure that the formats of archived images remain supported; when that format is no longer supported, the data should be converted. The second type of obsolescence is physical media obsolescence. The author recently had the occasion to review files stored in the early 1990s on so-called “Winchester” disks—an early form of removable hard drive. The disk drives are obsolete and are no longer sold. After days of searching, an old drive was located. It was then discovered that none of the available computers had the necessary (obsolete) port for connection. Eventually, a collector of antique computers was found who maintained hardware that could read the media. An audit at a laboratory in the Washington, D.C., area a few years ago revealed archival data stored on 8-inch “floppy” disks, 5¼-inch floppy disks, 3½-inch floppy disks, Bernouilli disks, ZIP disks, JAZ disks, 8-mm tape, 9-track reel-to-reel tape, CD-ROM optical disks, and DVDs. The laboratory had hardware and software to read only a few of these. A dominant archival medium at the time of this writing is the CD-ROM optical disk. There is no reason to believe that this medium will be common 15 years from now or that most laboratories will be capable of reading data from it. Laboratories that maintain archival media should have SOPs to review their storage media and upgrade as necessary [51]. 9.4.2.5 Image Authenticity Image authenticity, in contrast, often involves knowledge of the subject matter of the image and may require

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viewing of the image. Image authenticity is not an allor-nothing phenomenon. A photograph that superimposes a celebrity’s face on a different body may provide an authentic image of the face, but not an authentic image of the person as a whole. A processed or modified image may still be authentic in the sense of depicting a particular feature or scenario. Determination of authenticity may be an independent image analysis task (e.g., “Is this an authentic photograph of President Lincoln?”) and involve complex analyses, but at the time of archival it is usually simply a check to make sure that the image is what it is supposed to be and is not mislabeled or wrongly filed. Image authenticity at this level can be easily done by visual verification at the time of creation of the archival image and will be carried through by maintenance of file integrity. 9.4.2.6 Image Retention If original images must be archived, the next logical question is, of course, how long one must keep archived images. There is no single answer for this. Different jurisdictions have different requirements defined by law or policy. In the author’s experience, archived images should be retained for as long as review of the case is practical [52]. 9.4.3 Image Enhancement Documentation The image enhancement work flow is often performed as a series of discrete steps. These steps are often not transitive, e.g., the results may be different for the same processes if they are done in a different order. For instance, in the images in Figures 9.9 and 9.10, consider two methods of image contrast enhancement: histogram stretching and adaptive histogram equalization. Figure 9.9 shows an original image and a contrast enhancement method called a

Figure 9.9 A low-contrast image subjected to a histogram stretch.

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Figure 9.10 A low-contrast image subjected to CLAHE.

Figure 9.11 Histogram stretch followed by CLAHE (left); CLAHE followed by histogram stretch (right).

histogram stretch. Figure 9.10 shows the low-contrast image following a contrast enhancement method called contrast limited adaptive histogram equalization (CLAHE). A description of the algorithms is not within the scope of this chapter. However, it is important to note that they are often performed together and the order in which they are performed provides different results. The image on the left in Figure 9.11 is the result of performing the histogram stretch followed by CLAHE; the image on the right is the result of performing the CLAHE followed by histogram stretch. Further, many image processing methods involve a number of parameters, all of which may be set by the user or left as default values. In such cases, a reviewer may not be able to reproduce the results obtained by the original image processing pipeline without knowing these settings. The fundamental guideline is that the degree

of documentation should be sufficient to allow another similarly trained expert to arrive at a similar conclusion. In general, most guidelines suggest some sort of audit trail that will track an image from its creation as a working copy to its final processed status. The Home Office of the UK includes a large number of requirements for its audit trails [53]: The audit trail should include the following information (with date and time of action) when available and if appropriate: • Details of the case • GPMS classification of the image (and any special handling instructions, if relevant) and the name of the person who classified the image • If the image is third-party generated, information about point of transfer including whether the image is the master copy, a working copy or an exhibit derived from a working copy

Image Processing and Analysis for Evidentiary Purposes • Information about capture equipment and/or hardware and software used, including details of the maintenance log relating to capture equipment and calibration of hardware and software • Identity of the capture operative, including third parties and image retrieval officers, where applicable • Details of exhibits and disclosure officers • Description of the images captured, including sequencing • Details of retrieval or seizure process and point of transfer, if applicable • Creation and definition of the master copy and associated metadata • Storage of the master copy • Any access to the master copy • Viewing of the master and working copies, including a record of any associated viewing logs • Details and reasons for any selective capture • Any editing applications that may alter the image • Any details of processing applications allowing replication by a comparatively trained individual • Electronic history log of processing applications • Any copying required to ensure longevity of the data • Revelation to the CPS of the master and working copies • Any copying carried out as part of a migration strategy to ensure the replay longevity of the image • Disposal details and retention time periods

The SWGIT guidelines are not as specific, generally indicating that the documentation should be sufficient for reproduction of results and verification of integrity [54]: “Documenting image enhancement steps should be sufficient to permit a comparably trained person to understand the steps taken, the techniques used, and to extract comparable information from the image. Documenting every change in every pixel value is discouraged because it adds nothing of value to the analysis.” Two special cases often involve questions of documentation. The first involves retention and documentation of abandoned exploration. Image enhancement, particularly for image analysis, is often an issue of image exploration, and exploration often involves following and abandoning blind paths. The analyst may perform a number of processes and find that none of them provides useful insight. Since these paths are not part of the final conclusion, it is not necessary to retain these images or to provide extensive documentation on processes that were triaged and discarded. The second involves the documentation of intermediate images. Consider a simple case of modifying contrast—the equivalent of turning the contrast dial on an old cathode ray television screen (or its equivalent

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on a digital display). Now consider a software application that has an interactive GUI that allows the user to turn a virtual knob and see the result on the display. The user turns the dial until the desired contrast is achieved and saves the result. No intermediate images showing the views provided the user are saved. In contrast, consider a noninteractive, script-based application that simply computes different levels of contrast and writes 100 images to disk, each with an incremental change in contrast. The analyst then uses a viewing program to scan the images and chooses the one that shows the desired contrast. Some have argued that the second investigator should be obligated to save all 100 images, although, of course, the first cannot since no intermediate images are saved to disk (though likely many more are viewed). Clearly, this requirement is nonsensical. Instead, most guidelines require only that final images be retained [55]. 9.4.4 Report Preparation Upon completion of an analysis, a report should be generated. It should include sufficient information to describe and demonstrate results clearly and provide a clear basis for conclusions. Some investigators include sufficient information to allow a similarly trained examiner to come to similar findings in the report itself and do not keep ancillary notes (i.e., the report includes the pertinent information that would be included in notes); others provide minimal process information in the report and keep more detailed notes on file. Both methods are consistent with the current SWGIT guidelines. Because reports of image analysis and image processing often contain large numbers of graphical images, some investigators provide multimedia reports rather than traditional paper reports. The author, for instance, commonly provides graphics presentations in lieu of paper reports, including Web pages and digital presentations. These formats have the advantage of enabling the incorporation of animation and interactive graphics and are often sufficient to act as courtroom demonstrations for testimony. In general, counsel has been satisfied with this, though individual agency policy or local court preference may make a paper report more appropriate.

9.5 Software Resources Image processing and analysis invariably involve the use of software. Sometimes image processing software is included in the purchase of hardware; sometimes it is acquired separately and some analysts program the code

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themselves. If one uses acquired software, then a number of issues become important. The most important, of course, is that the application provides algorithms that are useful to the analyst. It is also sometimes important, however, to have a large variety of tools within the image processing armamentarium rather than just one or two options. It is sometimes useful to have the option to choose among a number of implementations of the same algorithm. At the time of this writing, a few commercial software packages such as Adobe® Photoshop® dominate many forensic odontology laboratories, but a serious image processor might benefit from exploring all the resources that are available [56]. It should be noted that the software packages in this section are mentioned only for illustration and their mention should not be considered a recommendation; This discussion is not meant to discourage the use of the many packages available that are not mentioned. The author has no financial interest in any particular package, uses many packages, and writes his own code for some applications. The following sections discuss a number of features in software packages that one could consider.

apply. However, other algorithms, such as filtering and high dynamic range image formation, are easily applied. Although some packages are generally oriented toward a specific discipline, plug-ins need not be so specific; conversely, some general purpose programs have targeted plug-ins. Many of the software packages discussed in this chapter have good but limited capabilities. The reader should investigate the many resources and see what provides the functionality he or she needs. The important thing to know is that there are many solutions that can be tailored to the needs of the individual laboratory and that the solution may or may not be found in a single package.

9.5.1 Applicability

9.5.3 Validation and Algorithm Description

The program must provide the functions the analyst needs. Some packages concentrate on a few algorithms. For instance, Lucis Pro software is a proprietary plug-in for Adobe Photoshop that focuses on one contrast enhancement method [57]. Some software packages, such as Auto-Measure® by Cognitech and Photomodeler® by Eos Systems, provide image meas urement and photogrammetric capabilities, but little image processing [58,59]. Other products offer a broad armamentarium and/or allow third-party plug-ins. A number of the more common large programs—both proprietary, such as Adobe Photoshop and Image Pro® by Media Cybernetics, and open source, such as GIMP and ImageJ—provide large numbers of integrated capabilities and allow third-party plug-ins [56,60–62]. Some packages are focused primarily on one market, such as astronomy (IRIS® and IRAF), medicine (ImageJ), or microscopy (Pixcavator, Imaris) [63–66]. Most software packages that are oriented toward one discipline have algorithms that can be used for other purposes, but it may not be obvious how to apply them outside the targeted discipline. To use the well-known Richardson-Lucy deconvolution algorithm in IRIS, the software requires the user to pick a small star that is assumed to be a perfect circle. This is used to compute the blurring function. Obviously, if one does not have a star handy, the algorithm would be difficult to

It is necessary that the software package provide enough of a description of the algorithms available for the user to achieve this level of knowledge. Further, the software should lend itself to some sort of validation. One should be able to take known images, perform known tasks, and get predictable results. This will be further addressed in the discussion of open source and proprietary software.

9.5.2 Single Application or Enterprise Solution Some packages are not simple packages at all, but rather large-scale enterprise solutions (for instance, see Vital Images®) [67]. In general, these are large and expensive and are suited for enterprise needs beyond the scope of this chapter. However, a practitioner working within an organization that uses a large enterprise solution may find access to advanced resources.

9.5.4 Graphical Interface and Ease of Use The graphical user interface should be usable and fit into the work flow of the laboratory. It should be noted that interface issues could be deceiving on initial use. Some packages, for instance, are designed for highly intuitive use that makes it easy for a naive user to navigate through options and parameters. However, the very things that make this use easy for the beginner can be frustrating for the experienced user because simple tasks may involve numerous menu choices and mouse clicks. Similarly, some packages have been designed with the “power user” in mind; this means that the beginner has a significant learning curve, but the experienced user is much more productive. Some processing methods are almost impossible without a graphical user interface. For instance, a convenient way of removing periodic backgrounds in images is done by performing a Fourier transform of an image

Image Processing and Analysis for Evidentiary Purposes

that represents the image in terms of sines and cosines. One then manually manipulates coefficients of Fourier transform by painting on the image of the transform, usually removing bright peaks and lines, and then performing a reverse transform. This is very difficult to do in a script-based system. The removal of the linear features in Figure 9.4 was performed by painting away spikes in the image of the Fourier transform of the image. The ability to manipulate a Fourier transform interactively in this way is very difficult without a GUI that supports visualization and painting of an image with complex (in the mathematical sense) data. On the other hand, performing large batch operations such as cropping or simple contrast enhancement on a large number of images can be cumbersome using a GUI and is instead often more easily done using simple scripting language. The most extreme example of this is the “netpbm,” which consists of a series of system calls to be used from the command line. This makes it possible to perform complex image processing on large numbers of images by means of command line script, particularly when combined with other similar tool kits [68]. Many packages with prominent GUIs allow scripting, either by use of a standard scripting language such as python or with their own scripting language. While it contains a GUI, ImageJ is capable of operating through a command-line or scripted interface only. 9.5.5 Programming Requirements As noted before, some imaging software packages incorporate scripting, either as an option with a GUI or as the only option. Some are, in fact, marketed as image processing languages in which the GUI is either optional or constructed from the script. One very popular package with this philosophy is IDL, which originally meant “interactive data language” but is now marketed by its acronym. It is a language that allows scripting of image processing, data analysis, and GUI development within a programming environment [69]. Other examples include the commercial packages MATLAB® and Mathematica as well as the open source GNU Octave and Scilab [70–73]. Other resources are not compiled programs at all, per se, but rather are programming toolboxes, components, or libraries that must be incorporated into programs that the user must code for himself or herself. Two very powerful examples of these are the Visualization Toolkit (VTK) and the Insight Toolkit (ITK). The latter is a set of image processing algorithms developed under contract with the National Library of Medicine to aid in scientific exploitation of visible human data; it is now supported by the NLM and by a growing scientific user

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group [74,75]. Similarly, many programming languages incorporate a number of image processing capabilities within themselves or as associated libraries. Examples include the Java Advanced Imaging API and the Python Imaging Library (PIL) [76,77]. There are multiple image processing libraries for C and C++ programmers, such as the CImg library [78]. 9.5.6 Metaphor Is the user comfortable with the metaphor of the application? Different software programs provide different metaphors for the image processing. Some are monolithic in that the user is presented with a series of options, menus, or buttons and performs operations on the images by sequentially making choices. Examples of this are GIMP®, Adobe Photoshop, and ImagePro®. Others use a data flow metaphor where processes are presented as blocks on a graphical background and are connected by pipes or arrows representing how data will flow between them; some of these allow parallel processing of an image in multiple modules that will then be merged. Examples of this metaphor are commercial packages such as Advanced Visual Systems AVS5® and AVS Express® and open source packages such as OpenDx® and SciRun [79–81]. MATLAB provides a data flow-like interface via its SIMULINK product, which has an image processing box set [82]. Others, such as MayaVi2, use a hierarchical metaphor [83]. 9.5.7 Data Representation Some applications (or modules or plug-ins within applications) work only on 8-bit images; others support 24-, 32-, or 48-bit images. For instance, with the exception of some specific plug-ins, GIMP generally supports a maximum of 24-bit images (though the upcoming version 2.8 is supposed to provide 16-bit per channel support), while Adobe Photoshop has supported it for some time. A “film” version of GIMP called Cinepaint® supports up to 32 bits per channel and is oriented primarily toward video and film manipulation [84]. 9.5.8 Audit Trails Some software packages, such as Adobe Photoshop, have explicit history logs as part of the regular package or as a plug-in [85]. Some laboratories use these for an audit trail, but others believe that they are more confusing than helpful, particularly when there is exploratory processing rather standardized “cookbook” procedures. Obviously, scripted methods can provide documentation by providing the scripts themselves. Data flow methods

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can provide the data flow diagrams and parameterizations. In cases where none of these is appropriate, other documentation is possible without directly involving the software, but instead using the more traditional notetaking documentation. 9.5.9 Third-Party Support Some packages have a specific set of capabilities, but numerous third-party packages can be added to the system as plug-ins or associated programs. Adobe Photo shop has a large number of plug-ins, some of which are specifically directed at the forensic market. GIMP has a large user base and numerous repositories of plug-ins. The same is true of other packages such as MATLAB, OpenDx, VTK®, and more. In the open source environment, many of the actively developed packages leverage on each other. Mayavi2 is essentially a GUI front end for VTK, and SciRun incorporates elements of ITK. 9.5.10 Open Source versus Proprietary Proprietary software is software created by a company and licensed to users for a fee. Open source software is software created by the user community and freely distributed along with its source code. There are intermediate positions between these two extremes, variously labeled “free software,” “open content,” and others. Proprietary software often has some advantages. Frequently, proprietary packages have more polished user interfaces. Often they have better, or at least formal, support. Often they have large user groups and value-added packages and plug-ins. Some proprietary packages have published validation and other technical white papers. Proprietary packages also often have some disadvantages. They are often expensive and require formal, intrusive, and painful license management systems. The algorithms used may be poorly described and without implementation details, and the source code is almost never available. Because the internals of the package are closely held, support may be available only from one source; if that source is not responsive, it may be frustrating. Proprietary issues may inhibit integration into other parts of the work flow. Open source software has its own advantages. The first and most important is that, by definition, the source code—the actual computer program—is available. This means that it is possible to look at how the program is written and see exactly what compromises and assumptions are made in the program. Thus, one can know exactly what the program does; this is simply not possible in a closed source program. Second, almost all open source

programs are free. There is no license management, no restrictions on the number of computers to which it can be applied, etc. Third, because many of these programs are developed at academic or government centers, they may also have associated white papers and validation. Open source has some disadvantages. Because the software is generally supported by a specific user group, support may be spotty, though one business model for open source software is to provide the software free, but provide for-pay support. One feature of open source is seen by some as both an advantage and disadvantage: Very popular packages are often the focus of feverish development and thus have very frequent updates and upgrades. Some users see this as an advantage since new features and fixes are quickly produced; others consider it a type of instability requiring frequent upgrades and maintenance and thus a disadvantage. In many areas, open source and proprietary software are essentially even. First, it is necessary to compare software at similar levels. There are many buggy, poorly maintained open source projects that are essentially personal hobbies of the developers, and there are open source projects that are run by large groups of professional developers who employ modern software engineering practices. Similarly, there are some very bad commercial products, as well as some very good ones. Comparisons should be made between like packages. Using this comparison, good proprietary and good open source software are essentially equally reliable. Both proprietary and open source packages can become orphaned and obsolete. Both often have good update and upgrade schedules. Both can have significant institutional support, and both can be abandoned. Both can have deep market penetration and large user groups or poor penetration and languishing user groups. Its needs, environment, resources, and expertise will determine the solution for a specific laboratory. A laboratory consisting primarily of private-practice odontologists without programming expertise might not be willing to invest in the learning curve necessary to use a programming tool kit. An integrated laboratory with technical and clinical professionals might do well with a visualization language and develop a GUI specific for the needs of the group. A laboratory with extensive resources or access to academic software may prefer proprietary solutions. A laboratory with limited resources might lean heavily toward open source solutions. Many laboratories use a mix of open and commercial software and find that some applications work better for some tasks and other applications for others. It may be appropriate to use a GUI-based program for some work and a scripted toolbox for other tasks. It may

Image Processing and Analysis for Evidentiary Purposes

be necessary to use one particular application because of the need for a specific algorithm or plug-in and to use others for other tasks. The mix of application software most appropriate for a specific laboratory depends upon the needs and resources of that laboratory. The knowledgeable investigator should be willing to look beyond a single product or package for his or her solution. Choosing a software application is not unlike applying an image processing algorithm and interpreting its results. One must become informed and one must make choices and interpretations based on valid and defensible reasoning.

References 1. Stephen M. Pizer, University of North Carolina Depart ment of Computer Science, personal communication. 2. SWGDE/SWGIT digital and multimedia evidence glossary version 2.3 (May 22, 2009), p. 8. 3. National Policing Improvement Agency. 2007. Practical advice on police use of digital images, p. 28. 4. Royal Canadian Mounted Police. Integrated forensic identification services standard operating guidelines (SOGs) 10: Enhancement of crime scene images. 5. Oliver, W. R. 1998. Image processing in forensic pathology. Clinical Laboratory Medicine 18 (1): 151–180. 6. Alink, A., C. M. Schwiedrzik, A. Kohler, W. Singer, and L. Muckli. 2010. Stimulus predictability reduces responses in primary visual cortex. Journal of Neuroscience 30 (8): 2960–2966. 7. Nightingale, E. B., P. M. Chen, and J. Flinn. 2005. Speculative execution in a distributed file system. SIGOPS Operating System Review 39 (5): 191–205. 8. Fayad, L. M., Y. Jin, A. F. Laine, Y. M. Berkmen, G. D. Pearson, B. Freedman, and R. Van Heertum. 2002. Chest CT window settings with multiscale adaptive histogram equalization: Pilot study. Radiology 223 (3): 845–852. 9. Sivaramakrishna, R., N. A. Obuchowski, W. A. Chilcote, G. Cardenosa, and K. A. Powell. 2000. Comparing the performance of mammographic enhancement algorithms: A preference study. American Journal of Roentgenology 175 (1): 45–51. 10. Rapantzikos, K., M. Zervakis, and K. Balas. 2003. Detection and segmentation of drusen deposits on human retina: Potential in the diagnosis of age-related macular degeneration. Medical Image Analysis (1): 95–108. 11. Frye v. United States, 293 F. 1013 (D.C. Cir. 1923). 12. Daubert v. Merrell Dow Pharmaceuticals, Inc., 43 F.3d 1311 (9th Cir. 1995). 13. Scientific Working Group on Imaging Technology. 2007. Section 12. Best practices for forensic image analysis. Version 1.6, p. 1. 14. Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999). 15. The manual of photogrammetry, 4th ed. 1980. Quoted in SWGIT guidelines, section 12. Best practices for imaging practitioners of image analysis. Version 1.6, 2007, p. 1.

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16. Scientific Working Group on Imaging Technology. 2009. Section 16. Best practices for photographic comparison. Version 1.0, p. 1. 17. Scientific Working Group on Imaging Technology. 2007. Section 12. Best practices for forensic image analysis. Version 1.6, p. 9. 18. Sund, T., and A. Møystad. 2006. Sliding window adaptive histogram equalization of intraoral radiographs: Effect on image quality. Dentomaxillofacial Radiology 35 (3): 133–138. 19. Khan, E. A., D. A. Tyndall, and D. Caplan. 2004. Extraoral imaging for proximal caries detection: Bitewings vs. scanogram. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology Endodontics 98 (6): 730–737. 20. Akarslan, Z. Z., M. Akdevelioğlu, K. Güngör, and H. Erten. 2008. A comparison of the diagnostic accuracy of bitewing, periapical, unfiltered and filtered digital panoramic images for approximal caries detection in posterior teeth. Dentomaxillofacial Radiology 37 (8): 458–463. 21. Martin-de las Heras, S., A. Valenzuela, A. J. Valverde, J. C. Torres, and J. D. Luna-del-Castillo. 2007. Effective ness of comparison overlays generated with DentalPrint software in bite mark analysis. Journal of Forensic Sciences 52 (1): 151–156. 22. Kouble, R. F., and G. T. Craig. 2004. A comparison between direct and indirect methods available for human bite mark analysis. Journal of Forensic Sciences 49 (1): 111–118. 23. McNamee, A. H., D. Sweet, and I. Pretty. 2005. A comparative reliability analysis of computer-generated bitemark overlays. Journal of Forensic Sciences 50 (2): 400–405. 24. Sweet, D., and C. M. Bowers. 1998. Accuracy of bite mark overlays: A comparison of five common methods to produce exemplars from a suspect’s dentition. Journal of Forensic Sciences 43 (2): 362–367. 25. Miller, R. G., P. J. Bush, R. B. Dorion, and M. A. Bush. 2009. Uniqueness of the dentition as impressed in human skin: A cadaver model. Journal of Forensic Sciences 54 (4): 909–914. Epub May 26, 2009. 26. Martin-de-las-Heras, S., and D. Tafur. 2009. Comparison of simulated human dermal bitemarks possessing threedimensional attributes to suspected biters using a proprietary three-dimensional comparison. Forensic Science International 190 (1–3): 33–37. Epub June 7, 2009. 27. Nambiar, P., T. E. Bridges, and K. A. Brown. 1995. Quantitative forensic evaluation of bite marks with the aid of a shape analysis computer program: Part 2. SCIP and bite marks in skin and foodstuffs. Journal of Forensic Odontostomatology 13 (2): 26–32. 28. Nambiar, P., T. E. Bridges, and K. A. Brown. 1995. Quantitative forensic evaluation of bite marks with the aid of a shape analysis computer program: Part 1. The development of SCIP and the similarity index. Journal of Forensic Odontostomatology 13 (2): 18–25. 29. Kieser, J. A., V. Bernal, J. N. Waddell, and S. Raju. 2007. The uniqueness of the human anterior dentition: A geometric morphometric analysis. Journal of Forensic Sciences 52 (3): 671–677. Epub March 31, 2007.

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30. Al-Talabani, N., N. D. Al-Moussawy, F. A. Baker, and H. A. Mohammed. 2006. Digital analysis of experimental human bitemarks: Application of two new methods. Journal of Forensic Sciences 51 (6): 1372–1375. 31. Karazalus, C. P., T. T. Palmbach, and H. C. Lee. 2001. Digital enhancement of subquality bitemark photographs. Journal of Forensic Sciences 46 (4): 954–958. 32. van der Velden, A., M. Spiessens, and G. Willems. 2006. Bite mark analysis and comparison using image perception technology. Journal of Forensic Odontostomatology 24 (1): 14–17. 33. Jain, A. K., Chen, Y., and Demirkus, M. 2007. Pores and Ridges: High-Resolution Fingerprint Matching Using Level 3 Features. IEEE Transactions on Pattern Analysis and Machine Intelligence 29 (1): 15–27. 34. Scientific Working Group. http://www.fbi.gov/hq/lab/ html/swg.htm (last accessed April 18, 2010). 35. Scientific Working Group on Imaging Technology. 2004. SWGDE/SWGIT recommended guidelines for developing standard operating procedures. Version 1.0, pp. 2–3. 36. Oracle Corporation. JPEG metadata format specification and usage notes. http://java.sun.com/javase/6/docs/api/ javax/imageio/metadata/doc-files/jpeg_metadata.html (last accessed April 18, 2010). 37. Metadata Working Group. 2009. Guidelines for handling image metadata. Version 1.0.1. http://www.metadataworkinggroup.org/pdf/mwg_guidance.pdf (last accessed April 18, 2010). 38. World Wide Web Consortium. Cover sheet for the GIF89a specification. http://www.w3.org/Graphics/GIF/ spec-gif89a.txt (last accessed April 17, 2010). 39. Joint Photographic Experts Group. JPEG homepage. http://www.jpeg.org/jpeg/index.html (last accessed April 17, 2010). 40. Adobe Corporation. TIFF Revision 6.0. http://partners. adobe.com/public/developer/en/tiff/TIFF6.pdfâ•¯(last accessed April 16, 2010). 41. Standard of Japan Electronics and Information Technology Industries Association. JEITA CP-3451 Exchangeable image file format for digital still cameras: Exif Version 2.2. http://www.kodak.com/global/plugins/ acrobat/en/service/digCam/exifStandard2.pdf 42. Scientific Working Group on Imaging Technology. 2010. Section 9. General guidelines for photographing tire impressions. Version 1.2, p. 2. 43. Home Office Scientific Development Branch. 2007. DigiÂ� tal imaging procedure v2.1. Publication no. 58/07, p. 6. 44. Scientific Working Group on Imaging Technology. 2007. Section 1. Overview of SWGIT and the use of imaging technology in the criminal justice system. Version 3.1, p. 2. 45. Scientific Working Group on Imaging Technology. 2007. Best practices for archiving digital and multimedia evidence (DME) in the criminal justice system. Version 1.0, p. 4. 46. Home Office Scientific Development Branch. 2007. Digital imaging procedure v2.1. Publication no. 58/07, p. 5.

47. Scientific Working Group on Imaging Technology. 2010. Section 5. Guidelines for image processing. Version 2.1, p. 9. 48. Scientific Working Group on Imaging Technology. 2007. Section 13. Best practices for maintaining the integrity of digital images and digital video. Version 1.0, p. 3. 49. Hawkes, P., M. Paddon, and G. Rose. 2004. Musings on the Wang et al. MD5 Collision Cryptology ePrint Archive. Report 2004/264, http://eprint.iacr.org/2004/264.pdf (last accessed April 15, 2010). 50. Battilana, M. C. 2004. The GIF controversy: A software developer’s perspective. http://www.cloanto.com/users/ mcb/19950127giflzw.html (last accessed April 15, 2010). 51. Scientific Working Group on Imaging Technology. 2007. Best practices for archiving digital and multimedia evidence (DME) in the criminal justice system. Version 1.0, pp. 3–4. 52. Scientific Working Group on Imaging Technology. 2007. Best practices for archiving digital and multimedia evidence (DME) in the criminal justice system. Version 1.0, pp. 3–5. 53. Home Office Scientific Development Branch. 2007. Digital imaging procedure v2.1. Publication no. 58/07, pp. 10–11. 54. Scientific Working Group on Imaging Technology. 2010. Section 11. Best practices for documenting image enhancement. Version 1.3, p. 3. 55. Scientific Working Group on Imaging Technology. 2010. Section 11. Best practices for documenting image enhancement. Version 1.3, p. 4. 56. Adobe Systems Incorporated. Adobe Photoshop CS5. http://www.adobe.com/products/photoshop/compare/ (last accessed on April 20, 2010). 57. Lucis Pro. http://www.lucispro.com (last accessed on April 17, 2010). 58. Cognitech Auto-Measure. http://www.cognitech.com/ content/view/59/28/1/1/ (last accessed April 17, 2010). 59. Eos Systems, Inc. http://www.photomodeler.com/index. htm (last accessed April 17, 2010). 60. Media Cybernetics, Inc. http://www.mediacy.com/ (last accessed April 16, 2010). 61. GIMP 2.6. http://www.gimp.org/ (last accessed April 15, 2010). 62. ImageJ: Image processing and analysis in Java. http:// rsbweb.nih.gov/ij/ (last accessed April 19, 2010). 63. Iris: an astronomical image processing software. http:// www.astrosurf.com/buil/us/iris/iris.htm (last accessed April 17, 2010). 64. IRAF: image reduction and analysis facility. http://iraf. noao.edu/ (last accessed April 20, 2010). 65. The science behind pixcavator. http://inperc.com/wiki/ index.php?title=Why_Pixcavator_works (last accessed April 17, 2010). 66. Imaris. http://www.bitplane.com/ (last accessed April 18, 2010). 67. Vital Images. http://www.vitalimages.com/home.aspx (last accessed April 17, 2010). 68. About Netpbm. http://netpbm.sourceforge.net/ (last accessed April 19, 2010).

Image Processing and Analysis for Evidentiary Purposes 69. What is IDL. http://www.ittvis.com/ProductServices/ IDL.aspx (last accessed April 19 2010). 70. MATLAB Image Processing Toolbox 7.0. http://www. mathworks.com/products/image/ (last accessed April 19, 2010). 71. Mathematica Image Processing and Analysis. http://reference.wolfram.com/mathematica/guide/ ImageProcessing.html (last accessed April 19, 2010). 72. Gnu Octave. http://www.gnu.org/software/octave/ (last accessed April 20, 2010). 73. Scilab image toolbox. http://siptoolbox.sourceforge.net/ (last accessed April 20, 2010). 74. Visualization toolkit. http://www.vtk.org/ 75. Insight toolkit. http://www.itk.org/ 76. FAQ: Java advanced imaging API. http://72.5.124.55/ products/java-media/jai/forDevelopers/jaifaq.html 77. Python Imaging Library (PIL). http://www.pythonware. com/products/pil/ 78. The Cimg Library. http://cimg.sourceforge.net/

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Bitemarks as Biological Evidence David Sweet O.C.

10

Contents 10.1 Introduction 10.2 Saliva 10.2.1 Unstimulated Salivary Flow 10.2.2 Stimulated Salivary Flow 10.2.3 Saliva Physiology 10.3 Cellular Content of Saliva 10.3.1 DNA Evidence from Saliva 10.3.2 Locating Saliva Evidence 10.3.3 Stability of Saliva 10.4 Recovery of Saliva 10.4.1 The Double-Swab Technique 10.4.1.1 Supplies 10.4.1.2 Method 10.4.1.3 DNA Sample from the Bitemark Recipient 10.4.1.4 Storage and Transportation 10.5 DNA Analysis 10.5.1 Polymerase Chain Reaction 10.5.2 Postmortem Stability of DNA 10.6 Summary 10.7 Case Examples 10.7.1 Salivary DNA from a Submerged Body 10.7.2 Victim Bites Kidnapper through Clothing 10.7.3 Saliva from Bites Corroborates Conclusions from Physical Comparison 10.7.4 DNA from a Bitemark in Cheddar Cheese 10.7.5 Salivary DNA from a Slice of Pizza Acknowledgments References

10.1â•…Introduction In an attempt to develop objective methods to analyze bitemarks, attention has been focused on the potential use of salivary evidence deposited during biting to identify the perpetrator. Historically, most forensic uses of saliva have relied primarily on the identification of blood group antigens from secretor individuals and, in some cases, on the analysis of isoenzymes and polymorphic proteins present in the saliva or saliva-stained objects found at the scene of a crime [1]. Other substances in saliva have also been used as the basis of identification tests, including thiocyanate ion, nitrite ion and the alkaline phosphatase and amylase enzymes. Tests of the presence in saliva of amylase are by far the most common conventional tests [2]. Amylase tests can be used not only to reveal the presence of saliva in

131 132 132 133 133 134 134 134 135 135 136 136 136 136 136 136 137 137 137 137 137 138 138 139 141 141 142

forensic stains but also as presumptive tests to search for saliva-containing stains, especially on clothing [3,4]. Serologists estimate that approximately 80% of the human population secretes water-soluble antigens called agglutinins in their body fluids (saliva, semen, tears, and perspiration) that can be used to determine the ABH blood group classification of a person [4–7]. Also, finding salivary amylase on an injury site might confirm that the injury is a bitemark when this is not readily apparent from the physical appearance of the wound [8–11]. Previously, it was assumed that a saliva stain from a nonsecretor (20–25% of the human population) could not be typed for blood group agglutinins. But studies have shown that it may be possible to identify the origin of a saliva stain using certain snail antibodies and monoclonal anti-A antibodies, even in a nonsecretor [12]. In most cases, ABH blood group antigens and other

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nondiscriminatory tests have now been replaced with DNA analysis of saliva. Using DNA analysis, it is possible to establish the origin of a sample that is isolated from biological materials [13,14]. It has been demonstrated that saliva, blood, semen, hair roots, tissue, teeth, and bones are good sources of DNA for identity testing [15–20]. The importance of saliva, blood, and semen as sources of valuable evidence is increasing with respect to forensic odontology examinations. Today, it is possible to recognize the location of a bitemark through marks on the substrate and then recover saliva that was deposited at the site during biting. Significantly, due to refinement of techniques using alternative light sources to locate body fluids, it is also possible to find stains of saliva deposited by sucking or kissing, even in the absence of marks from teeth.

10.2â•…Saliva The fluid normally present in the mouth is termed whole saliva. It is a complex mixture derived from four different types of salivary glands. In addition to the parotid, submandibular, and sublingual glands, which are paired, there are numerous minor mucous glands located in most areas of the oral mucosa except the anterior part of the palate and the gingivae [21]. Whole saliva also contains a variety of nonsalivary components such as (a) gingival crevice fluid, (b) epithelial cells and leukocytes in various stages of disintegration, (c) bacteria, and (d) occasionally, dental plaque and food debris [21]. Whole saliva tends to be very viscous, to be heterogeneous, to be contaminated with bacteria and other extraneous materials, and to consist of variable contributions from different glands. The secretions of the major salivary glands differ in composition. The relative contribution of each gland to the mixed saliva present in the mouth varies with conditions and total flow rate [22,23]. Salivary flow is stimulated mainly by unconditioned reflexes (not requiring higher nerve centers) via proprioceptors in the periodontal ligament and the muscles of mastiÂ�cation. Conditioned reflexes, which rely on previous experiences, account for a smaller component of stimulation [24]. Olfactory stimuli, oral pain and irritation, and pharyngeal and psychic factors have also been shown to affect salivary flow rate [25]. Saliva is a viscous fluid that can be drawn out into long elastic threads; this viscosity varies with the degree of stimulation of the salivary glands. For example, stimulation under test conditions by chewing wax that results in secretions mainly by the parotid gland

produces a fluid with a lower viscosity than that of resting saliva [23]. 10.2.1â•…Unstimulated Salivary Flow Several large studies of the unstimulated salivary flow rate in human subjects have been undertaken in the past 40 years. Results from studies by Enfors in 1962, Shannon in 1967, Shannon and Frome in 1973, and Heintze, Birkhed, and Björn in 1983 concluded that the average unstimulated salivary flow rate is 0.3 mL per minute, but the range is very large [26–29]. Many factors affect the unstimulated salivary flow rate. The most important one is the relative hydration of the body. When the water content of the body is reduced by 8%, the salivary flow rate decreases to virtually zero. For a man of 70 kg (comprising about 50 kg of water), 8% dehydration means a loss of 4 L of water. In contrast, hyperhydration will increase the salivary flow rate [26]. Other factors affecting flow rate include body posture (standing or lying will increase or decrease flow rate, respectively), ambient light conditions (darkness decreases flow rate), cigarette smoking, and olfactory stimulation (both increase flow rate). The amount and composition of saliva change during a 24-hour period following a circadian rhythm [26]. Flow rate (FigureÂ€10.1) peaks during the afternoon and drops to its lowest rate during sleep. These changes do not appear to have important implications for the forensic uses of saliva since the minimum flow rate during waking hours does not fall below 0.3 mL per minute. The lowest flow rate, approximately 0.1 mL per minute, occurs during the night.

0.6

mL/minute

132

0.4

0.2 Sleep

0000

1200

0000 Time of Day

1200

0000

Figure 10.1â•‡ Daily circadian rhythm of unstimulated salivary flow. Solid line represents the mean curve and dashed line represents the idealized effect of sleep from 2300 to 0700 hours.

Bitemarks as Biological Evidence Analgesics Anticonvulsants Antinauseants Anti-Parkinson’s Antipsychotics Antidepressants Antihistamines Antihypertensives Antispasmodics Antiarrhythmics Anxiolytics

Antineoplastics Antiparasitics Appetite suppressants Antiemetics Decongestants Diuretics Expectorants Monoamine oxidase inhibitors Muscle relaxants Sedatives Tranquilizers

Figure 10.2â•‡ Drugs that cause reduced unstimulated salivary flow rate. (From Dawes, C. 1990. In Consensus Workshop on Saliva and Dental Health. British Dental Association, County Mayo, 1–18.)

Studies by Dawes and Jenkins concluded that the flow rate of parotid saliva also varies according to a seasonal circadian rhythm, with a peak value in winter [21,22,30]. Flow rate can also decrease as a potential side effect of many drugs [26] (FigureÂ€10.2). 10.2.2â•…Stimulated Salivary Flow Several studies of stimulated salivary flow rate have been completed in healthy subjects [27–29,31,32]. Results show a wide variation between individuals, but it is not possible to compare the results from these studies directly because a variety of nonstandardized stimuli were used. Many factors influence stimulated salivary flow rate. Although results from studies vary, the maximum stimulated flow rate is reported to be 7 mL per minute for whole saliva [30]. The factors influencing rate include mechanical stimulation (chewing in the absence of any taste), acidic tastes (the most potent stimulator of the four taste stimuli), salivary gland size (directly proportional), and foods. For many years it was believed that both the unstimulated and stimulated salivary flow rates decreased with age. This was mostly because studies were completed on institutionalized, medicated patients. But it also has been shown that age has little effect on flow rate in the normal healthy population [26]. For example, a study of 700 people picked at random on a street in Rochester, New York, assessed the stimulated and unstimulated flow rates in people of all ages up to 80 years. The study found stable flow rates across this age range in healthy individuals. Apparently, only people on medication exhibited diminished salivary flow rates [30]. This leads to a basic question: What is the total daily volume of saliva secreted by the average individual?

133

• The minimum unstimulated flow rate over a waking period of 16 hours is about 0.3 mL per minute or a total of approximately 300 mL of saliva. During sleep, the flow rate falls to 0.1 mL per minute, producing about 50 mL [26]. • Studies of the effects of stimulation with various foods on flow rate suggest an average flow rate during chewing of 4 mL per minute. The average time spent chewing each day is estimated to be 54 minutes [30]. Therefore, saliva production stimulated by chewing results in just over 200 mL per day. Therefore, the total daily flow of saliva amounts to approximately 550 mL per 24 hours. This estimate, from Dawes, is much less than the 1000–1500 mL per 24 hours that was concluded from the work of others and extensively quoted in many textbooks [24,25,32–35]. 10.2.3â•…Saliva Physiology Many factors can affect the composition of saliva (FigureÂ€10.3), including which specific gland is producing the saliva. Virtually all amylase in saliva is produced by the parotid glands, whereas blood group substances derive mainly from the submandibular and sublingual glands and minor mucous glands [24,25]. However, the main factor affecting salivary composition is the flow rate. As flow rate increases, the concentration of some constituents also increases (e.g., protein, sodium, chloride, and bicarbonate) and the concentration of others decreases (e.g., phosphate and magnesium) [26]. The parotid gland normally produces 20% of the total volume of unstimulated saliva secretion; the submandibular gland contributes 65%, the sublingual 7–8%, and the minor mucous glands 7–8%. At high flow rates, the parotid becomes the dominant gland, contributing about 50% of salivary secretion [30]. Species Glandular structure Flow rate Duration of stimulation Previous stimulation Biological rhythms Nature of stimulus Plasma composition (diet)

Hormones Pregnancy Genetic polymorphism Antigenic stimulus Exercise Drugs Various diseases

Figure 10.3â•‡ Factors affecting salivary composition. (From

Dawes, C. 1990. In Consensus Workshop on Saliva and Dental Health. British Dental Association, County Mayo, 1–18.)

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The nature of a stimulus that causes an increase in flow rate also has an effect on composition. For example, the taste of salt stimulates the highest protein content. The type of stimulus has virtually no effect on the electrolyte composition.

10.3â•…Cellular Content of Saliva It appears that the cells present in saliva originate from three distinct sources [36]: • Buccal and lingual epithelial cells that are sloughed from the mucosal surface as a normal consequence of mastication • Leukocytes that migrate into the saliva from the gingival fluids and tissues as a consequence of chronic gingival inflammatory disease present in the host • Bacteria that form both the normal and pathogenic fauna of the oral cavity Of the cells present in saliva, epithelial cells occupy the largest volume [37] (FigureÂ€10.4). Watanabe et al. concluded that there are approximately 4 × 105 epithelial cells per milliliter in dentate patients [38]. The majority of these cells are sloughed from the surface of the buccal and lingual mucosa; a minor component is made up of crevicular or periodontal pocket epithelial cells [39]. Exfoliated epithelial cells can be separated from leukocytes by ultrafiltration under pressure and washing the cells with physiological saline [40].

E

E

E PMN

E B

The number of leukocytes in saliva has been widely investigated. Several studies estimate the number at between 1 × 105 and 4 × 105 per milliliter [41–43]. Leukocytes continuously migrate into the dentate mouth at a rate of about one million per minute [40]. The gingival crevice is their major site of entry [44]. The largest component of the leukocyte count is composed of polymorphonuclear leukocytes (PMNs). These cells are derived principally from the gingival crevice with a small contribution from the oral mucosa and the tonsils [39]. In the gingival tissues and gingival fluid, most leukoÂ�cytes have the appearance of intact cells that resemble those present in the blood [45]. Of oral leukocytes, 98–99% is PMN neutrophils and approximately 1% is lymphocytes [44]. 10.3.1â•…DNA Evidence from Saliva Conventional serological methods of analyzing saliva stains are limited to certain traditional marker systems. But several studies have been able to isolate saliva from objects and identify the origin of the stains using genetic typing systems [18,46–52]. In 1993, Ohashi et al. detected 17–500 desquamated buccal cells per microliter (µL) of saliva in experimental samples. Using the polymerase chain reaction (PCR) technique, the origin of the test samples at the D1S80 locus was discriminated [53]. Hochmeister et al. successfully isolated and analyzed genomic DNA from cigarette butts [54] in 1991, and the FBI Laboratory analyzed salivary DNA evidence on envelopes and postage stamps [55]. Also in 1991, Comey and Budowle studied the efficacy of the HLA-DQA1 locus using the polymerase chain reaction on several types of body-fluid stains, including a mixed stain of blood and saliva on clothing. Results revealed that in a mixed stain composed of 10 µL of blood and 10 µL of saliva, the saliva component typed significantly stronger than the blood component. In fact, the typing strengths were only the same when the saliva concentration in the stain ratio was reduced by 10 times with respect to the blood concentration. This illustrates that the DNA typing strength of 1 µL of saliva is equal to 10 µL of blood [47]. The observations of Comey and Budowle point out the forensic significance of DNA from saliva. Subsequently, in 1995, Sweet et al. isolated sufficient salivary DNA evidence to use multiplex PCR-based tests to identify the origin of saliva stains on human skin [14,56,57].

50 µm

Figure 10.4â•‡ Scanning electron photomicrograph of cells

in human saliva. E shows oral epithelial cells. PMN, a polymorphonuclear leukocyte; B, bacteria.

10.3.2â•…Locating Saliva Evidence The presence of saliva is normally implied from the discovery of considerable numbers of nucleated epithelial

Bitemarks as Biological Evidence

cells [58] and a substantial amylase activity [3,11]. Amylase activity is traditionally identified by reference to the hydrolysis of starch [4]. Amylase will also hydrolyze soluble starch–dye complexes. Sax, Bridgwater, and Moore developed a soluble amylopectin–procion red complex. This complex was later precipitated onto pink amylasesensitive paper to detect the location of saliva stains on objects [10,59]. More recently, crime scene analysts from various police agencies and others have investigated the use of alternative light sources, such as ultraviolet lights [60], mercury vapor lights and carbon dioxide, neodymium YAG, and argon ion lasers [61] to isolate and identify latent fingerprints, body-fluid stains, and other trace biological evidence. These search modalities are based on the inherent fluorescence of biological evidence. This technology has revolutionized the detection of salivary stains on human skin because it enables the investigator to locate a saliva stain caused by sucking, biting, or kissing in the absence of marks from teeth. 10.3.3 Stability of Saliva Numerous enzymes from a variety of sources are present in whole saliva. Carbohydrases, esterases, transferases, proteolytic enzymes (e.g., proteinases, peptidases, and ureases), and other catabolic enzymes are produced by the salivary glands, oral microorganisms, and leukocytes or by a combination of these sources [62]. All of these enzymes and other factors, such as temperature, humidity, time, ambient environment, etc., may have a harmful effect on biological evidence through autolytic or climatic processes [63]. But results from both experimental studies and actual casework confirm that significant conclusions can be obtained from saliva recovered under adverse conditions or samples subjected to potentially detrimental laboratory conditions. For example: • Blood group antigens in body fluid stains are often damaged by inclement ambient conditions, thereby making their detection difficult by conventional methods. But saliva stains tested after a period of 2 years were correctly identified in all cases using a dipstick immunoassay method to detect A and B blood group antigens [64]. • The stability of thiocyanate concentration in saliva is of concern to researchers studying cigarette smoking and to forensic analysts. Callas, Haugh, and Flynn studied the possible evaporation of saliva and the deterioration of salivary thiocyanate concentration over a period of 1 year. Foulds et al. in 1994 undertook a similar

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study. In each case, it was concluded that thiocyanate is stable over short storage intervals. For example, it is stable at room temperature for up to 72 hours, frozen at –18°C in airtight containers for 14 days, and for a period of 1 week in the mail in transit to a laboratory [65,66]. • Adams et al. studied bloodstains contaminated with other body fluids using restriction fragment length polymorphism (RFLP) analysis. Whole oral swabs were taken from a set of female subjects and were mixed with aliquots of 3 and 10 µL of semen in an attempt to contaminate the saliva samples [67]. The mixed stains on the swabs were allowed to air dry at room temperature for 5 days prior to analysis. RFLP patterns were identified for each subject, which indicates that saliva did not undergo significant degradation under these conditions. • Walsh et al. conducted extensive tests to recover DNA from fresh saliva and from mixed samples containing saliva subjected to varying storage conditions. DNA band patterns from saliva stored at –20°C for up to 3 weeks were virtually indistinguishable from the patterns obtained from fresh isolates. In fact, RFLP band patterns were developed from mixed stains of saliva and semen stored at –20°C for as long as 2.5 years [18]. • Walsh et al. [18] also reported preliminary results from studies using cotton swabs containing saliva stored at 4°C and 20°C under both dry and humid conditions for a period of 1 week. Apparently, these storage conditions had no effect on the ability to develop DNA patterns from the saliva samples. But samples stored at 37°C for as little as 4 days failed to yield a definitive result.

10.4 Recovery of Saliva Stains from saliva, semen, vaginal secretions, and blood are usually found on clothing and objects at a crime scene. These stains are analyzed in the laboratory after an investigator has recovered the stained exhibit and transported it for analysis. In these cases, a sample of the actual exhibit material (e.g., cloth) is placed in extraction solvents for processing. This results in almost complete recovery of the biological evidence. When the stained exhibit cannot be recovered and submitted for analysis, a representative sample of it must be collected. Many diverse methods to collect salivary evidence have been reported [4,10,46,68–73]. Until the mid-1990s

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forensic odontologists recommended, with varying degrees of success, the use of sterile gauze, moist cigarette papers, or a wet sterile cotton swab to recover saliva from bitemarks. The aim of these methods was to collect blood group data from the site, so a control sample from an adjacent area was always required in addition to the swab directly from the site. In a landmark study, Sweet et al. developed a new method of recovery called the double-swab technique that used a combination of wet and dry sterile cotton swabs to increase the yield of DNA for analysis [74]. The potential problem of contamination of the sample with DNA arising from epithelial cells sloughed from the skin of the bitemark recipient was acknowledged as the most important potential problem, but the double-swab collection method was shown to reduce this contamination risk significantly. The double-swab method is the recommended saliva collection method for stains on skin. It has also been accepted for wider use, including for blood and semen stains on both animate and inanimate substrates. 10.4.1â•…The Double-Swab Technique Following is a description of the double-swab method [74] of collecting stains of saliva and other body fluids from human skin and other substrates. 10.4.1.1â•…Supplies • Two sterile cotton swabs (no preservatives) • Sterile distilled water (3 mL) • Fitzpak swab box (cat. no. 06129; Fitzco Inc., Spring Park, MN: www.fitzcoinc.com) 10.4.1.2â•…Method Dip the head of one sterile cotton swab in sterile distilled water to moisten the tip thoroughly (~10 seconds). Roll the swab head over the saliva stain using circular motions and medium pressure to wash the stain from the surface. Place this swab in the evidence box to air dry thoroughly (≥30 minutes). Within 10 seconds of completing the first swab procedure, roll the tip of the other dry sterile cotton swab over the area of skin that is now wet from the first swab. Use circular motions with light pressure to absorb the moisture from the skin onto the swab head. Place this swab in the evidence box to air dry thoroughly (≥30 minutes). Since the two swabs come from the same site, they can be combined into a single exhibit. Both swabs can

be placed in the same swab box, marked with chain-ofcustody details and submitted to the laboratory. 10.4.1.3â•…DNA Sample from the Bitemark Recipient A known reference sample of DNA is collected from the bitemark recipient to allow interpretation of possible mixtures. This DNA sample can be in the form of a whole blood sample, buccal swab, small section of tissue from the autopsy incision, etc. (any sample that will provide a DNA profile of the bitemark recipient for comparison purposes). Expedited submission of this sample and the saliva swabs to the laboratory for analysis is recommended. 10.4.1.4â•…Storage and Transportation The swabs and the bitemark recipient reference sample should be submitted for analysis as soon as possible. If they are submitted within a few hours of collection, storage and transportation at room temperature are adequate. If the time to submission is longer than several hours, then cold transportation (dry ice or frozen packs) or frozen storage (–20°C) is recommended.

10.5â•…DNA Analysis The primary objective of the odontologist should be to subject bitemark evidence to a complete range of tests in order to reach conclusions that can be used to identify the perpetrator. Conclusions from physical comparison tests are necessarily conditional since a high level of certainty is not possible using such tests, which are subjective. Since it is possible to identify a specific individual using the uniqueness of the DNA molecule, the application of DNA tests to saliva stains recovered from the injury is recommended as adjunctive and corroborative examinations. It is often possible to report the likelihood that a suspect is either implicated by the evidence or should be excluded from further consideration with a much higher degree of confidence than was previously possible. Forensic scientists currently have a number of DNA testing methods that reveal either length-specific or sequence-specific variations in DNA. The method of choice largely depends upon the quality and quantity of DNA extracted from the sample and the DNA reference source available for comparison. Analysis of short tandem repeating units (STRs) in nuclear DNA evidence using PCR-based amplification techniques is the most widely used method today.

Bitemarks as Biological Evidence

10.5.1 Polymerase Chain Reaction The polymerase chain reaction method had a revolutionary impact on DNA analysis methods when Mullis et al. formally introduced it in 1986. The PCR permits a minute quantity of DNA to be amplified by the same basic replication machinery that a cell uses prior to normal mitotic cell division [75–77]; this is completed in the laboratory under tightly controlled and administered conditions. The amplification of DNA fragments today using an automated system has truly changed the detection of DNA sequence variation and the study of the human genome. Using this method, specific human DNA fragments that have significance in forensic science can be selectively amplified in a test tube [78,79]. The technique has two important benefits. First, analysis is possible from very small amounts of DNA. This allows information to be obtained from evidence samples such as a hair follicle, an invisible semen stain [80], swabs from bitemarks, and similarly minute biological samples. Second, amplification is possible from very old material or from degraded DNA. From a practical point of view, the technique is relatively simple to perform and results can be obtained within a short period of time, often within 24–48 hours. For forensic purposes, analysts focus on micro satellite loci in the DNA molecule [81–84]. These loci, called short tandem repeats, are 100–350 base pairs in length with a core repeating unit of two to five base pairs. The PCR products generated during STR analyses are separated and visualized using (a) conventional polyacrylamide gel electrophoresis methods [77,85] or (b) automated robotic gene sequencers. 10.5.2 Postmortem Stability of DNA As the body decomposes following death, the DNA molecules in all parts of the body are presumably degraded by nucleases (enzymes that specifically attack nucleic acids). It is presumed that these nucleases are released with other hydrolytic enzymes as cellular and subcellular membranes lose their integrity after the cell dies [86]. Experiments have demonstrated that DNA contained in a test sample incubated in low-humidity conditions will degrade more slowly than a sample in high-humidity conditions. Variations in temperature also have an effect on the degradation rate; high temperatures appear to accelerate decomposition and degradation [86,87]. Environmental studies conducted by McNally et al. in 1989 showed that dried bloodstains exposed to conditions of varying humidity, temperature, and ultraviolet light for periods up to 5 days did

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not alter the integrity of the DNA and had a significant impact on the ability to analyze the samples [88].

10.6 Summary Data obtained through DNA analysis are objective and, if the analysis methodology has been correctly performed, the resulting conclusions are difficult to dispute. The analysis of DNA extracted from saliva deposited on human skin by biting or through other types of aggressive oral behavior has the potential to identify the biter. Through DNA analysis, results can exclude or include the biter in the events of the crime. There is absolute certainty associated with a DNA result that produces an exclusion of the biter. If the genotype of the saliva does not match the biter’s genotype, then the evidence did not originate from the biter. On the other hand, a result producing an inclusion of the biter is expressed in terms of a calculated probability of a positive match. This probability depends on the relative rarity of this genotype in the population and is referred to as a random match probability. Interpretation of DNA typing tests should be included with probabilities derived from collateral tests of other evidence from a given case. Investigative efforts should not be focused solely on DNA evidence for two reasons. First, the results or probabilities may not be conclusive. Second, in some situations, positive results cannot be interpreted correctly without significant additional information. For example, a stain of saliva may be identified as originating from a specific biter; however, that saliva may have been deposited on the skin with the consent of the victim.

10.7 Case Examples 10.7.1 Salivary DNA from a Submerged Body In October 1995, the nude body of a female homicide victim was found approximately 5.5 hours after it was deposited in a slowly moving river. A human bitemark was found on the right breast of the victim. The injury recorded sufficient detail to allow physical comparison of the bitemark to the dentition of several suspects. Standard bitemark evidence collection protocols were closely followed, including photographs, impressions, saliva collection, and dental impressions from the bitemark recipient. The saliva collection method was the traditional (one wet swab) serological method in common use at the time. Four swabs were made to collect

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saliva deposited at the bite site. Other potential DNA evidence recovered at autopsy included postcoital swabs containing epithelial and sperm cells. Over a period of several months numerous suspects were found and attempts were made to connect the physical and biological evidence to them. All were excluded eventually, although the respective analysts did not know the physical comparison conclusions or the DNA results until later. Eventually a suspect who possessed certain hold-back information that had not been released by the police was arrested. Comparisons of the available physical evidence to this suspect identified him as the probable biter. The DNA extracted from the bitemark swabs was low in volume, so the four extracts were combined into one sample. A PCR-based DNA profile from the saliva evidence was determined to be a mixture of two persons. The major contributor to the mixture was shown to be the bitemark recipient. The suspect identified as the probable biter through physical comparisons was identified as the minor DNA contributor [20]. Additionally, this suspect was identified as the origin of the semen sample taken from the postcoital swab. The DNA profile from the bitemark saliva and the male component of the postcoital swab were shown to be the same. Thus, the suspect was identified as the person who had sex with the victim and as depositor of the saliva. The importance of this case is that a DNA profile was produced from the saliva despite submersion of the body in fresh water for more than 5 hours (FigureÂ€10.5). 10.7.2â•…Victim Bites Kidnapper through Clothing On her way to school one morning in 1995, a 12-yearold girl was pulled through the driver’s side window of a car and abducted. While she was being pulled into the car, the victim bit the male abductor through his dark purple T-shirt. The girl was driven to a remote location where she was sexually assaulted. The victim survived the attack and was able to provide investigators with details of her attacker’s physical description and of his clothing and car. A rape kit was recovered from the girl and no semen was found, but a pubic hair that exhibited a small bloodstain on the shaft was found during the examination. A DNA profile was obtained from the blood and hair. A car fitting the vehicle description was located later the same day parked at a residence. A man fitting the general description of the suspect walked out of the residence to speak to the police officer when the car was being examined. The man’s clothing fit the description given by the victim. Later, the suspect was arrested and examined. A

Figure 10.5â•‡ Bitemark on the right breast of a submerged individual in combination with DNA from saliva presented at trial.

bruise was found under the right armpit in the location of the bitemark described by the victim (FigureÂ€ 10.6, left). A purple T-shirt was seized from the laundry basket at the residence. Examination of the right side of the T-shirt revealed a white substance present on the cloth in the form of a bitemark pattern (FigureÂ€ 10.6, right). This pattern was photographed and tested for the presence of amylase and DNA. An odontologist examined the photographs and determined that the pattern was consistent with a bitemark but the physical comparison of the pattern to the victim’s teeth was inconclusive. DNA results from the root end of the pubic hair produced a mixed profile that showed contributions from both the suspect and the victim. Results from the bloodstain on the hair shaft area produced a profile that matched the victim. DNA results from the bitemark on the T-shirt showed the victim’s profile (FigureÂ€ 10.7). The importance of this case lies in the demonstrated need for the odontologist to consider the opportunity to use salivary evidence to assist in identifying the origin of a bitemark. 10.7.3â•…Saliva from Bites Corroborates Conclusions from Physical Comparison The body of a 31-year-old Hispanic female was discovered in 1996 slumped across the front seat of a parked car.

Bitemarks as Biological Evidence

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Figure 10.6â•‡ Bruise found on suspect’s body that corresponded to location of bitemark described by victim (left). Bitemark pattern present on dark purple T-shirt worn by abductor when victim was abducted (right).

The victim died of asphyxia due to neck compression. Autopsy confirmed that she had been sexually assaulted and beaten. Patterned injuries consistent with teeth marks were found on both breasts, three areas of the abdomen, the lower lip (self-inflicted), left pubic region, and right forearm. Forensic evidence was collected using current recovery methods. A criminalist used the Â�double-swab technique to collect saliva at each of the following patterned injury sites: right breast, left breast, and lower left abdomen. An odontologist photographed the wounds extensively. It was determined that most of the wounds did not show well-defined patterns, but the bitemark on the right breast became the focus of attention because it recorded more detail. A suspect was apprehended and forensic physical and biological comparisons were completed. The odontologist concluded that the suspect’s teeth were the probable cause of the bite injury (FigureÂ€10.8). DNA analysis using the Polymarker system, a dot-blot analysis method, could not exclude the suspect as the saliva contributor on the right breast and abdomen. This case is significant because of the additive effects of the conclusions from both the physical evidence and the biological evidence. 10.7.4â•…DNA from a Bitemark in Cheddar Cheese Two suspects were found and arrested the day after a home-invasion robbery. They were charged with possession of property stolen from the residence. Investigators found no evidence to link the suspects to the scene of the crime that could be used to increase the charges. Along with the homeowners, police discovered a block

of cheddar cheese that was deposited in the living room during the home invasion. One bite had been taken from the piece of cheese before it was discarded. The police stored the cheese at –15°C until it was submitted to the laboratory 10 days later. High-quality physical evidence of the biter’s teeth was recorded in the cheese (FigureÂ€ 10.9, left). It was apparent that the biter exhibited a class II, div. II malocclusion. Attention was focused on one suspect that appeared to have such a malocclusion. The cheese was swabbed using the double-swab technique in an attempt to recover saliva where it was contacted by the lips and tongue. But it was thought that this evidence would not be needed since (a) the physical evidence was very good, and (b) previous attempts to produce a DNA profile from biological evidence on cheeses had been unsuccessful. A warrant to seize dental exemplars from the primary suspect was obtained but the warrant could not be executed because the suspect was not able to contact legal counsel for advice during the time that the warrant was active. Plans to obtain the dental exemplars were abandoned because it was expected that since the suspect was informed that exemplars were required for comparison purposes, he would attempt to alter his teeth before another warrant could be obtained. The laboratory recovered DNA from the double swabs and took measÂ�ures to purify the sample adequately. A full DNA profile was obtained. This was compared to a known DNA sample (blood) from the suspect that was obtained under the provisions of a DNA warrant. The suspect’s genotype matched the genotype from the saliva deposited on the cheese. This identified the suspect as the biter and connected him with the crime scene [19].

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Figure 10.7â•‡ DNA profile of victim (known reference sample) compared to DNA profile from saliva stain on purple T-shirt worn by suspect.

Bitemarks as Biological Evidence

Figure 10.8â•‡ Physical comparison of teeth of suspect to marks from teeth on breast of victim found in car.

The case illustrates an important willingness by the police to attempt DNA testing in such unusual cases or with unusual evidence samples. It is difficult or impossible to predict if a DNA result can be obtained since so many factors can influence the outcome. Despite this, it is still very important to attempt to produce a profile. 10.7.5â•…Salivary DNA from a Slice of Pizza In 2004, two teenaged boys alleged that they were assaulted and that during the assault the attacker had taken a bite out of several pieces of pizza that the boys had been eating prior to the attack (FigureÂ€10.9, right). Three slices of pizza with ham and cheese topping were stored in the police exhibits freezer, where they remained for 18 months. Preliminary investigations to determine the validity of the teenagers’ comments were undertaken. ExaminaÂ� tion of the frozen pizza slices by the forensic odontologist revealed marks on each slice that exhibited the

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characteristics of human bitemarks. A fresh pizza of the same brand and type was purchased and bites were made in several slices and then stored in a freezer for a period of time. After 3 weeks it was demonstrated that a DNA profile matching the known source could be obtained when the pizza was thawed, but it was also noted that dimensional changes in the bitemarks had occurred. Further dimensional changes in the pizza were demonstrated after additional storage for 3 months. Hence, conventional bitemark analysis was approached with caution. After 18 months of elapsed time, the evidence slices were thawed; biological swabs were taken using the double-swab method and the bitemarks were photographed. A comparison of the photographs with digital overlays of a suspect’s dentition demonstrated consistency but was not sufficient to identify the biter conclusively. No exclusionary casts of the alleged victims’ teeth were produced. DNA analysis resulted in a full profile, which was determined to match the exclusionary profile of one of the teenagers. Although in this instance the DNA profile was not related to the alleged offender, the significant feature was the ability of forensic biologists to obtain a DNA profile from a slice of pizza that had been frozen for a considerable period.

Acknowledgments The valuable assistance of the following collaborators is gratefully acknowledged: Robert E. Wood, forensic odontologist, Toronto, Canada; Greggory S. LaBerge and Ted A. Davelis, Denver Police Department Crime Laboratory, Denver, Colorado; Gerald L. Vale, Cathy A. Law, and Gregory S. Golden, forensic odontologists; the minister for police in South Australia; the South Australia Police; Forensic Science, South Australia; and Helen James, Denice Higgins, and Giac Cirillo, Adelaide, Australia.

Figure 10.9â•‡ Single bitemark in block of cheddar cheese recovered from living room after home invasion robbery (left). Multiple bitemarks in a slice of ham and cheese pizza recovered from the scene of an alleged assault (right).

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Bitemarks as Biological Evidence 37. Klinkhamer, J. M. 1968. Quantitative evaluation of gingivitis and periodontal disease. II. The mobile mucus phase of oral secretions. Periodontics 6:253–256. 38. Watanabe, T., N. Ohata, M. Morishita, and Y. Iwamoto. 1981. Correlation between the protease activities and the number of epithelial cells in human saliva. Journal of Dental Research 60:1039–1044. 39. Wilton, J. M. A., M. A. Curtis, I. R. Gillett, G. S. Griffiths, M. F. J. Maiden, J. A. C. Stern, D. T. Wilson, and N. W. Johnson. 1989. Detection of high-risk groups and individuals for periodontal diseases: Laboratory markers from analysis of saliva. Journal of Clinical Periodontology 16:475–483. 40. Raeste, A-M. 1972. Lysozyme (muramidase) activity of leukocytes and exfoliated epithelial cells in the oral cavity. Scandinavian Journal of Dental Research 80:1–6. 41. Calonius, P. E. B. 1958. The leukocyte count in saliva. Oral Surgery 11:43–46. 42. Gilkerson, S. W., H. S. Brown, and G. H. Rovelstad. 1958. Microscopic study of saliva sediment. Research report NM 750126.06.01. Bainbridge, MD: Dental Research Laboratory, U.S. Naval Training Center. 43. Wright, D. E., and G. N. Jenkins. 1968. The differential leukocyte count in human saliva. Archives of Oral Biology 13:1159–1161. 44. Raeste, A.-M. 1972. Morphological changes and lyso zyme activity of neutrophil polymorphonuclear leukocytes in the human dentulous oral cavity. Master’s thesis. University of Helsinki, Finland. 45. Lange, D., and H. E. Schröder. 1971. Cytochemistry and ultrastructure of gingival sulcus cells. Helvetica Odontologica Acta (Suppl.) 6:65–68. 46. Berlin, Y. A., and H. Kazazian. 1992. Rapid preparation of genomic DNA from dried blood and saliva spots for polymerase chain reaction. Human Mutation 1:260–261. 47. Comey, C. T., and B. Budowle. 1991. Validation studies on the analysis of the HLA DQ locus using the polymerase chain reaction. Journal of Forensic Sciences 36:1633–1648. 48. Eriksen, B., and O. Svensmark. 1993. DNA-profiling of stains in criminal cases: Analysis of measurement errors and band-shift. Discussion of match criteria. Forensic Science International 61:21–34. 49. Kauffman, D. L., P. J. Kelle, A. Bennick, and M. Blum. 1993. Alignment of amino acid and DNA sequences of human proline-rich proteins. Critical Reviews in Oral Biology & Medicine 4:287–292. 50. Kloosterman, A. D., B. Budowle, and P. Daselaar. 1993. PCR amplification and detection of the human D1S80 VNTR locus. Amplification conditions, population genetics and application in forensic analysis. International Journal of Legal Medicine 105:257–264. 51. Kojima, T., R. Uchihi, T. Yamamoto, K. Tamaki, and Y. Katsumata. 1993. DNA typing of the three HLA-class II loci from saliva stains [Japanese]. Japan Journal of Legal Medicine 47:380–386. 52. Ovchinnikov, I. V., D. K. Gavrilov, V. V. Nosikov, and V. G. Debabov. 1991. Use of the polymerase chain reaction for typing allelic variants of the human HLA-DQA1

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by hybridization with oligonucleotide probes, specific for specific alleles [Russian]. Molekulyarnaya Biologiya 25:1266–1272. 53. Ohashi, A., T. Aoki, S. Matsugo, and C. Simasaki. 1993. PCR-based typing of human buccal cell’s DNA extracted from whole saliva and saliva stains [Japanese]. Japanese Journal of Legal Medicine 47:108–118. 54. Hochmeister, M. N., B. Budowle, J. Jung, U. V. Borer, C. T. Comey, and R. Dirnhofer. 1991. PCR-based typing of DNA extracted from cigarette butts. International Journal of Legal Medicine 104:229–233. 55. Allen, M., T. Saldeen, and U. Gyllensten. 1994. PCR-based typing of saliva on stamps and envelopes. Biotechniques 17:546–552. 56. Sweet, D. J., M. Lorente, J. A. Lorente, A. Valenzuela, and J. C. Alvarez. 1997. Increasing DNA extraction yield from saliva stains with a modified chelex method. Forensic Science International 83:167–177. 57. Sweet, D. J., J. A. Lorente, M. Lorente, A. Valenzuela, and E. Villanueva. 1997. PCR-based typing of DNA from saliva recovered from human skin. Journal of Forensic Sciences 42 (3): 447–451. 58. Maximov, A. A., and W. Bloom. Textbook of histology. 1970. Philadelphia, PA: W. B. Saunders. 59. Sax, S. M., A. B. Bridgwater, and J. J. Moore. 1971. Determination of serum and urine amylase with use of procion brilliant red M-2BS amylopectin. Clinical Chemistry 17:311–315. 60. Wilkinson, D. A., and A. H. Misner. 1994. A comparison of thenoyl europium chelate with ardrox and rhodamine 6G for the fluorescent detection of cyanoacrylate prints. Journal of Forensic Identification 44:387–402. 61. Auvdel, M. J. 1988. Comparison of laser and high-intensity quartz arc tubes in the detection of body secretions. Journal of Forensic Sciences 33:929–945. 62. Glickman, I. 1958. Clinical periodontology. Philadelphia, PA: W. B. Saunders. 63. Masters, R., and F. Schlein. Factors affecting the deterioration of dried bloodstains. Journal of Forensic Sciences 3:288–302. 64. Rao, D. V., and V. K. Kashyap. 1992. A simple dipstick immunoassay for detection of A and B antigens. Journal of Immunoassay 13:15–30. 65. Callas, P. W., L. D. Haugh, and B. S. Flynn. 1989. Effects of long-term storage on salivary thiocyanate concentration. Addictive Behavior 14:643–648. 66. Foulds, J., A Bryant, J. Stapleton, M. J. Jarvis, and M. A. H. Russell. 1994. The stability of cotinine in unfrozen saliva mailed to the laboratory. American Journal of Public Health 84:1182–1183. 67. Adams, D. E., L. A. Presley, A. L. Baumstark, K. W. Hensley, P. A. Campbell, C. M. McLaughlin, B. Budowle, A. M. Giusti, J. B. Smerick, and F. S. Baechtel. 1991. Deoxyribonucleic acid (DNA) analysis by restriction fragment length polymorphisms of blood and other body fluid stains subjected to contamination and environmental insults. Journal of Forensic Sciences 36:1284–1298. 68. Clark, D. H. 1992. Practical forensic odontology. Oxford, England: Wright.

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69. Cooke, C. W. 1984. A practical guide to physical evidence. Springfield, IL: Charles C Thomas. 70. Lundquist, F. 1962. Methods of forensic science. New York: Interscience Publishers. 71. Mittleman, R. E., W. C. Stuver, and R. Souviron. 1980. Obtaining saliva samples from bite mark evidence. FBI Law Enforcement Bulletin 49 (11): 16–19. 72. Nickolls, L. C., and M. Pereira. 1962. A study of modern methods of grouping dried bloodstains. Medicine Science & Law 2:172. 73. Rothwell, T. J. 1979. Studies on the blood group substances in saliva. Journal of Forensic Science Society 19:301. 74. Sweet, D. J., J. A. Lorente, M. Lorente, A. Valenzuela, and E. Villanueva. 1997. An improved method to recover saliva from human skin: The double swab technique. Journal of Forensic Sciences 42:320–322. 75. Mullis, K., F. Faloona, S. Scharf, R. Saiki, G. Horn, and H. Erlich. 1986. Specific enzymatic amplification of DNA in vitro: The polymerase chain reaction, 263–273. The 51st meeting of quantitative biology. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory Press. 76. Mullis, K. B., F. Ferré, and R. A. Gibbs. 1994. The polymerase chain reaction. Boston, MA: Birkhäuser. 77. Smith, B. C., D. J. Sweet, M. M. Holland, and J. DiZinno. 1995. DNA and the forensic odontologist. In Manual of forensic odontology, ed. C. M. Bowers and G. L. Bell, 283–299. Colorado Springs, CO: American Society of Forensic Odontology. 78. Saiki, R. K., S. Scharf, F. Faloona, K. B. Mullis, G. T. Horn, and H. A. Erlich. 1985. Enzymatic amplification of Beta-globulin genomic sequences and restriction site analysis for diagnosis of sickle cell anemia. Science 23:1350–1354. 79. Saiki, R. K., P. S. Walsh, C. H. Levenson, and H. A. Erlich. 1989. Genetic analysis of amplified DNA with immobilized sequence-specific oligonucleotide probes. Proceedings of National Academy of Sciences 86 (16): 6230–6234.

80. Hegele, R. A. 1989. Molecular forensics: Applications, implications and limitations. Journal of Canadian Medical Association 141:668–672. 81. Edwards, A., A. Civitello, H. A. Hammond, and C. T. Caskey. 1991. DNA typing and genetic mapping with trimeric and tetrameric tandem repeats. American Journal of Human Genetics 49:746–756. 82. Edwards, A., H. A. Hammond, L. Jin, C. T. Caskey, and R. Chakraborty. 1992. Genetic variation at five trimeric and tetrameric tandem repeat loci in four human population groups. Genomics 12:241–253. 83. Boerwinkle, E., W. J. Xiong, and E. Fourest. 1989. Rapid typing of tandemly repeated hypervariable loci by the polymerase chain reaction: Application to the apolipoprotein B 3′ hypervariable region. Proceedings of National Academy of Sciences 86:212–216. 84. Kasai, K., Y. Nakamura, and R. White. 1990. Amplification of a variable number of tandem repeats (VNTR) locus (pMCT118) by the polymerase chain reaction (PCR) and its application to forensic science. Journal of Forensic Sciences 35:1196–1200. 85. Budowle, B., F. S. Baechtel, and D. E. Adams. 1991. Validation with regard to environmental insults of the RFLP procedure for forensic purposes. In Forensic DNA technology, ed. M. A. Farley and J. J. Harrington, 83–91. Chelsea, England: Lewis Publishers. 86. Perry, W. L., W. M. Bass, W. S. Riggsby, and K. Sirotkin. 1988. The autodegradation of deoxyribonucleic acid (DNA) in human rib bone and its relationship to the time interval since death. Journal of Forensic Sciences 33:144–153. 87. Rodriguez, W. C., and W. M. Bass. 1985. Decomposition of buried bodies and methods that may aid in their location. Journal of Forensic Sciences 30:836–852. 88. McNally, L., R. C. Shaler, M. Baird, I. Balazs, P. DeForest, and L. Kobilinsky. 1989. Evaluation of deoxyribonucleic acid (DNA) isolated from human bloodstains exposed to ultraviolet light, heat, humidity and soil contamination. Journal of Forensic Sciences 34:1059–1069.

11

Bitemark Impressions Robert B. J. Dorion Contents 11.1 Introduction 11.2 Materials 11.3 Hair Removal 11.4 Impression Techniques 11.5 Storage References

145 145 146 146 150 151

11.1â•…Introduction The report on bitemark evidence [1] listed the common impression materials used for bitemark impressions in 1977. They included alginate, rubber base, silicone, and hydrocolloid, none of which are in use today for forensic purposes. Other materials employed at the time included plaster of Paris, casting stone, and Silcoset [2]. Various authors have described the different techniques utilized for bitemark impressions on the body [3–6]. The American Board of Forensic Odontology (ABFO) recommends taking dental impressions of the bite site in its guidelines. Photography and salivary swabbing precede impression taking in the bitemark protocol. Normally, the body would be cleaned of contaminants such as sand, soil, and blood prior to the third and fourth set of photographs (crime scene, at the morgue prior to autopsy, undressed, cleaned) and impression taking. The bitemark impression should therefore contain no contaminants. On the other hand, there might be trace residual DNA present in the bitemark impression, which might be transferred to the stone model. Odontologists should be mindful of this possibility.

11.2â•…Materials Specifications for dental materials are regulated and approved by the American Dental Association (ADA) [7]. Materials listed under ADA specification no. 19 are dental elastomeric impression materials. They include polysulfides, polysiloxanes, polyethers, and other nonaqueous materials capable of reacting to form a rubberlike material that can be used for taking impressions. The materials are classed as type I, II, or III according to certain properties after setting. ISO specification

4823-1992 type 1 (low viscosity) and type 3 (low consistency) include vinyl polysiloxanes (VPS). As of this writing, there are currently 466 vinyl polysiloxane commercial brands [8], such as Water Mark (Jeneric/Pentron), Correct (Jeneric/Pentron), 3M Express (3M), Supersil (Bosworth), Aquasil and Reprosil (Densply), Mirror-3 (Kerr), President (Coltene), and Splash (Discus Dental), on the market. Approved for intraoral use, they have also been adopted by a number of forensic disciplines as impression materials of choice. They are employed for shoe and tire prints, for reproducing and capturing tool marks in bone and on cartilage (knife wounds, saw marks, bullet holes, etc.) and inanimate objects (wood, metal, etc.), and for impressions on a variety of other substrates including metal and paper currency and skin. Impression materials have a limited shelf life. It is important to monitor and register both batch (serial) number and expiry date of the material. The manufacturer’s instructions in manipulating the material and recommendations on storage should be followed. Models should not be poured before the recommended time. ADA specification no. 25 deals with dental gypsum products. The current revision is an adoption of ISO standard 6873:1998 and it provides classification of and specific requirements for dental gypsum products used for dental purposes, such as making oral impressions, molds, casts, or dies. It specifies the test methods to be employed to determine compliance with the requirements, the labeling of packaging, and instructions on use to accompany each package. The dental stone’s trade and brand name and the manufacturer’s instructions on water to powder ratio and on pouring should be noted and followed. The initial pour master model should be identified, preserved, and stored in a secure area in a specific container (such as an orthodontic box) as a court exhibit. It can be

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Figure 11.1 Spreading of a depilatory into the skin indentations.

photographed and/or scanned for bitemark comparison purposes. Identified duplicate models can be used for examination, analysis, and testing purposes.

11.3 Hair Removal Hair removal may become necessary to visualize a traumatic injury pattern more clearly. DNA collection must precede any attempts at hair removal. Several methods have been suggested, including the use of electric and handheld hair removal instruments. In addition, cleaning substances such as 98.9% ethanol, detergents, soaps, shaving creams, foams, and chemical depilatories have been used experimentally to evaluate efficacy in facilitating hair removal. When skin indentations are present, the use of any hair removal instrument requiring pressure is contraindicated and a chemical depilatory is preferred. Desranleau and this author [9,10] have concluded that under no circumstances should a chemical depilatory such as Veet® or shaving cream be used at a ring

adhesion site. Figure 11.1 illustrates the use of a chemical depilatory at the bite site. The chemical depilatory is carefully spread with a cotton applicator and left for a period of several minutes, depending upon body temperature. Removal of the substance is accomplished using either a cotton applicator or a 2-inch cotton roll. Figure 11.2 depicts the bitemark indentations following use of the chemical depilatory. Figures 11.3 and 11.4 illustrate the bitemark partially masked by hair and chemical depilatory application followed by alternate light imaging (ALI) photographs of the bitemark.

11.4 Impression Techniques Light-body vinyl polysiloxane (VPS) is injected without pressure from a central point to at least 2 cm beyond the bitemark periphery. A sufficient quantity (1 cm plus) heavy-body vinyl polysiloxane, or putty, is then applied to the 5-mm thick set light-body material. The entire central area of the bitemark may be covered. Some authors have suggested embedding paper clips in

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Figure 11.2 Close-up of skin indentations following the use of a depilatory.

Figure 11.3 Close-up of bitemark indentations during and following the use of a depilatory and a subsequent ALI bitemark photograph.

the heavy-body material to increase retention between it and the backing material. Figure 11.5 depicts “pushing” of the injected light-bodied material ahead of the syringe tip; Figure 11.6 shows an impression putty covering the light-body material and the application of Tak® Hydroplastic® over the impression materials. Tak Hydroplastic has replaced Hygon® as this author’s material of choice for both impression backing and ring construction. The beads (white, pink, yellow, or blue) are heated in a beaker of water to a temperature of 165°–175° in a microwave. The individual beads coalesce

and become transparent when the appropriate temperature has been attained. The blob of material is then manipulated with wet rubber gloves and shaped to form a covering for the set impression material. The hydroplastic hardens during 5–10 min of cooling. Hardening can be hastened with the application of a bag of frozen peas, cold water, or crushed ice. Backing material has also included different acrylics, stone, mesh wire, and custom tray material [11]. Easy Tray custom tray impression material by Kerr is another material. The thermoplastic wafers are

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Figure 11.4â•‡ Close-up of bitemark indentations during and following the use of a depilatory and a subsequent ALI bitemark photograph.

immersed in hot water for 15–30 s. The water temperature must be 170°F (77°C) or greater; this is easily achievable in a microwave. Wafers will adhere to each other and can be shaped to obtain the desired contour. The material is reusable, is not adversely affected by repeated heating, and has an indefinite shelf life. The manufacturer claims the material is 100% dimensionally stable. A method for using the material is described by Dailey, Shernoff, and Gelles [12]. Whatever backing material is used, it should contain some identification (FigureÂ€11.7), such as case number, relationship to anatomical site, date, or other pertinent information. Impressions might contain intricate details of lacerations, indentations, or perforations of the skin associated with the bitemark or other source of trauma, as well as body hair. A vibrator should be used to minimize or eliminate air bubbles when models are poured from bitemark impressions. The die stone or other hard stone should be poured following the manufacturer’s instructions on water/powder ratio. The initial pour master model

should remain pristine for the court. Duplicate models may be made for study, analysis, and testing purposes. All bitemark models are identified, boxed in an appropriate container, registered for date of fabrication (and other pertinent information on the fabrication process) and for chain of possession with the requesting agency, and secured in an appropriate place. Low-viscosity epoxy metallographic embedding medium, such as EpoThin (Buehler, IL), or other forms of acrylic have also been used for SEM studies (Chapter 12) to reproduce dentitions or bitemarks. Another material that has been used for bitemark duplication is S. S. White’s Melotte’s Moldine, a fusible metal melting at 260°F (97°C). The silver-colored material was initially used for making dies and counterdies in dentistry. The material is heated in a crucible with a Bunsen burner or other source of heat and then poured directly onto the impression material. FigureÂ€11.8 depicts three photographs of a Moldine cast of tooth prints on the nose.

Bitemark Impressions

Figure 11.5 “Pushing” light body material into skin indentations.

Figure 11.6 Putty material over light body (upper right) and Tak Hydroplastic (lower left, lower right).

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Figure 11.7â•‡ Bitemark on breast (left), impression (center), and excision ring (right).

11.5â•…Storage

Figure 11.8â•‡ Three views of a Moldine casting of a bitemark on the nose.

Manufacturers of impression materials usually recommend delaying pouring of models for a specific period of time. This allows the material to regain its original shape, particularly when undercuts are present. Additionally, the material may not be completely set, so this provides additional time for the process. Manufacturers do not usually indicate the number of pours that can be made from an impression. Presumably, the fewer the undercuts that are made, the more times an impression may be poured. On the other hand, impression materials were not designed with a postmixing shelf life in mind. There are no recommendations from manufacturers for the storage of set impression materials. What happens to the material over time? At what temperatures and under what conditions should the material be stored? Long-term storage of set dental impression materials may lead to serious complications, as this author can attest. In the early 1970s, rubber base was a material of choice for bitemark impressions. At that time, the set impression material was placed in a box in contact with its stone model. Over time, the set rubber base impression material deteriorated significantly, becoming a “tacky” adherent mass enveloping the stone models (FigureÂ€11.9). Both the impression material and stone models were rendered useless. As a result, this author recommends that each impression be identified, placed in separate sealable plastic bags, and stored separately from its stone models in a container such as an orthodontic box. If the impression material deteriorates, this will not adversely affect the stone models or other materials stored within the container. If the long-term stability of the current set impression materials deteriorates, duplicate impressions can then be made using the original cast stone model.

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Figure 11.9â•‡ Disintegrating rubber base impression material after many years in storage.

This may prove necessary when duplicate or additional stone models are required for study, analysis, or additional tests or to send to colleagues.

References 1. Dorion, R. B. J. Chairman, Committee for Recommended Methods. Odontology Section, American Academy of Forensic Sciences, February 1977. 2. Harvey, W. H. 1976. Dental identification and forensic odontology, 165–166. London: Henry Kimpton. 3. Benson, B. W., J. A. Cottone, T. J. Blomberg, and N. D. Sperber. 1988. Bite mark impressions: A review of techniques and materials. Journal of Forensic Sciences 33 (5): 1238–1243. 4. Vale, G. L. 1989. Discussion of “Bite mark impressions: A review of techniques and materials.” Journal of Forensic Sciences 34 (4): 805–807. 5. Sperber, N. D. 1990. Further discussion on discussions of “Bite mark impressions: A review of techniques and materials.” Journal of Forensic Sciences 35 (4): 777–778.

6. Dorion, R. B. J. 1995. Impressions of the bite site. In Manual of forensic odontology, 3rd ed., ed. C. M. Bowers and G. L. Bell, 170–171. Colorado Springs, CO: American Society of Forensic Odontology. 7. http://www.ada.org/830.aspx 8. http : / / w w w. ne t 3 2 . c om / e c / v i ny l - p olysi lox ane impression-materials-l-524-737 9. Desranleau, S., and R. B. J. Dorion. 2011. Bite marks: Physical properties of ring adhesion to skin—Phase 1. Journal of Forensic Sciences in press (March 2011). 10. Desranleau, S., and R. B. J. Dorion. Bite marks: Physical properties of ring adhesion to skin—Phase 2. American Academy of Forensic Sciences, Seattle, WA, Feb. 25, 2010. 11. McNamee, A. H., and D. Sweet. 2003. Adherence of forensic odontologists to the ABFO guidelines for victim evidence collection. Journal of Forensic Sciences 48 (2): 382–385. 12. Dailey, J. C., A. F. Shernoff, and J. H. W. Gelles. 1995. An improved technique for bite mark impressions. In Manual of forensic odontology, 3rd ed., ed. C. M. Bowers and G. L. Bell, 174–177. Colorado Springs, CO: American Society of Forensic Odontology.

12

Microscopy Techniques Peter J. Bush Contents 12.1 Microscopy Introduction 12.2 Stereomicroscopy 12.3 Replication Technique 12.4 Confocal Laser Microscopy 12.5 Scanning Electron Microscope 12.6 Skin Surface Details Revealed by SEM References

153 153 153 155 155 156 158

12.1â•…Microscopy Introduction Examination of a potential bitemark in skin involves initial visual inspection to determine if class or individual characteristics exist that indicate the presence of a patterned injury caused by the human dentition. The evidence may be in the form of a bruise or abrasions or, more rarely, lacerations or indentations. Occasionally, an instance may be encountered in which it is deemed necessary to obtain magnified imaging of a feature recorded in the skin that may be matched to a feature in the dentition. Modern digital cameras offer optical and digital magnification, which may be sufficient to image toothsized features with sufficient clarity for presentation as evidence. When greater magnification is needed, however, laboratory-based techniques may be of utility. In this chapter, the pros and cons of stereomicroscopy (FigureÂ€12.1, left), confocal laser microscopy (CLM), and scanning electron microscopy (SEM) will be discussed. Advanced microscopy methods rely upon fabrication of faithful reproductions of both skin (FigureÂ€12.1, right) and teeth in a medium that is suitable for the type of microscopy to be performed. Methods of exemplar production that can produce models that contain detail visible at wide ranges of magnification are outlined here. The resolution or level of detail attainable with each type of microscopy varies according to technique.

12.2â•…Stereomicroscopy A research-grade stereomicroscope has a magnification range from 2× to 150×. As the name implies, there are two optical paths (typically one for each eye), resulting in the ability to visualize three-dimensional objects. If a camera is attached, it will be for one optical path only

and the resulting recorded images are two dimensional in nature. Illumination is achieved using ring lights or optical fibers, which allow direct or oblique lighting as needed. Surface detail can be enhanced by oblique illumination. The stereomicroscope is one of the most useful laboratory tools because full-color inspection and imaging can be performed very rapidly. Inspection with this tool forms the first step of a microscopy approach because it can often be determined immediately whether it is necessary to proceed with more powerful techniques, depending on the presence or absence of features of interest. In the author’s experience, documentation of specimens begins with macroscopic documentation, followed by low to medium magnification stereomicroscopy, and then, if necessary, CLM or SEM examination, which produces images with higher resolution or detail. On the scale of imaging needed in the bitemark field, the stereomicroscope is, without doubt, of the first importance.

12.3â•…Replication Technique In order to ensure that any individual characteristics present in either the dentition or skin are recorded faithfully, exemplars that reproduce detail are necessary (FigureÂ€ 12.2). Best practice to date involves taking an impression using a light-body polyvinylsiloxane dental impression medium. The impressions are then replicated as positive models using low-viscosity epoxy metallographic embedding medium such as EpoThin (Buehler, IL) (FigureÂ€12.3, left). The epoxy has very low shrinkage and is used for embedding materials for subsequent cross-sectional grinding, polishing, and microscopy examination. At this stage, if CLM fluorescence mode is to be used, a fluorophore (such as fluorescein dye) can be added to

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Figure 12.1 A stereomicroscope with ring light and fiber optic illuminators (left). Stereomicroscope image of goldcoated epoxy replica of human skin (dorsal surface of hand), 20× (right).

Figure 12.2 Stereomicroscope image of a gold-coated epoxy replica of an anterior tooth. Note the lingual detail visible. The incisal edge has been restored (left). Stereomicroscope image of replicas of tooth and skin bitten by that tooth. A faint surface indentation is visible in the skin (right).

Figure 12.3 Photo of epoxy models of the dentition (left). The cured model (lower left), with added fluorescein dye for CLM imaging (center), gold coated for SEM observation (lower right). SEM image of epoxy replica of the skin (right). The fidelity of the model-making process reveals the scale structure on the hair shaft.

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the epoxy. To achieve positive detail without excessive artifacts (bubbles), it is necessary to degas the epoxy medium after mixing and then again to degas the poured epoxy on the impressions. This is achieved by placing the epoxy medium and poured models successively in a controlled vacuum chamber. This procedure is aided by the fact that the epoxy medium has a long working time (at least 1 hour) and setting time (8 hours) and low viscosity, meaning that intimate replication of surface structure with minimal artifact can be readily achieved. The resulting positive exemplar has details that can be imaged by all the techniques mentioned with a resolution (replication of detail) of smaller than 100 nm. In other words, the results of this procedure are astonishing in terms of the detail recorded.

12.4â•…Confocal Laser Microscopy An exciting and still emerging field has been confocal microscopy in its various forms. In capturing vertical slices of images with high spatial resolution, the advances are promising for revealing qualitative and quantitative three-dimensional information. Applications have been obvious in other areas of forensic science—in particular, inspection of tool marks and weapons. With respect to bitemark analysis, the technique can return useful information with regard to individualization of the dentition. However, as may be expected, examination of the skin may yield little evidence that may be correlated to the dentition due to the viscoelastic properties of skin.

12.5â•…Scanning Electron Microscope In the scanning electron microscope, a finely focused electron beam is scanned in a raster pattern on a sample surface. As the beam scans, electrons are emitted from the surface; the quantity depends on sample morphology and composition. The contrast and brightness in the resulting images may contain morphology or composition information. Simply put, magnification is increased by reducing the area scanned. The images are readily interpreted as microscopic landscapes to the eye. Although advanced methods can be used with the SEM to produce three-dimensional information, it should be noted that typical SEM images are two dimensional in nature (FigureÂ€12.3, right; FiguresÂ€12.4 and 12.5). Samples for SEM inspection must be compatible with the vacuum, and the surface of the sample must be electrically conductive. This is achieved by coating the sample surface with a thin conductive layer—typically, sputtered gold or evaporated carbon (FigureÂ€12.1, right, and FigureÂ€12.2). Another limitation may be sample size; some SEM models are not able to accommodate large samples, such as a whole mandible. The magnification range may also be considered a limitation because the minimum magnification may typically be in the range of 20×–30×. Imaging of an entire incisal edge of a tooth at this magnification will require stitching two or more images together (FigureÂ€ 12.4, right). Prior inspection by stereomicroscopy becomes more important in view of this, and lower magnification images, which act as roadmaps for navigation at higher magnification, may be taken.

1 mm 20X

60 µm 400X

Figure 12.4â•‡ SEM image of epoxy replica of the skin (left). The inset is drawn to scale. The outlines of the cells on the

surface of the stratum corneum are evident. Mosaic SEM image of the incisal surface of a single tooth (right). The detail revealed by SEM imaging can be seen even at this low magnification of 20×. A chip is present in the incisal edge of the tooth. Also evident are wear patterns.

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3000 2000 y (µm) 1000

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Figure 12.5â•‡ CLM image of the incisal edge chip seen in Figure 12.4. The image is colored according to Z-axis depth

(left). CLM image of a replica of bitten human skin. The two bluish areas represent the depressions caused by two adjacent teeth (right).

Reported use of SEM in bitemark casework has been infrequent, but one landmark case—the seminal 1975 California case, People v. Marx—was notable [1]. In this case, although introduction of bitemark evidence was novel, the methods used (microscopy and SEM) were considered established scientific methods. Otherwise, there have been several early reports of the use of SEM [2–4]. It is possible that the potential of microscopy methods has yet to be realized.

12.6â•…Skin Surface Details Revealed by SEM Because SEM is a true surface-imaging tool, images of the skin reveal information principally of the stratum corneum. FiguresÂ€ 12.3 (right) and 12.4 (left) show the level of detail attainable at relatively low magnifications in unbitten skin. In bitten skin, certain indicators may be present and visible by SEM. The stratum corneum has more plastic properties than the underlying viscoelastic epidermal layers. Because it is

200 µm 100X

composed of layers of keratinized cells, it is stiffer and may retain impressions longer than the dermis as a whole. This stiffness also makes the stratum corneum more susceptible to rupture. FigureÂ€12.6 (right) shows parallel microscopic tears in the stratum corneum in an area of bitten skin (epoxy replica of human skin). SEM imaging can also reveal areas of abrasion or absence of stratum corneum. Perhaps the most telling potential of SEM in bitemark analysis is recognition of clothing imprints. In a study presented at the AAFS 2008 Washington meeting, it was shown that clothing imprints (FiguresÂ€12.7–12.9) could persist in bitten cadaver skin for up to 4 days subsequent to the bite [5]. The gross indentations of the bites made in cadaver skin had fully rebounded after 30 minutes, but the stratum corneum retained details of the fabric weave for a much longer period. The detail retained is potentially of such fidelity that a specific fabric type could be identified. The implications of this from a forensic perspective concern whether the victim was clothed and in what type of clothing and that, following an altercation involving a bitemark, DNA might potentially be recovered from clothing.

60 µm 400X

Figure 12.6â•‡ SEM image of an epoxy replica of bitten human skin, 100× (left). Horizontal tears in the stratum corneum are evident (arrows). The tears are parallel to the long axis of the tooth incisal edge. Detail of tears in the stratum corneum, 400× (right).

Microscopy Techniques

157

Figure 12.7 Stereomicroscope image of a mixed-weave undergarment fabric.

200 µm 100X

200 µm 100X

Figure 12.8 SEM image of fabric weave (left). SEM image of replica of human skin, bitten through the fabric at the same magnification (right).

60 µm 500X

60 µm 500X

Figure 12.9 SEM image of replica of human skin bitten through fabric; impression taken immediately after bite (left) and 96 hours later (right). The imprint of the fabric is still evident on the skin surface.

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

References 1. Vale, G. L., G. N. Felando, R. F. Sognnaes, and T. T. Noguchi. 1976. Unusual three-dimensional bite mark evidence in a homicide case. Journal of Forensic Sciences 21 (3): 11. 2. Solheim, T., and T. G. Leidal. 1975. Scanning electron microscopy in the investigation of bite marks in foodstuffs. Forensic Science 6:205–215.

3. Bang, G. 1976. Analysis of tooth marks in a homicide case. Acta Odontologica Scandinavia 34:1–11. 4. David, T. J. 1986. Adjunctive use of scanning electron microscopy in bite mark analysis—A 3-dimensional study. Journal of Forensic Sciences 31 (3): 1126–1134. 5. Phillips, B., and P. J. Bush. The role of the skin in bitemarks. Part IV. Clothing weave transfer. Proceedings of the American Academy of Forensic Sciences, Feb. 18–23; Washington, D.C.

Nonperishables and Perishables Robert B. J. Dorion

13

Contents 13.1 Bitemarks on Nonperishables 13.2 Factors Affecting Bitemarks in Perishables 13.3 Preservation, Storage, and Transportation of Perishables 13.4 Conclusion References

13.1â•…Bitemarks on Nonperishables Personal identifiers on nonperishables can be analyzed for DNA, fingerprints, and bitemarks. The bitemark quality deposited on these objects will largely depend on the substrate. Impressions left in a solid substrate will give better results than those left in a porous one. A defendant was arrested during a police raid on his home while he was attempting to chew and ingest a block of hashish (FigureÂ€13.1). The suspect presented with no anterior teeth, and a positive impression was made of the imprinted hashish. The three-dimensional dental characteristics were compared to the suspect’s dentition for a positive identification. Although this case predates the use of DNA, it vividly demonstrates the application of three-dimensional objects in comparative analysis, despite the fact that few teeth are present. Conversely, the suspect’s dental casts can also be directly applied to the block of hashish for a positive match since the substrate retained its original shape. Styrofoam comes in many thicknesses, shapes, granular sizes, and colors. Teeth can imprint fairly accurately, depending upon the Styrofoam type. Coffee and cold drink cups are the most common forms of Styrofoam objects that are bitten (FigureÂ€ 13.2). This author reported on the use of Styrofoam as an impression media for registering and analyzing a suspect dentition [1]. It is a quick, effective, painless, and cheap method of recording a dentition instantly. It is particularly useful in recording the dentitions of restless children or deceased animals. Bitemarks are not always associated with criminal acts. The following case illustrates a forensic dentist’s contribution to solving a cause of death. A healthy 6-monthold female was found dead in her crib. The autopsy revealed the cause of death as asphyxia and the manner as accidental. The detached distal portion of the synthetic rubber pacifier (FigureÂ€13.3) was found completely obstructing the trachea. The middle photograph in

159 160 162 163 163

FigureÂ€13.3 depicts an end view of the handle portion of the pacifier, while the bottom photograph shows a lateral view of the distal end of the pacifier. A pair of adjacent curved patterns, each measÂ�urÂ�ing ~6 mm, can be seen on the rubber. These imprints were consistent with the mesiodistal dimension of the child’s only two teeth. Authorities questioned the mother, who revealed that the pacifier had been boiled repeatedly despite the manufacturer’s packaged instructions on limiting the procedure. The synthetic rubber had deteriorated upon repeated boiling and the child had bitten and torn off the end of the pacifier. The tragedy could have been averted had the manufacturer’s instructions been followed. Bitemarks left on objects at a crime scene can be valuable evidence for the prosecution. FigureÂ€13.4 (upper left photo) reveals a portion of a complete upper denture and broken pencil found at the scene of a breaking and entering and robbery of an automobile dealership. A suspect was later apprehended with the complementary fragments in the stolen car. While the match of individual fragments (denture/ denture and pencil/pencil) was relatively straightforward, it was interesting to speculate on how the event occurred. If the fracture of pencil and denture occurred simultaneously, it is hypothesized that a left-handed individual placed the pencil in the mouth and bit twice. The uneventful first bite produced the distal notching of the pencil. The second fractured the previously repaired denture and the pencil simultaneously (FigureÂ€ 13.4, upper right). The lower natural teeth, not seen in the photographs, also marked the pencil’s underside at the fracture site. In an unrelated case, a complete upper denture was left at the crime scene. The male homicide victim, a taxi driver, had a full complement of natural teeth. An edentulous suspect was eventually identified as the owner of the denture based on palatal rugae (convolutions on the anterior roof of the palate) comparison. What links the two stories? It is important to remember that personal

159

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 13.1 Block of hashish with dental imprints.

Figure 13.3 Two tooth prints on a pacifier. Figure 13.2 Bitemark on Styrofoam coffee cup.

identifiers, such as complete or partial dentures lost or discarded at crime scenes, must be identified as to ownership.

13.2 Factors Affecting Bitemarks in Perishables Bitemarks in perishables present specific problems for the odontologist. Some of the factors affecting such bitemarks have a commonality with those affecting bitemarks on skin. Webster [2] suggested a method of classification of bitemarks on foodstuff: type 1 on materials, such as chocolate, that readily fracture with a limited depth of tooth penetration; type 2 on materials such as apples, where the bitten piece is removed by fracturing it from the main material; type 3 on materials such as cheese, which show the same features as in type

2 and where there are extensive scrape marks. This is a commendable classification, but it is too general and does not take into account the many variables outlined in Figure 13.5. Dense, semihard chocolate is probably one of the better bitemark impression perishables. Figure 13.6 demonstrates the three-dimensional dental characteristics recorded in chocolate recovered from a crime scene. Not only is this evidence three-dimensionally stable, but an astute odontologist also can direct investigators to the suspect’s dental profile with greater accuracy than would be possible analyzing bitemarks in skin. The effect of this diagnosis is immediate and concise. One cannot obtain the perpetrator’s physical profile from a fingerprint or from DNA. Figure 13.6 illustrates impressions obtained from chocolate left at a crime scene. Regardless of the analyses, it is important to remember that each specialty should contribute where and how it can. Just as important is

Nonperishables and Perishables

161

Figure 13.4 Fragment of an upper complete denture and tooth imprints on a broken pencil.

Perpetrator • Movement • Force of bite • Dentition: Natural Natural and synthetic Synthetic • Class characteristic • Individual characteristic • Occlusion • Horizontal incisal relationship • Dental fractures • Dental anomalies • Single bite • Multiple bites (overlap) • Calculus • Oral flora • Fingerprints • DNA

Object bitten

Recording

Other factors

• Age of object • Size • Weight • Volume • Number of bites • Depth of penetration • Avulsion • Type of material: Solid Semisolid Porous • Surface area exposed

• Accuracy in photography • Accuracy of impression • SEM

• Evidence collection • Preservation • Storage • Transportation • Elapse of time • Extrinsic factors: Chemicals Artifacts Contamination • Environmental factors: Temperature Humidity Ventilation Bacteria Water Foreign material • Entomological activity • Rodent activity

Source: Modified version of a table first published in Dorion, R. B. J. 1982. Journal of the Canadian Dental Association 48 (12): 795–798. Reprinted with kind permission.

Figure 13.5 Factors affecting bitemarks in perishables.

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 13.6â•‡ Bitemark in chocolate and impressions thereof.

the order in which the analysis takes place. Generally speaking, one should go from nondestructive analysis, saving the more invasive and destructive to the last.

13.3â•…Preservation, Storage, and Transportation of Perishables The 45 contributors to the bitemark survey of the American Academy of Forensic Sciences, Odontology Section, in 1977 [3] listed only 13 cases of bitemarks on inanimate objects. Of those, only one case had gone to court. The

bitemarks on inanimate objects were found in the following materials: cheese, apple, sandwich, candy, chewing gum, wood, leather jacket, and baked clay. The report concluded that “the amount of information received was insufficient to form reliable conclusions for evaluating procedural and technical methods employed.” This author has since reported on the results of experiments on the variables of refrigeration and nonrefrigeration and bitten, pristine, and aging foodstuff in sealed and unsealed containers over a 7-day period [4,5]. The food items included apples (FigureÂ€13.7), carrots (FigureÂ€13.8), cheese (FigureÂ€13.7), and a variety of

Figure 13.7â•‡ Bitemarks in apples and cheese.

Figure 13.8â•‡ Bitemarks in chocolate and carrots under various experimental conditions.

Nonperishables and Perishables

chocolate bars (FigureÂ€13.8). The study also included a discussion on the collection of fingerprints, salivary evidence predating DNA evidence, impression techniques, and model production.

13.4â•…Conclusion In summary, the study’s conclusions were predictable. Bitemarks in perishables, particularly fruits and vegetables, were adversely affected. The greater the number of bites, the more quickly the produce dehydrated and the bitemarks distorted. Dehydration of the perishable and distortion of the bitemark occurred more slowly when the material was placed in a sealable plastic bag. The deterioration was further slowed by the placement of the plastic bag in the refrigerator. As a result, transportation of perishables from crime scene to lab should involve a protocol that requires sealable plastic bags for both contamination/crossÂ�contamination and conservation/preservation issues. In addition, the specimens should be transported within a Styrofoam container to protect them from temperature changes. Multiple specimens within the Styrofoam container should be separated by packing material (plastic bubbles). Rudland [6] considered the dimensional stability of bitemarks in apples after long-term storage in a fixative, while, in a dated study, Stoddart [7] concentrated on a method of producing permanent models from bitemarks in perishable substances. Jarvie and Harvey [8] focused on the preparation of models of teeth and bitemarks in food. David, Haugseth, and Hauptle [9] considered the dimensional change in bitten foodstuff and methods of preservation under variable conditions over a 1-month period. The materials studied included apples, cheese, chewing gum, and candy bars. The materials were frozen, refrigerated, immersed in glycerin, or exposed to the air with or without being sealed in Ziploc bags.

163

In conclusion, it would be fair to say that few bitemark cases on perishable and nonperishable materials have been reported in the literature. There has been little research in the field, possibly because bitemarks in perishables have the disadvantage of rapid and potentially extreme distortion of bitemark and substrate. In addition, other means of identification can be obtained from the material—notably, fingerprints and DNA. In cases where bitemark identification is an issue, the type and quality of the substrate will influence the investigator’s ability to arrive at a conclusion.

References 1. Dorion, R. B. J. Styrofoam as an impression material. Presented at American Academy of Forensic Sciences, Las Vegas, Feb. 13–18, 1989. 2. Webster, G. 1982. A suggested classification of bite marks in foodstuffs in forensic dental analysis. Forensic Science International 20:45–52. 3. Dorion, R. B. J. Chairman, Committee for Recommended Methods, AAFS, odontology section. Feb. 1977. 4. Dorion, R. B. J. 1976. Conclusions to research projects in forensic odontology: Preservation and transportation of foodstuff with bite mark evidence. AAFS, odontology section, Washington, D.C., Feb. 16–20, 1976. 5. Dorion, R. B. J. 1985. Preservation in bite mark evidence: Inanimate objects, foodstuff and human tissues. AAFS, odontology section, Las Vegas, NV, Feb. 12, 1985. 6. Rudland, M. 1982. The dimensional stability of bite marks in apples after long-term storage in a fixative. Medicine Science and Law 22:47–50. 7. Stoddart, T. J. 1973. Bite marks in perishable substances. A method of producing permanent models. British Dental Journal 135:285–287. 8. Jarvie, J. K., and W. Harvey. 1976. The preparation of models of teeth and bite marks in food and on bodies. In Dental identification and forensic odontology. The criminologist. London: Kimpton. 9. David, T. J., R. M. Haugseth, and M. B. Hauptle. 2001. A comparative study of methods of preservation of bitemarks in foodstuffs. AAFS, odontology section, Seattle, WA, Feb. 22, 2001.

Collection of Bitemark Evidence B: Invasive Analyses

IV

14

Tissue Specimens Robert B. J. Dorion

Contents 14.1 14.2 14.3 14.4

Introduction Skin Wetness Skin Dehydration Bitemark Removal 14.4.1 Ring Techniques and Adhesion 14.4.2 Tissue Excision 14.5 Tissue Fixation 14.6 Tissue Storage 14.7 Transportation 14.8 Transillumination 14.9 The Microscope 14.10 Histology 14.11 Postfixation and Storage References

167 167 168 168 170 177 178 180 180 180 182 185 186 193

14.1â•…Introduction A pathologist determines whether tissue is normal or diseased. A forensic pathologist has the added duty of deciphering the proximate cause and manner of death. Bitemark recognition is an additional concern. In a like manner, a dentist’s duty is not the same as a forensic dentist’s responsibility. The latter confirms the identity of the presumed/unknown and recognizes, diagnoses, interprets, and compares bitemarks to suspect dentitions. Unless the forensic pathologist also holds a dental degree, it would be prudent to consult with a boardÂ�certified forensic dentist when a bitemark is suspected. With anyone less educated, knowledgeable, and experienced than a board-certified forensic pathologist performing the initial examination and diagnosis of a bitemark, the greater is the need for consultation with a board-certified forensic dentist. The same principles apply to the dental identification of an unknown/ presumed identity, even in the most obvious of cases. Failure to perform basic requirements for a dental identification can lead to disaster. Noninvasive bitemark techniques should always precede the invasive forms. Invasive bitemark techniques should normally be performed on the deceased only. Prior to 1981, pathologists excised bitemarks for two major reasons: (a) to confirm the presence or absence of hemorrhage, and (b) to analyze the cellular components for the “timing” of the bitemark. FiguresÂ€14.1 and 14.2

depict unsupported excised and transected bitemark specimens highlighting tissue distortion and subcutaneous hemorrhage. Failure to preserve tissue in three-dimensional form with the Dorion type V ring excision technique eliminates the possibility of future accurate • Metric analysis of the bitemark (depending upon the degree of bitemark distortion) • Analysis of the relationship between skin abraÂ� sions, erosions, perforations, etc. and the underÂ�lyÂ�ing subÂ�cuÂ�tanÂ�eous hemorrhage by transÂ� illuÂ�miÂ�nation • Direct comparison of the suspect dentition (dental casts, transparent dental casts or overlays) to the bitemark This last point may be particularly significant if a potential suspect is later detained.

14.2â•…Skin Wetness When a body is recovered from an aquatic environment, the skin is wet (hydrated). If a body is recovered from a snow bank, it may be hydrated or dehydrated in addition to being frozen. Allowing the body to attain room temperature and to dry out may reveal important information that might otherwise be imperceptible. The body

167

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 14.1â•‡ Unsupported excised breast tissue and transected bitemark from an arm.

Figure 14.2â•‡ Excised tissue from a bitemark. (Courtesy of Dr. Richard Souviron.)

wetness may conceal abrasions, including bitemarks. As a body dries, the contrast between abraded and nonabraded skin becomes more apparent. FigureÂ€ 14.3 (left) reveals the wet breast of a female homicide victim retrieved from a river. As the breast dries (FigureÂ€14.3, right), the surface markings become more apparent. One should then further distinguish the surface markings as abrasions from skin creasing, wrinkling, or cellulite. Chapter 15 has an example of skin abrasions on the neck from a victim retrieved from water (FigureÂ€15.1).

14.3â•…Skin Dehydration Postmortem desiccation is a serious complication in patterned injury assessment. Skin can change color, texture, and shape. The breast configuration and trauma in FigureÂ€14.4 (left) cannot readily be visualized or identified. The deceased had been wrapped in a rug for several

days in an abandoned apartment. At autopsy, the breast was excised using the Dorion type II technique at that time and rehydrated in a 50% solution of water and glycerin for 1 week (FigureÂ€14.4, right). Following rehydration, the specimen had partially regained its color, texture, and shape before insertion into a standard fixative. The breast was rephotographed normally and microscopically. Prior to treatment, it was thought that the indentations and abrasions could have resulted from tooth imprints. That evaluation was quickly dismissed when the treated specimen was viewed by microscope. The cause of the repetitive, linear, fine parallel abrasions was ascribed to a razor blade.

14.4â•…Bitemark Removal Bitemarks and other patterned injuries are often removed as part of an autopsy protocol. Sopher, the

Tissue Specimens

169

Figure 14.3 Breast of a victim removed from water (left) and air dried (right).

Figure 14.4 The breast before (left) and after (right) rehydration.

medical examiner/pathologist and dentist, remarked in 1993 that it is the responsibility of the pathologist to recognize a patterned injury as a bitemark, to notify the dental consultant immediately, to use the proper procedures regarding the bitten tissue or substance, and to recover possible secretor substances coating the bitten tissue [1]. Giannelli reports a court ruling in 1984 in which a pathologist testimony that a bruise discovered during an autopsy was consistent with a bitemark was improper because the pathologist was not qualified in forensic dentistry [2]. The judgment to excise suspected bitten tissue is the forensic dentist’s decision to make and the coroner’s,

medical examiner’s, or pathologist’s to approve. Since the coroner, medical examiner, or pathologist is the person ultimately responsible for approving excision, it should be noted that failure to grant permission to excise might be considered by the courts, licensing or certifying body, or specialty as professional misconduct, negligence, or incompetence—to say nothing of the potential loss of information that could have ultimately led to the conviction of the bitemark perpetrator. In a recent article, McNamee and Sweet [3] report that 87.5% of diplomates of the American Board of Forensic Odontology excise the bite site.

170

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 14.5â•‡ Unsupported excised skin. (Courtesy of Dr. Richard Souviron.)

14.4.1â•…Ring Techniques and Adhesion It is known and well documented by forensic pathologists and dentists that unsupported excised tissue may shrink by 50% or more (FigureÂ€14.5). In 1981 a method was developed of fixing a ring to the excised tissue. The hypothesis was that the ring would support the tissue, acting as an exoskeleton, and thus minimize or eliminate tissue distortion. The malleable plastic ring Hygon®, formed by mixing powder and monomer liquid, hardens by exothermic reaction. Hygon is a dental material used in the fabrication of individual trays for dental impressions in prosthodontics. When the ring is formed, cyanoacrylate Krazy Glue® is applied to the ring facing the skin—a technique that became known as the Dorion (type I) technique and that was the first in a series of adaptations currently numbering five (type V). When fixed, the ring is marked for orientation and identification purposes and the tissue excised with the ring. Identification information includes the case number, the date, the examiner’s initials, and the orientation of the specimen to the body as examples (FiguresÂ€14.6 and 14.7). FigureÂ€ 14.6 depicts ring placement on the throat (upper left), breast (upper right), pubis (lower right), and shoulder (lower left). FigureÂ€ 14.7 displays ring placement and excision on the shoulder (upper left, lower left) and arm/elbow (upper right, lower right). In 1981, a variety of specimens of known dimension were collected, including tattoos (FigureÂ€14.8). They were photographed, excised with a ring, fixed, stored, and periodically monitored for dimensional change and stability (FigureÂ€ 14.9). Other skin specimens collected included those containing stab wounds, ballistic injuries, tire marks, and bitemarks. The pre- and postexcision/ fixed bitemark was monitored by direct measÂ�ureÂ�ment of the specimen, using scaled photograph comparisons, and/or by bitemark impression comparisons. The results were rarely found in the scientific literature because scientific sessions and conferences served as reporting medium [4–21].

TAK® Hydroplastic® replaced Hygon as the material of choice for ring fabrication. TAK is a thermoplastic that softens in hot water (145°F–180°F). The 4- to 5-mm beads come in a variety of colors: white, yellow, pink, and blue. The water is microwaved in a beaker until the opaque beads coalesce to become semitransparent. The hydroplastic rehardens in 5–10 minutes with <1% shrinkage. Maximum rigidity is obtained with 4- to 5-mm thickness—well below the recommended thickness for ring fabrication. As previously mentioned in another chapter, TAK is also used as a backing for bitemark impressions. The advantages of TAK Hydroplastic over Hygon include: • • • • •

TAK is self-contained. No mixing of powder and monomer is necessary. No exothermic reaction takes place. There is no smell. TAK can be remolded and reused.

In the 1990s, a modified ring technique making use of Hexcelite® orthopedic tape was developed. Hexcelite is cut in the form of a ring, water-heated in a microwave, and adapted to the required shape encircling the bitemark. One of the disadvantages of Hexcelite tape is that it distorts when cooling. The material must be heated and cooled several times to attain the desired shape to conform to the tissue outline. When the proper form and curvature are achieved, Krazy Glue gel®, rather than plain Krazy Glue, is used to fix the Hexcelite to skin. The adherence is verified making sure that the entire meshwork is attached. Krazy Glue is reapplied as necessary. A previously prepared TAK Hydroplastic ring is slightly reheated and applied to the fixed Hexcelite. Once the ring has hardened, adherence is verified. Krazy Glue gel may be reapplied when necessary. The advantage of this technique over the former one is that mechanical and chemical bonds are established between orthopedic tape and ring.

Tissue Specimens

171

Figure 14.6â•‡ Ring placement on the throat (upper left), breast (upper right), pubic area (lower right), and shoulder

(lower left).

Another application for Hexcelite orthopedic tape involves its use for large specimens that centrally sag owing to either thinness or bulk. Examples include a massive breast or a large but thin skin specimen from a child’s abdomen. Following ring construction with TAK, Hexcelite, and Krazy Glue gel, additional tape is cut to form a matrix (meshwork) supporting the skin side of the ring. The tape is shaped in the usual manner and temporarily bound to the ring and/or the skin with an adhesive that does not contain cyanoacrylate. The additional meshwork support is then removed after fixation. Another proposal for ring fabrication made use of acrylonitrile-butadiene-styrene (ABS) rather than acrylic [22]. Unfortunately, ABS is a difficult material to manipulate, is limited in the number of sizes available, and does not easily achieve the desired contours of the specimen to be excised. This is particularly significant for bitemarks on highly curved surfaces.

In 2005 an adaptation to the ring technique replaced the Hexcelite with mosquito fiberglass netting (Phifer Wire Products Inc., Tuscaloosa, AL) (FigureÂ€14.10), and Krazy Glue gel with Loctite® cyanoacrylate (Henkel Canada, Brampton Ont., Canada). The fiberglass mesh encircles the bitemark and the Loctite cyanoacrylate is centrally placed along the mesh (FigureÂ€ 14.11) and spread with a 2-inch cotton roll or cotton tip applicator. TAK Hydroplastic is applied and cooled (FigureÂ€14.12). FigureÂ€14.8 depicts tattoos excised/fixed in 1981 and rephotographed (FigureÂ€14.9, left) in 2002. The ring is still attached to the tattooed specimen, and there was virtually no dimensional change in 21 years. Not all supported excised specimens experience the same fate, however. Some rings have detached from the skin (FigureÂ€ 14.9, right). So why do some detach while others do not? Until recently, there were only practical indications attributing ring detachment to three principal

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 14.7â•‡ Ring placement and tissue excision on a shoulder and arm/elbow.

factors: temperature, humidity, and the cyanoacrylate itself. Removal of a body from a refrigerated unit necessitates that it attain room temperature before ring fabrication. Complete removal of humidity, condensation, and wetness from the skin to be excised is another important attribute. Finally, the cyanoacrylate must be “fresh,” which means opening a new tube of material and discarding the unused portion. Other cyanoacrylates such as the Gripper®, Avdel Bond 2®, and Krazy Glue and its gel counterpart have been used. Although the manufacturer does not suggest that there is a limited shelf life, it is preferably stored in the freezer or refrigerator and brought to room temperature prior to use. When a bitemark case presents itself, that is not the time to scrounge for the required material. It is important to keep an appropriate supply and periodically to verify the expiry date when it exists. These were the recommendations in the first edition of this book, and only recently have empirical studies on the properties of ring adhesion to skin been conducted [23,24]. They compared various bonding materials (Loctite Supergel®, Dermabond™, Vetbond™, Permabond®, Threebond®, and Krazy Glue), cleaning agents (ethanol, dishwashing liquid, and shaving cream), and a depilatory (Veet®) on the effects of ring adhesion

to skin. The researchers adapted the TriggerScan™, an instrument developed to measÂ�ure tension or compression characteristics of firearms, to measÂ�ure force versus displacement of skin adhesion of cyanoacrylate to the ring (FiguresÂ€14.13 and 14.14). Phase I of this multilevel research studied the amount of tensile stress needed to rupture the bond between the TAK Hydroplastic excision ring, the cyanoacrylate glue or gel, and pigskin (FigureÂ€ 14.15). The pigskin varied from untreated and hairy to shaved. The skin was treated with various materials, including dishwashing detergent, shaving cream, ethanol, and Veet. The room temperature and humidity were controlled, the skin condensation or wetness removed, and various commercial “fresh” cyanoacrylate glues and gels utilized (Loctite Supergel, Dermabond, and Vetbond). The physical properties of the various materials used were assessed with regard to skin adhesion. Phase II dealt with the following: • Studying the amount of the tensile stress needed to rupture the bond between TAK HydroplasÂ� tic, three new cyanoacrylates (Permabond, Threebond, and Krazy Glue), and the pigskin

Tissue Specimens

173

Figure 14.8â•‡ Tattoos excised, transÂ�illumÂ�iÂ�nated, and fixed in 1981.

that was previously shaved and cleaned with dishwashing detergent and ethanol; special consideration was given to the temperature factor (tested with Permabond) • Comparing histologically the differences in pig skin when untreated and treated and cleaned with various agents, including Veet

• Comparing the solubility of different cyanoacrylate glues in formalin 10% • Testing the Dorion type V technique and its modifications on the TriggerScan with different cyanoacrylate glues (FigureÂ€14.16) It was concluded from the empirical results that the risks of tissue distortion and loss of adhesion during

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 14.9 Tattoo excised/fixed in 1981 and photographed in 2002 (left). Breast specimen showing ring detachment 5 years after excision (right).

HEXALITE

FIBERGLASS MESH

Figure 14.10 Hexcelite and mosquito fiberglass netting.

bitemark excision could be significantly reduced by utilizing the recommended techniques and materials. There were six recommendations:

6. The Dorion type V excision technique is currently a viable and scientifically tested method of choice for ring adhesion to skin.

1. The corpse should be left uncovered at room temperature for a period of time prior to ring fabrication. 2. The surrounding skin should be razor shaved and cleaned with dishwashing detergent and ethanol 98.9% for degreasing and surface dehydration. 3. A chemical depilatory, such as Veet, and/or shaving cream should never be used to clean the surrounding skin. 4. A fresh (unopened) cyanoacrylate should be used. 5. A gel ethyl-cyanoacrylate, preferably Permabond, should be used in a very thin layer.

Some authors suggest suturing the ring to the skin as an additional means of retention. The technique may inadvertently create distortion of the excised tissue because some sutures may be more tightly drawn than others. It would not matter whether single or continuous sutures were used if distortion results. There have not been longterm studies on the effects of the sutured ring technique. Rothwell and Thien [26] studied the dimensional stability of excised tissue utilizing a prefabricated template approximating bitemarks in Hanford pigs. The sutured acrylic ring specimens glued with cyanoacrylate were stored in 10% formalin, and measurements were taken

Tissue Specimens

175

Figure 14.11 Fiberglass mesh placement (upper left, upper right) and cyanoacrylate gel application (lower left, lower

right).

Figure 14.12 Placement of TAK Hydroplastic to the fiberglass mesh and skin.

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 14.13â•‡ TriggerScan adapted to measÂ�ure adhesion of ring to skin studies.

BASKET

®

TAK HYDROPLASTIC

CYANOACRYLATE

PIGSKIN

Figure 14.14â•‡ Diagram showing the setup for the experiment.

4.0 3.5

Force (pounds)

3.0 2.5 2.0 1.5 1.0 0.5 0.0 0.00

0.05

0.10

0.15

0.20

Travel (inch)

Figure 14.15â•‡ Graph showing force and displacement.

0.25

0.30

0.35

Tissue Specimens

177 50 45 40

B

Force PSI

35 30

A

25 20

H

15 10 5

O RI D

O

ER

M

N

A

BO

TY PE

N

5

D

D N O D

A RM PE

VE TB

BO

N

D

TI TE C

LO

G ZY A KR

TH

RE

EB

O

N

LU

E

D

0

Figure 14.16â•‡ Graph showing the different cyanoacrylate results and Dorion type V technique.

for 38 days. The data confirmed this author’s findings that a wide range of distortion is expected—from dimensionally stable to contraction and expansion of specimens. However, this author questions the conclusions drawn from this now dated study that “it appears that standard techniques for storage and preservation of bite mark samples do not produce reliable dimensional accuracy.” The dimensional stability of the acrylic ring material (Formatray) used in the study is untested as well as the effects of suturing. The removal of the underlying subdermal tissue before fixation is not what is recommended here as standard technique. FigureÂ€ 1 in Rothwell and Thien’s article [26] demonstrates that the pig had already been sectioned in various parts of the body before the stamp and acrylic ring were applied. What were the effects of this preexisting sectioning, rigor mortis, tension lines, etc., on the results? Was the experimental animal refrigerated, frozen, etc.? The authors point out that “other distortion factors in the indentations themselves and changes in skin coloration made measÂ�ureÂ�ments difficult and in some cases were virtually impossible” and that “the experimental ‘bites’ made in this study are not directly analogous to those seen in the majority of cases investigated in human skin bite marks.” 14.4.2â•…Tissue Excision Tissue excision (FigureÂ€ 14.17) should incorporate the entire layer of fat below the skin (FigureÂ€14.8). If there is bleeding within the muscle, it should be noted and photographed (see FigureÂ€18.61 in Chapter 18). If the excised specimen contains muscle fiber, it should be removed

(FigureÂ€14.18). Inflammatory response in the form of a vessel engorgement and/or hemorrhage in the fat should be noted, transÂ�illumÂ�iÂ�nated [25], and photographed. If the layer of fat is thick (FigureÂ€14.8), gradual layer removal should be achieved until vessel engorgement and/or hemorrhage is observed, noted, transÂ�illumÂ�iÂ�nated [10], and photographed. The absence of vessel engorgement and/or hemorrhage should also be noted. In the circumstance where there is hemorrhage in fat, it should be left intact but the adjacent fat removed (see FiguresÂ€22.4 and 22.5 in Chapter 22). Dimensional stability of ringed excised specimens is influenced, in part, by the following factors: • Temperature and humidity of the specimen prior to excision • Size of the excised specimen (width and thickness) • Dimensional stability of the ring • Type and age of the adhesive • Adherence of the ring to skin (without suturing) • The fixative • Time allotted for fixation • Storage conditions • Postfixation storage conditions When the preceding factors are controlled, minimal distortion can be expected in most instances of tissue excision [28–31]. Is tissue excision ever contraindicated? The ring technique of excision may be contraindicated under very few circumstances. These may include the following rare conditions and circumstances:

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Figure 14.17 Adding gel in unattached area (upper left) prior to excision, and ring excision (upper right, lower left, lower

right).

• • • •

The specimen is too difficult to access. Placement of the ring is impossible or impractical. The body part to be excised is too large. The resulting facial mutilation is a genuine aesthetic concern when the body is to be exposed. • Sample bitemarks are excised in a multiple bitemark case, and the perpetrator can be shown to be the same animal or person responsible for the other bites through photographic or other means. The most common reasons cited for failing to excise bitemarks on the deceased are the following: • Fear of potential lawsuits and/or family or political repercussions • Tissue shrinkage • No forensic dentist in the jurisdiction • Economic or financial issues • No previous bitemark case in the jurisdiction A bitemark is an important piece of evidence that may solve a crime. It should be treated as such and dealt with accordingly. Failure to take appropriate measures might be interpreted as obstruction of justice, professional negligence or malpractice, or incompetence.

14.5 Tissue Fixation Following excision and prior to fixation, photographs are taken when the transilluminated specimen reveals blood vessel engorgement or subcutaneous bleeding. Generally speaking, a specimen is fixed for at least 1 week depending on tissue thickness and size. Larger specimens needing additional support should float freely in the formaldehyde bath. The skin side of the specimen should be facing but not touching the bottom of the container. If specimen support is required, one is devised that will contact the ring rather than the tissue. Plastic autopsy containers have been cut transversely to form rings of various sizes as a means of additional support. The fixative used at the Laboratoire de Sciences Judiciaires et de Médecine Légale for bitemark specimens is 4% formaldehyde by volume (formalin is 40% formaldehyde in water; 10% formalin is equal to one part formalin in nine parts water) or a solution of 5 mL 40% formaldehyde, 5 mL 99.8% glacial acetic acid, and 90 mL 70% ethanol. The fixed specimen is removed from the bath of formaldehyde the following week to assess dimensional stability and adherence to the ring. It may be rephotographed before placement in a sealed plastic container (or bag) properly identified and stored in a refrigerated

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179

Figure 14.18 Dorion type V bitemark excision (upper left, upper right) and removal of excess muscle tissue with scissors rather than scalpel blade (lower left, lower right).

room (or refrigerator) in a secure area. The specimen should be rephotographed as necessary over time. In addition to tissue distortion resulting from excision of unsupported tissue, fixation itself can contribute to shrinkage. Distortion due to fixation of supported “ringed” tissue varies depending on the circumstance. Dorion reported a postfixation dimensional stability of <0.81% but >3.23% in an 11-year study [16]. This means that some of the specimens might have shrunk by as much as 3.23%, while others might have expanded by as much as 0.81%. The latter was the result of the tissue sagging in the central portion of the excised specimen. The specimens collected between 1981 and 1991 were of various sizes and shapes and included facial and head specimens, ear, thorax, arm, breast, pubis, thigh, and calf. They exhibited injury patterns from gunshot, knife, saw wounds, tire track injuries, and bitemarks. “Open” injuries from gunshot, knife, and saw wounds were different in shrinkage from the “closed” injuries of tire marks and bitemarks. As a whole, tissue shrinkage or expansion was minimized when the ring and cyanoacrylate technique was used. Brzozowski, Nawrocki, and Friedman [32] studied the comparison of dimensional stability of excised patterned injuries using various fixatives in a preliminary study; the following year, they focused on a comparative

study of materials and methods used for collecting, stabilizing, and preserving excised tissue [33]. In the preliminary study, the fixatives used were (1) neutral 10% buffered formalin, (2) modified Millonigs solution (formaldehyde 37%, distilled water, sodium phosphate monobasic, and sodium hydroxide), and (3) Prefer, a biodegradable fixative made of glyoxal, 20% ethanol, and a buffer (designed to replace formalin and zinc formalin as a fixative for histology and surgical pathology). Prefer is available from Anatech Ltd., 1020 Harts Lake Road, Battle Creek, MI, 49015 (800-ANATECH or 616-964-6450). A 2-inch square rubber stamp was divided into quarter-inch grades with a centrally located circle of 1-inch diameter. The pattern was stamped on postmortem porcine skin and then excised to the dermal layer with a PVC ring support, eight 3–0 silk black sutures, and cyanoacrylate glue. Samples were stored at room temperature; color photographs were taken before and after the excision and after fixation. Measurements were taken with a dial Vernier caliper at weekly intervals for the first 6 weeks and then at monthly intervals there after. Most tissue dimensional change occurs at the excisional stage, and more changes occur on curved excised tissue than on flat surfaces. All samples remained stable after fixation over a 12-month period.

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Figure 14.19â•‡ Distorted breast tissue (lower left, lower right) due to improper fixation technique. Note that the specimen was fixed with the impression material in place (upper right).

In an attempt to further minimize shrinkage, this author devised a variety of experiments. In one experiment, the skin was completely covered with impression material within the supporting ring prior to excision. Following fixation, the impression material was removed, only to find that the skin had completely wrinkled (FigureÂ€ 14.19). The wrinkling was probably due to an uneven fixation rate between the exposed fatty side and the protected skin side. Another aggravating problem involves the written information or identification markers placed on the supporting ring. Over time, the fixative has removed some of the written information. A variety of markers have been tested, including pencils, ink and indelible pens, and grease pencils. The most effective, long-lasting markings were made with a grease pencil.

14.6â•…Tissue Storage As previously mentioned, the fixed, supported, “ringed,” excised specimen is placed in an identified sealed plastic container such as Tupperware® or a sealed bag, preferably in a refrigerated unit or otherwise at room temperature. When the specimen is initially placed in a refrigerated unit, it has the effect of slowing the fixation rate to further minimize distortion. My 29 years of experience with postfixation storage favor permanent formaldehyde emersion of the excised ringed tissue in a

sealed plastic container such as Tupperware and placement in a refrigerated unit over bagging. Several methods of bagging have been experimented with. The bagged specimen has been in contact with or without gauze-impregnated formaldehyde and placed in a refrigerated unit or at room temperature. Leaving the postfixation specimen in a sealed plastic bag without impregnated formaldehyde gauze at room temperature leads to a combination of dehydration, shrinkage, and/ or detachment of the ring over time.

14.7â•…Transportation If displacement of the specimen becomes necessary, it should be transported in an additional container, preferably made out of Styrofoam. This latter material is strong and light, and it tolerates environmental and temperature changes.

14.8â•…Transillumination A technique whereby light is transmitted through an excised specimen, transillumination is paramount when skin indentations or abrasions are present and/or the identity of the causative agent is to be confirmed or is unknown. If the tissue specimen exhibits an inflammatory response (notably vascular engorgement or

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181

Figure 14.20â•‡ Illuminator/camera stand setup (left) and microscope/camera/fiber optic setup (right).

subcutaneous hemorrhage), it can readily be observed. The equipment setup for transillumination (Figure 14.20) includes the following: • X-ray film illuminator model 188 with variable rheostat made by S. & S. X-Ray Products, Inc. • A 5-mm-thick, round glass plate (15 cm in diameter) mounted on the x-ray film illuminator • A 75 W soft light bulb • Sheets of Styrofoam: 1.25-cm thick, perforated in the center to various diameters • Photographic equipment: standard camera, digital camera, video digital camera • A photographic mounting table • Side-mounted, variable-intensity photoflood lamps The additional benefits of conserving supported excised fixed tissue and the use of transillumination include: • The possibility of performing three-dimensional analysis of the patterned injury • To confirm the presence or absence of the inflammatory response (blood vessel engorgement and/or subcutaneous bleeding) without having to cut through the bitemark • The ability to analyze the relationship between the skin trauma (indentations, abrasions, etc.) and the inflammatory response • A means for an eventual direct or indirect three-dimensional comparison of the patterned injury to the causative agent (tire, knife, dentition, or other objects) Blood vessel engorgement and subcutaneous bleeding (hemorrhage) are an affirmation of antemortem

trauma. FigureÂ€ 14.21 exhibits bruising, a bitemark (within the oval in the upper left photo), and diaper indentations (marked by the black arrows) on the buttocks of the deceased child. Both the bruising and bitemark were hemorrhagic rather than blood vessel engorged. The photos (FigureÂ€ 14.21, right) depict the transÂ�illumÂ�iÂ�nated specimen, skin side and underside. FigureÂ€ 14.22 depicts over five superimposed bitemarks on the superior and lateral surface of a child’s thigh. The individual bitemarks appear more like bruises on the thigh, but are clearly identified as bitemarks in the transÂ�illumÂ�iÂ�nated tissue. FigureÂ€ 14.23 shows four indentations on a child’s stomach (photographed with a light almost parallel and at the level of the indentations) and the excised transÂ� illumÂ�iÂ�nated specimen. One could not have confirmed the presence of bitemarks solely on the basis of visual inspection of the stomach since there is little in the form of class and individual dental characteristics. The transÂ�illumÂ�iÂ�nated specimen clearly identifies the presence of two human bitemarks perpendicular to each other inflicted by a child dentition. Similar examples can be seen in FiguresÂ€22.23–22.25 and 22.29–22.31 in Chapter 22. FigureÂ€ 14.24 depicts a bitemark on the right thigh of a female homicide victim and the excised and transÂ� illumÂ�iÂ�nated specimen. FigureÂ€14.25 represents the bitemark on the arm of another female homicide victim and the direct comparison with the suspect dentition. FigureÂ€ 14.26 shows a bitemark on the pubis of a third female homicide victim, and FigureÂ€ 14.27 represents various views of a transÂ�illumÂ�iÂ�nated bitemark from the shoulder of a fourth female homicide victim. Caution should be exercised in preparing the excised specimen for transillumination because uneven tissue thickness and residual muscle may be interpreted as

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Figure 14.21â•‡ Diaper indentation (arrows) adjacent to bitemark (oval) and a bruise.

Figure 14.22â•‡ Bitemarks on child’s thigh, excised, and transÂ�illumÂ�iÂ�nated specimen.

hemorrhagic tissue. For the latter reason, photographing the dermal side of the tissue to demonstrate the presence or absence of hemorrhage is justified.

14.9â•…The Microscope The microscope setup (FigureÂ€ 14.20, right) can be used with or without the equipment used for transÂ� illumination: • A Leica MZ 75 microscope • A Volpi Intralux 6000–1 fiber optic lamp with variable rheostat • Side-mounted fiber optic lamps • Various adapters for the microscope • The equipment setup for transillumination

FigureÂ€14.28 illustrates a bitemark on the shoulder where both class and individual dental characteristics are observed. The arrows on the lower right photograph outline the barely perceptible contusions attributable to two lower teeth. Also note the tooth rotation adjacent to the barely perceptible contusions. FigureÂ€ 14.29 is a transÂ�illumÂ�iÂ�nated version of FigureÂ€ 14.28 showing the engorged blood vessels. FigureÂ€ 14.30 shows a magnified version with off-angle lighting. Note the parallel striations attributable to the clothing imprint. FigureÂ€ 14.31 depicts magnification of the epidermis with the same parallel striations left by the fabric weave (see Chapter 12). FigureÂ€ 14.29 depicts various magnifications of the bitemark produced by the perpetrator’s upper teeth. Note the creasing of skin immediately adjacent to the

Tissue Specimens

Figure 14.23 Four indentations on a child’s stomach and the excised transilluminated specimen.

Figure 14.24 Bitemark on an adult female thigh; excised (lower left) and transilluminated (lower right) specimens.

183

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 14.25 Excised bitemark on an arm, transilluminated, and the suspect dentition comparison.

incisors’ impact. The blood vessels are clearly engorged in the absence of subcutaneous bleeding. Three phenomena are occurring simultaneously: (1) compression of tissue by the upper and lower dental arches, (2) compression of the T-shirt into the bitemark, and (3) dragging of the upper dental arch. This is an unusual bitemark because the upper teeth are dragged. This could have resulted from victim movement rather than jaw closure. Normally, the lower teeth are dragged as a result of jaw closure. In other cases, both upper and lower teeth are dragged. Figures 14.29–14.31 required a combination of off-angle lighting from above and

transillumination from below the specimen to view the striations and the blood vessel engorgement. Blood vessel engorgement and subcutaneous bleeding and hemorrhage are vital tissue responses that can only occur if the recipient is alive at the time of trauma. Placing the bitemark perpetrator at the crime scene and being able to evaluate the amount of pain suffered by the recipient (e.g., perforated tissue) may be critical in a capital case. The presence of DNA does not indicate the timing of the incident, whether there was any clothing at the bite site, or the degree of force applied. The bitemark can. A total absence of the inflammatory response

Figure 14.26 Excised and transilluminated bitemark on the pubis.

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185

Figure 14.27â•‡ Different views of excised and transÂ�illumÂ�iÂ�nated bitemark on a shoulder.

(vascular engorgement or hemorrhage) coupled with tissue perforation attributable to the dentition would indicate that the bitemark was inflicted postmortem. FigureÂ€14.32 (upper left and upper right) illustrates imprints from the upper central incisors photographed normally and transÂ�illumÂ�iÂ�nated. Note the absence of subcutaneous hemorrhage and the barely perceptible blood vessel engorgement. The bottom photos view abrasions of unknown etiology on the nipple with neither blood vessel engorgement nor subcutaneous hemorrhage.

14.10â•…Histology Chapters 15 and 22 deal with histology. Suffice it to say that histology examination is the last of the invasive techniques. All of the previous noninvasive and invasive techniques should have been considered, if not implemented, prior to making histology sections. Once histology sections have been obtained, the excised specimen is rendered useless for bitemark analysis and comparison. FiguresÂ€ 14.33 and 14.34 illustrate various cuts (“A” through “E”) of indentations on the skin from which histological sections were made. The transÂ�illumÂ� iÂ�nated tissue (middle photo in FigureÂ€ 14.34) shows

neither blood vessel engorgement nor subcutaneous hemorrhage. It is important when cutting and subsequently reading histological sections that the areas adjacent to the tooth impact be examined for tissue changes, including blood vessel engorgement and subcutaneous hemorrhage. FigureÂ€14.34 (right) illustrates the necessity of examining areas denoted by X, Y, and Z. It should also be noted that, if areas A, B, C, D, and E represent sections through individual tooth imprints, the sections not represented adjacent to the tooth imprints could contain an inflammatory response as a result of the pinching action between the teeth; however, this would not be seen in the histology slide selection (see FigureÂ€14.35). Blood vessel engorgement and/or hemorrhagic patterns are associated with the following: • The incisal, occlusal, or lingual surfaces of teeth or a combination thereof (e.g., FigureÂ€14.29) • Tissue being pinched between teeth • A form of blunt trauma injury, adjacent to the site of impact, produced by individual teeth (e.g., FigureÂ€14.41, black arrows) • Crushing or compression of tissue between the dental arches (e.g., FigureÂ€14.27) • Negative pressure on the tissue (sucking)

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Figure 14.28 Close-up photographs of a bitemark on a shoulder.

14.11 Postfixation and Storage Figure 14.36 depicts two excised bitemarks and the transilluminated tissue. The freshly excised bitemark on an arm on the left and a breast excised 2 years earlier on the right clearly show different characteristics of the bitemark. The arm bitemark is basically a compression injury, whereas the breast specimen shows no hemorrhage and slight vascular engorgement in the indentations created by the central incisors. Figure 14.37 delineates four bitemarks on a male homicide victim’s elbow (left) and a bitemark on a female homicide victim’s shoulder (right). The hemorrhagic patterns on the elbow are attributed to the dentition, whereas the one on the shoulder is a compression injury resulting from the crushing and pulling of tissue between the dental arches as well as by the individual teeth. The shoulder specimen had been excised and fixed 6 years previously. The specimen had remained dimensionally stable since the autopsy despite its curvature. This can be verified through photographic, impression, and tissue comparison.

Figure 14.38 represents the same bitemark on the shoulder transilluminated 1 year later (7 years since excision). Figure 14.39 is a magnified version of the former showing the upper anterior teeth imprints (abrasions) and contusions. Figure 14.40 depicts a transilluminated bitemark photographed following the autopsy and then 3 years later. What has happened to the blood vessel engorgement and subcutaneous hemorrhage? It appears to have disappeared! This phenomenon was first reported at the American Academy of Forensic Sciences annual meeting in 1992 [16]. At the time, it was attributed to dilution of the red blood cells (RBCs) in the fixative or to RBC blanching. Whatever the reason might be, the importance of photographing the specimen upon excision and prior to fixation, particularly when blood vessel engorgement and subcutaneous hemorrhage exist, cannot be overemphasized. Figures 14.41 and 14.23 display two sets of indented bruises at right angles to each other superior to the navel on a child’s abdomen. At first glance, the suspicious marks lack both class and individual characteristics to

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187

Figure 14.29 Macroscopic and microscopic views of transilluminated bitemark and blood vessel engorgement.

classify them as bitemarks. Excision and transillumination of the tissue clearly demonstrate that the indentations represent sets of maxillary deciduous central incisors. In fact, two bitemarks are at right angles to each other. Blunt trauma injury, a well-known principle in forensic pathology, can be observed from the impact of the left central maxillary incisor. The hemorrhagic pattern surrounds the dental imprint from the left incisor. There is no corresponding blood vessel engorgement or hemorrhage associated with the adjacent incisor. These photographs are excellent examples of the potential of transillumination. Not only was transillumination essential to the diagnosis and confirmation

Figure 14.30 Microscopic view of transilluminated bitemark, blood vessel engorgement, and clothing imprint.

of the bitemarks, but it also clearly identified the perpetrator’s dentition as a child’s. Transillumination also serves to indicate where to excise the tissue for ulterior histological analysis. There are other advantages for the forensic dentist. This type of injury lends itself to the study of indentations and its association with the hemorrhage by “layering” in computer analysis. Lastly, Figure 14.42 demonstrates once again the need to photograph the excised tissue prior to fixation. The specimen has “lost” its hemorrhage over the years.

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Figure 14.31 Magnified view of a bitemark and clothing imprint.

Figure 14.32 Close-up of upper central imprints (upper left) on transilluminated breast tissue (upper right) and abrasions on areola/nipple (lower left, lower right).

Tissue Specimens

189

Figure 14.33â•‡ Five tissue cuts for the preparation of histology slides.

Figure 14.34â•‡ Thigh indentation (left), transÂ�illumÂ�iÂ�nated tissue (center), histology slide (right).

Tooth Imprint

Figure 14.35â•‡ Histology slide of a tooth imprint showing no vessel engorgement or hemorrhage.

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2 Years

Figure 14.36â•‡ Excised (upper left, upper right) and transÂ�illumÂ�iÂ�nated (lower left, lower right) bitemarks; arm (left) and

breast (right).

Tissue Specimens

191

6 Years

Figure 14.37â•‡ Excised (upper left, upper right) and transÂ�illumÂ�iÂ�nated (lower left, lower right) bitemarks on arm/elbow (left) and shoulder (right).

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition 7 Years

7 Years

7 Years

Figure 14.38 Fixed transilluminated bitemark from a shoulder 7 years after excision.

7 Years

7 Years

Figure 14.39 Close-up of transilluminated bitemark on the shoulder 7 years after excision.

3 Years

Figure 14.40 Transilluminated bitemark at autopsy (left) and 3 years after fixation (right).

Tissue Specimens

193

Figure 14.41â•‡ Suspicious marks on the abdomen and the transÂ�illumÂ�iÂ�nated specimen.

6 Years

Figure 14.42â•‡ TransÂ�illumÂ�iÂ�nated tissue 6 years after excision/fixation.

References 1. Sopher, I. M. 1993. In Medical legal investigation of death: Guidelines for the application of pathology to crime investigation, 3rd ed., ed. W. U. Spitz, 127. Springfield, IL: Charles C Thomas 2. State v. Adams, 481 A.2d 718, 727B28 (R.I. 1984). From Giannelli, P. C. 2008. Bite mark analysis. Case research paper series in legal studies. Working paper 08-06, Case Western Reserve School of Law, January 2008.

3. McNamee, A. H., and D. Sweet. 2003. Adherence of forensic odontologists to the ABFO guidelines for victim evidence collection. Journal of Forensic Sciences 48 (2): 382–385. 4. Dorion, R. B. J. 1981. Preliminary research on the preservation of traumatic injury patterns. Canadian Society of Forensic Science. Hamilton, Ontario, Aug. 1981.

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5. Dorion, R. B. J. 1982. Preliminary research on the preservation of traumatic injury patterns. American Academy of Forensic Sciences. Orlando, FL, Feb. 1982. 6. Dorion, R. B. J. 1984. Preservation of and transillumination in bite mark evidence. American Academy of Forensic Sciences. Anaheim, CA, Feb. 21–25, 1984. 7. Dorion, R. B. J. 1985. Preservation in bite mark evidence: Inanimate objects, foodstuff and human tissues. American Society of Forensic Odontology. Las Vegas, NV, Feb. 12, 1985. 8. Dorion, R. B. J. 1992. Lifting, preserving, storing and transporting skin: An eleven year study. American Academy of Forensic Sciences. New Orleans, LA, Feb. 17–22, 1992. 9. Dorion, R. B. J. 1993. Bite mark evidence. Identification and Laboratory Service Committee, Canadian Associa tion of Chiefs of Police. Montreal, Quebec, Apr. 14, 1993. 10. Dorion, R. B. J. 1997. Forensic odontology with special reference to bitemark evidence. Training course: Detection and recovery of human remains. Child Abduction and Serial Killer Unit, Evidence Recovery Team (ERT), Federal Bureau of Investigation (FBI), Quantico, VA, May 16, 1997. 11. Dorion, R. B. J. 1998. Les morsures [bitemarks]. 42eme Congres International de Medecine Legale et de Medecine Sociale de Langue Francaise, Lille, France, Sept. 11, 1998. 12. Dorion, R. B. J. 1999. Bitemarks in life and in death. Detection and recovery of human remains. Child Abduction and Serial Killer Unit, Evidence Recovery Team (ERT), Federal Bureau of Investigation (FBI), Quantico, VA, May 21, 1999. 13. Dorion, R. B. J. 1999. Bite mark recovery, preservation and forensic aspects of physical evidence. Council on Dental Practice, American Dental Association, Chicago, IL, March 26, 1999. 14. Dorion, R. B. J. 1999. Forensic dentistry overview and bitemark evidence. Regional Organized Crime Informa tion Center (R.O.C.I.C.), Lexington, KY, June 8, 1999. 15. Dorion, R. B. J. 2002. Les morsures: Evaluation clinique et protocole medico-legal. Hopital St. Justine, Montreal, Quebec, Feb. 28, 2002. 16. Dorion, R. B. J. 2004. The evolution of bitemark analysis in North America from the 20th to the 21st century. Tom Krauss’ memorial bitemark breakfast. American Academy of Forensic Sciences, Dallas, TX, Feb. 20, 2004. 17. Dorion, R. B. J., M. J. Perron, S. Laforte, and M. L. Nielsen. 2006. Bitemark research—Antemortem and postmortem bitemarks. American Academy of Forensic Sciences, Seattle, WA, Feb. 24, 2006. 18. Dorion, R. B. J. 2006. Factors affecting bitemark analysis. American Academy of Forensic Sciences, Seattle, WA, Feb. 24, 2006.

19. Dorion, R. B. J. 2007. Bitemark evidence. Shepard Board Law Center, Nova Southeastern University, Fort Lauderdale, FL, February 5, 2007. 20. Dorion, R. B. J., R. Beehler, T. Gromling, E. Meza, M. J. Perron, and S. Laforte. 2007. Bitemark research—Antemortem and postmortem bitemarks. Part 2. American Academy of Forensic Sciences, San Antonio, TX, Feb. 22, 2007. 21. Dorion, R. B. J. 2007. Bitemark analysis—Parts 1 and 2. Results. American Academy of Forensic Sciences, San Antonio, TX, Feb. 22, 2007. 22. Sweet, D. J., and R. B. Bastien. 1991. Use of an acrylonitrile-butadiene-styrene (ABS) plastic ring as a matrix in the recovery of bite mark evidence. Journal of Forensic Sciences 36 (5): 1565–1571. 23. Desranleau, S., and R. B. J. Dorion. In press. Bite marks: Physical properties of ring adhesion to skin—Phase 1. Journal of Forensic Sciences (March 2011). 24. Desranleau, S., and R. B. J. Dorion. 2010. Bite marks: Physical properties of ring adhesion to skin—Phase 2. American Academy of Forensic Sciences, Seattle, WA, Feb. 25, 2010. 25. Dorion, R. B. J. 1987. Transillumination in bite mark evidence. Journal of Forensic Sciences 32 (3): 690–697. 26. Rothwell, B. R., and A. V. Thien. 2001. Analysis of distortion in preserved bite mark skin. Journal of Forensic Sciences 46 (3): 573–576. 27. Dorion, R. B. J. 1999. Bite mark recovery, preservation and forensic aspects of physical evidence. Council on Dental Practice, ADA, Chicago, March 26, 1999. 28. Dorion, R. B. J. 1999. Bitemarks in life and in death. Detection and recovery of human remains. Child Abduction and Serial Killer Unit, Evidence Recovery Team (ERT), FBI, Quantico, VA, May 21, 1999. 29. Dorion, R. B. J. 1999. Forensic dentistry overview and bitemark evidence. Regional Organized Crime Information Center, Lexington, KY, June 8, 1999. 30. Dorion, R. B. J. 2001. Pitfalls in documenting and preserving bitemark evidence in pediatric deaths. American AAFS meeting, odontology section, Seattle, WA, 2001. 31. Dorion, R. B. J. 1992. Lifting, preserving, storing and transporting skin: An eleven-year study. AAFS meeting, odontology section, New Orleans, LA, Feb. 22, 1992. 32. Brzozowski, C. C., L. A. Nawrocki, and B. K. Friedman. 1999. A comparison of dimensional stability of excised patterned injuries using various fixatives: A preliminary study. AAFS meeting, odontology section, Feb. 1999. 33. Brzozowski, C. C., L. A. Nawrocki, and B. K. Friedman. 2000. A comparative study of materials and methods used for collecting, stabilizing, and preserving excised tissue. AAFS meeting, odontology section, Reno, NV, Feb. 26, 2000.

Histology and Timing of Injury Joseph H. Davis

15

Contents 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8

Did a Bite Occur and, If So, When? Timing of Bruises; Textbook Discordance Components of a Bitemark: Gross Appearance Abrasion Contusion/Bruise Laceration Aging of a Bruise Histopathology 15.8.1 Bruise 15.8.2 Abrasion 15.8.3 Literature Reviews 15.9 Histochemical/Biochemical: Literature Reviews 15.10 Literature Reviews: Critique 15.11 Aging of Bitemarks 15.12 The Value of Microscopic Study 15.13 The Report 15.14 Frequency of Bitemarks 15.15 Acute Bitemark Histopathology Is Unique 15.15.1 Artifacts 15.15.2 Interpretation 15.16 Healing Bitemark 15.17 Summary References

195 195 195 196 196 197 197 197 197 198 198 199 199 199 199 200 200 200 203 203 203 205 205

15.1â•…Did a Bite Occur and, If So, When? Bitemarks may occur on any surface of the body, including the tongue. They may be self-inflicted or inflicted by some other person or animal, including insects. Documentation and interpretation of a bitemark are complex and raise many questions. One such question may pertain to the temporal relation of the bite. Bitemark infliction may have occurred before, at the time of, or after death. In life, the patient may or may not be able to provide an accurate history of the event. It is incumbent upon investigators to gather all circumstantial data and attempt to verify the victim’s account.

15.2â•…Timing of Bruises; Textbook Discordance The healing response of tissue to injury applies only to the living. Conversely, bitemark injury occurring at or after death cannot produce this response. When healing

reaction is evident, it may assist in estimating the approximate time of injury. Many variables affect the precision of such estimates, especially those concerning the histopathology of bruising. Spitz discusses color changes over time and opines that microscopic examination is “considerably more reliable” than color changes [1]. DiMaio and DiMaio are of the opinion that histology “can be disposed of very rapidly” because consistent microscopic dating is impossible [2]. In neither text does there appear a detailed justification for the expressed opinions.

15.3â•…Components of a Bitemark: Gross Appearance The gross appearance of an acute bitemark reveals combinations of abrasions, contusions, sometimes laceration from breaking of skin, or intradermal capillary hemorrhages. Variables of site, of skin tissue thickness and health, of positional relationships, of interposed clothing, and of forces and dynamics all serve to alter

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the type and appearance of injury and reactions to the injuries. The microscopic findings add to this spectrum as noted later.

15.4 Abrasion The most prominent visible part of a bitemark pattern is abrasion. As commonly used by pathologists, the term abrasion refers to a loss of epidermis by scraping, exposing the dermis. However, what grossly appears as a scrape abrasion may be a compression of the epidermis when viewed microscopically. Hence, the terminology of a gross abrasion may allude to two different histological patterns—compression and scraping. A scrape abrasion may be superficial or deep. A deep abrasion may result in some damage to the capillaries in the dermis and result in leakage of erythrocytes and plasma, which create a crust during a healing process. Abrasions become firm as they dry. If moisture is present, an abrasion may not be visible. Figure 15.1 illustrates a female victim of manual strangulation who was found in a canal. Initial photographs of the damp skin of the throat revealed almost no evidence of abnormality. After the body was dried in the morgue refrigerator, the anterolateral neck region showed a mass of irregular abrasions. These were present earlier but were obscured by dampness. A body found in the rain or removed from water may have a bitemark that is overlooked at the scene but becomes visible at the morgue. The longer it dries, the more intense becomes

the contrast between abraded and nonabraded skin. This may also lead to confusion as to time relation to death.

15.5 Contusion/Bruise A contusion is an escape of blood from damaged capillaries into surrounding tissue. The contusion portion of a bitemark is variable depending on the forces applied and the nature of the tissue. Skin and subcutaneous tissue vary widely over the body of a person. The highly vascular loose tissue near the orbits on the face is different in bruising capability from the tight skin over the cartilage of the ear. A bruise may be superficial or deep. It may be a more or less obvious component of a visible bitemark. When blood escapes into soft tissue, it infiltrates and tends to follow lines of least resistance. Spread is affected by the amount of vascular injury, vital pressure in the arteries, and the nature of the tissue. Blood may track for long distances under unique circumstances. This author once incurred a minor tear of a deep gluteal muscle during a minor fall. No local surface coloration occurred, but blue discoloration of the toes became apparent 1 week later. One mitigating factor may have been the use of cardioprotective, low-dose maintenance aspirin. Can a body bruise after death? Certainly, if the forces applied are sufficient, blood is still fluid, and tissue is still loose enough to permit gravitational ooze of blood. A man bludgeoned his wife to death then shot himself in the temple with a handgun and was found

Figure 15.1 Strangled woman found in water. Undiscerned neck abrasions when the body was wet were revealed when it was dry.

Histology and Timing of Injury

in a sitting position, back to the wall. His face appeared normal. Two hours later the attendants stretched him out on the floor. A large, swollen black eye rapidly arose caused by gravitational oozing of blood into the orbit whose roof was fractured by the intracranial forces associated with the bullet. Similar prominent hemorrhages of the eyelids (mainly upper) can occur following postmortem removal of the eyes. These examples serve to indicate the variables of flow of blood during and after death. With a bitemark, the chances are that the amount of contusion is too small to yield dramatic variations. However, a dependent postmortem position assures additional after-death leakage of blood into the initial contusion.

15.6 Laceration A laceration is an actual break through the skin into deeper tissue. Some bitemarks include a laceration component that should be readily apparent. Avulsion, the tearing away of tissue, may occur with severe biting.

15.7 Aging of a Bruise Estimation of the duration of an injury may become an issue during legal proceedings. A defendant may admit to biting but may claim that it was consensual and occurred long before death. Careful documentation of physical characteristics of the wound, both macroscopic and microscopic, is indicated. The gross documentation includes photography with linear and color balance scales and proper lighting. Highlights from flash photography should be avoided. A careful documentation of the presence or absence of skin indentations should be made. In life, indentations of skin are ephemeral, lasting only several minutes. After death, without vital circulation in the tissues, they may persist until decomposition occurs. Artifacts of postmortem drying, insect activity (especially ants), or decomposition should be documented. Proper documentation has another value. A bite that leaves permanent scarring in the living victim may be just cause for a criminal charge of aggravated battery. Healing processes are one avenue to estimate the duration of an injury in a living person, but only if healing processes may be demonstrated. The absence of reaction may not be as valuable as the presence of a healing reaction. Reaction varies depending on the size and location of the wound as well as the physical status of the victim.

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In the living, color changes of contusion blood may indicate a time frame as the bruise changes from blue to yellow-green to yellow and finally fades from view. Bruises vary from case to case in their color change. Also, observers differ from one another in their ability to notice color changes. Ambient light affects color estimates. Observers do not see things in a uniform manner [3]. Cultural differences affect our perception of color. In the Kalahari Desert of Botswana, with an almost perpetual blue sky and rare rainfall, a single Setswana word exists for green and blue, whereas nearly a dozen exist for the shades of brown of cattle, which represent wealth (B. Davis, personal communication, 2003). An artist may note color shifts in photographs unnoticed by the nonartist. Human variables of perception may detract from the use of color change as a factor in time estimation. Bitemark bruises tend to be small and obscured by overlying abrasions. Color changes would be less prominent than in an uncomplicated larger bruise elsewhere. Textbook and literature reports concerned with color change over time are based on bruises much larger than a bitemark. The variables in color pattern determination make this an unreliable time indicator other than to offer broad estimates: fresh, not fresh, older, and healed. Such estimates must be proffered within the total context of the investigation.

15.8 Histopathology 15.8.1 Bruise During the late nineteenth and early twentieth centuries, the histological patterns of sterile wound healing were extensively studied. Most references concerned open wounds. Forensic pathology texts defined different types of wounds, including contusions (bruises). In his 1954 forensic pathology text, Moritz [4] offers descriptions of contusion components. If neutrophils have disintegrated, erythrocytes have lost their normal staining characteristics, and hemosiderin is present, the bruise is over 24 hours old, even in the absence of neutrophilic reaction. This author recalls his discomfiture as a fledgling forensic pathologist trying to determine the age of bruises using these limited reference points. In discussing the dating of injuries, Simpson [5] advises caution because “bruises are spreading, moving things.” He focuses on color change and affords little space to histological changes, which may represent a lack of support for histological studies in his jurisdiction. In a text devoted to microscopy in forensic

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pathology, Perper and Wecht [6] caution the precision of a bruise age estimate. They mention that early neutrophilic infiltration is histologically demonstrable about 4 hours after injury. Unfortunately, they omit reference to the report of Robertson and Mansfield [7], who published a key article (often overlooked) that demonstrates critical elements of tissue reaction. Extravasated blood, by itself, is bland. Their Figure 5 is a photomicrograph of the edge of a 5-day-old bruise that cannot be differentiated from a fresh bruise. No inflammatory healing reaction is evident. The overlooked point by prior and subsequent authors is that tissue crush, with cellular damage, creates the stimulus for neutrophilic reaction usually cited as evidence of time since injury infliction. A series of bruises inflicted at the same time may result in different cellular healing reactions depending on the presence or absence of crushed tissue cells. The tiny bitemark bruise may not present histological time changes of value. Absence of reaction may only reflect simple extravasation of blood. However, one should look carefully for disrupted or crushed tissue cells during the microscopic examination. These cells, with altered eosinophilic staining, may indicate that neutrophilic reaction might have been expected if life had continued after the injury. 15.8.2 Abrasion Bitemarks usually possess a surface abrasion component. Bruises may have associated surface abrasion trauma. Robertson and Hodge studied the histopathology of abrasions as an aid to determining the aging of associated bruises [8]. Their study materials were derived from automobile trauma where postinjury survival time was known. They divided their abrasions into two types: a tangential scrape with loss of epidermis and stratum papillaris and a right-angle blow by a hard object to the skin with crush of the epidermis. In either case, the healing changes are similar except that the right-angle blow results in a crushed, devitalized epidermis and stratum reticularis that become incorporated into the crust (scab). The results of the study indicate the following: • Scab formation consists of damaged epithelium and collagen, infiltrating neutrophils, coagulated blood, and fibrin. From the time aspect, neutrophils were clearly visible at 4–6 hours. Mention is made of an infrequent earlier appearance of neutrophils, but associated circumstances are not described. At about 8 hours, the zone of

neutrophils is a dense layer. At 12 hours, the zone of neutrophils is intense, with an outer surface layer of erythrocytes and fibrin or crushed epithelium if present in the first place. The neutrophilic zone has degenerating neutrophils and a deeper zone of abnormally stained collagen of the zona reticularis. Neutrophilic infiltration continues in the deeper zone at 48 hours; this is the total scab that will be shed. • Epithelial regeneration is visible at 48 hours, extending beneath the scab at the margins. • Subepidermal granulation, consisting of blood vessels and fibroblasts, occurs after the surface is epithelialized and is well formed during days 5–8. • After 12 days, a stage of regression of cellular activity occurs with a basement membrane beneath an atrophic epithelium. Weeks later, a few lymphocytes may yet be present about vessels. Robertson and Hodge mention that not all abrasions are deep and intense. Some are quite superficial, and epithelial growth may be demonstrated in 30 hours. In small abrasions, complete epithelialization has occurred in as little as 4 or 5 days. In blind studies, they found that predictions were most accurate when survival exceeded 4 days. The surface abrasions are most useful in assessing the age of the underlying bruise. Multiple abrasions on a single victim may run the gamut from faint and superficial to deep and intense, all from the same time period. The viewer of a bitemark should realize that Robertson and Hodge did not study bitemarks. Also, the degree of skin damage may vary from one part of a bitemark compared with another part of the same bite. 15.8.3 Literature Reviews Vanezis assessed and reviewed in great detail the interpretation of bruises at necropsy [9]. His is an omnibus review of all things with bruises and includes listings of all coagulopathies that affect bruising, considerations apart from aging, use of light sources and spectrophotometry in assessing color, aspects of healing of tissues, and histochemical and immunochemical assessments. His bibliography omits reference to the two works of Robertson but is otherwise wide ranging. A difficulty is separating the changes of healing of open wounds from those factors dealing strictly with bruises. In fact, most of the literature on timing of wounds is based on studies of open wounds, not bruises. That is why the Robertson papers are most valuable.

Histology and Timing of Injury

15.9 Histochemical/Biochemical: Literature Reviews As for histochemical studies and time-related changes, most of the methods would seem to have little application in daily forensic practice. The text by McMinn [10] is detailed up to its time (1969). The most current text with potential for forensic applications is by Raekallio and deals with aging of wounds by histochemical and biochemical methods [11]. It deals mainly with open wounds and is not very applicable to aging of bruises. From the forensic standpoint, Raekallio is proper in emphasizing of the importance of correlation of all data, including the death scene information. Determination of serotonin and histamine in neck tissues has been used to demonstrate that a victim whose body had been found hanging by the neck in order to simulate a suicide had been suffocated earlier. Hanging after death would be expected to result in the same concentrations of these substances at the hanging groove and control tissues elsewhere because the vital changes caused by injury would be absent. In a vital injury, the histamine and serotonin would rise, resulting in a variance between the injured tissue and control tissue nearby. This is a potentially valuable tool because conventional wisdom in forensic pathology, dating back a half century, was that it is not possible to tell the difference between the person suffocated and hanged later (homicide) and a victim of self-hanging (suicide). However, the applicability of histochemical and biochemical methods to bitemarks remains to be demonstrated in the future.

15.10 Literature Reviews: Critique Literature reviews fall into three broad categories. The first, which is quite rare, is that which is critical. The author has specific expertise in the field and is capable of rendering a critical analysis of all referenced literature citations. The second is the most common and involves a noncritical literature summary of bibliographic references. A third combines some personal experience in the methodologies being reviewed but summarizes other publications without critical analysis. Vanezis’s article is of the latter type [9]. He has experimented with instruments to measure and analyze light and color in the study of bruises and also reviewed a diverse array of literature covering the field of bruises in general. A two-page report on histological studies of bitemarks by Millington does not present full details or illustrations [15]. Literature review citations do not

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concern bitemarks and can be misleading as to histopathological characteristics of bitemarks.

15.11 Aging of Bitemarks Dailey and Bowers have specifically addressed the topic of bitemarks and their aging [12,13]. Theirs is a noncritical review containing summaries of some key references discussed before. They also mention three appellate court cases in which dental experts opined as to the age of a bitemark. The courts did not address the qualifications of the experts. The purpose of their review was the “hope of distilling the facts related to this controversial subject.” A certainty from their review is that estimating the age of a bruise from color is problematic.

15.12 The Value of Microscopic Study One factor that detracts from microscopic study is cost. Many large-volume death investigative agencies limit microscopic sections or frequently omit them, relying on formaldehyde tissue retention for a finite time in the event of a later need for microscopic slides. In Miami-Dade County, Florida, the Medical Examiner Department had a policy of taking routine sections from each autopsy—an average of 5.2 slides, some with more than one tissue sample—for each of the 2,213 autopsies performed during the fiscal year ending in 2002. Routine agency habits may affect the use of microscopic slides in bitemarks. Why bother to prepare microscopic sections upon a bitemark? Despite limitations of precision, microscopic evaluations of bitemarks are useful. Slides increase understanding of the complex processes of the bite. They furnish a permanent documentation of the characteristics of the bitemark. If omitted, allegations of insufficient investigation may arise in court. Full documentation is always proper. One may anticipate a defense allegation that the bitemark was consensual and not associated with the time of death. The forensic odontologist should orchestrate the slide preparation procedure. The characteristics of the bitemark must be documented first, before any alteration by removal of tissue blocks. When the odontological studies are complete, the pathologist may then prepare the slides and render an interpretation. The dissection procedure should be photographically documented so that the completed microscopic slide may be later matched with a specific site in the bitemark. Alternatively, a

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finite time range without consideration of all the circumstances may result in discrepancies harmful to the case investigation.

Superior A C Anterior

Posterior

D B Inferior

Figure 15.2â•‡ Plastic overlay bitemark tracing. Letters represent tissue block sites chosen for microscopic study.

clear plastic overlay may be prepared with indications of which microscopic section pertains to a specific portion of the bitemark pattern (FigureÂ€15.2). The pathologist should carefully detail the microscopic findings of surface and deeper features. A forensic pathologist is not expected to possess the skill of a competent forensic odontologist, but he or she should be able to recognize the bitemark and its significance. When the odontologist has decided that the specimen may be incised for transillumination and later microscopic study, the pathologist should work together with the odontologist. The first step for the pathologist is to document carefully the changes of skin and underlying tissue from the slide. False-positive neutrophil reactions may occur. During the initial bleeding, a neutrophil may accompany an erythrocyte. This is not time dependent. When blood settles in a test tube or after death in a vein within the body, it may separate, with the erythrocytes being covered by a thin layer of white cells—the buffy coat. Rarely, a microscopic section may include a small vein containing a buffy coat, a finding expected to mislead an unwary pathologist because healing changes may be subtle. Pathologist estimates of healing should be correlated with the gross appearance plus the circumstances.

15.13â•…The Report A careful description of details within each microscopic slide should be prepared. As to a specific time estimate, it is well to offer only evidence of vital reaction, meaning that the bitemark antedated the death. One should be conservative about the determination of lack of histopathological vital reaction in the bruises. One should not always expect to find clear patterns of healing, as demonstrated by Robertson and Hodge [8]. If additional information concerning specific times that may be addressed later should arise, initial expression of a

15.14â•…Frequency of Bitemarks Bitemarks constitute an infrequent component of a busy medical examiner or coroner practice. During 1992 through 2002, Miami-Dade County (population of 2.3 million) sustained 3,343 homicides. Only five homicide investigations involved a fresh bitemark as part of the criminal activity. Also within this group of homicides were noted three healed bitemarks, one in the healing process, and one pseudobitemark pattern secondary to abrasions from shattered window glass. A 12-year study from the Southern California area revealed a total of 92 bitemark examinations of all types [14]. Of these, 42 concerned deaths from Los Angeles County, an average of 3.5 per year as compared to only 0.4 per year in Miami-Dade County. Los Angeles County has five times as many homicides as Miami-Dade County (www.losangelesalmanac.com). Because histopathology studies of bitemarks are not frequent in any one institution, a registry where duplicates of slides and reports may be stored for study might be considered. Local odontologists could coordinate the submission to the registry. The American Board of Forensic Odontology (ABFO) or the American Society of Forensic Odontology (ASFO) might initiate such an endeavor. Only with a carefully analyzed large series may the full value of bitemark histopathology patterns and aging patterns be appreciated. A registry could also coordinate the use of histochemical and biochemical methodology in the examination of bitemarks.

15.15â•…Acute Bitemark Histopathology Is Unique Acute bitemark histopathological patterns present unique patterns not found in skin wounds from other forces. Outstanding are compression of epidermis and dermis in some zones. In marked contrast are very acute edematous changes of epidermis and dermis that may occur in the same bite. Microscopic slides from three acute cases were available. The bitemark paraffin blocks were recut and carefully stained with hematoxylin and eosin. They were studied with 10× and 40× objective lenses. Best detail was revealed with the 40× objective lenses. Representative fields were chosen for photomicrography.

Histology and Timing of Injury Case 1 A housewife was sexually assaulted and then died from multiple stab wounds. Death had occurred during the prior night hours. Two bite injuries were noted: a full bitemark on the right forearm and a partial bite arch on the dorsum of the right hand. They appeared fresh, as were the stab wounds. Two sections of the forearm bitemark were available. An abrupt transition of normal epidermis to a compressed form was noted. Cells were flattened with pyknotic nuclei (FigureÂ€15.3, left). The compression zone gave way to a scraped section with only bits of basal cells remaining until the end of the scraped area revealed an abrupt resumption of normal epidermis (FigureÂ€ 15.3, right). The dermis beneath the compressed and scraped epidermis was condensed, with fibroblast nuclei becoming pyknotic and elongated. The compressed dermis extended to the subdermal fat layer. No extravasated erythrocytes were noted in the superficial reticular dermis. The other forearm section was similar except for a much smaller zone of scraped epidermis. Within deep underlying fat, bleeding without neutrophilic reaction was present. The hand slide contained two portions of tissue. One had a scraped loss of a thick stratum corneum with residual compressed epidermis remaining in place. The edge of the remaining corneum remained but had separated from the epidermis (FigureÂ€ 15.4, left). The dermis was compressed and dense. No extravasated erythrocytes were seen in the superficial dermis. The other piece of tissue had a small zone of corneum loss with compression of the residual epidermis and the underlying dermis. Some hemorrhage was present at the junction with underlying

201 fat. In summary, this case had evidence of compression of skin with focal loss of the stratum corneum. Case 2 A man was found alongside a dirt road; he had been shot multiple times in the torso. Beneath a short-sleeved shirt, a fresh bitemark on his left posterior axillary fold was found. A plastic overlay sketch was prepared with indications of four microscopic sections: A, B, C, and D (FigureÂ€15.2). Patterns varied among the four skin sections: At one end of section A was a zone of dense compression of epidermis and dermis. Toward the other end of the section, small vacuoles of dermal papilla suggested slight edema. A scant amount of hemorrhage was present within deeper fat and some fat cells were ruptured. Section B had a zone of compression of epidermis and dermis at one margin. That gave way to a pronounced degree of intracellular vacuolization of epidermal cells and underlying edematous spaces of superficial reticular dermis. This pattern continued to the end of the tissue section. No deep hemorrhage was present. Section C had dense compression at one edge plus a small scraped area. Beyond this was a zone of edematous vacuolization of epidermis and dermis (FigureÂ€15.4, right). A few extravasated erythrocytes, some of which were fragmented, were noted within superficial reticular dermis. Section C also had a deep zone of hemorrhagic fat, with rupture and coalescence of fat cells (FigureÂ€15.5, left).

Figure 15.3â•‡ Compression of skin. Epidermal cells are flattened and pyknotic. Reticular dermis is dense with collagen fibers pressed together (left). Scraped zone with intact epidermis is on the right.

Figure 15.4â•‡ Stratum corneum scraped loose from compressed epidermis (left). Edema and compression of epidermis. Edema vacuoles in deeper epidermis and underlying reticular dermis (right).

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 15.5â•‡ Coalescence of fat plus adjacent hemorrhage. At this site, the hemorrhage was slight, but fat cells had

been ruptured (left). Focal edema of epidermis and dermal papilla. A few epidermal cells appear compressed; others did not (right). Section D had a pronounced degree of edema of epidermis and dermis, with some extravasated partially fragmented erythrocytes within papilla. At the opposite end of the section was compression of epidermis with a small scrape plus compression of thick dermis extending to underlying fat. In summary, Case 2 demonstrates compression distortion of full skin thickness plus edema of epidermis and superficial dermis elsewhere. Traumatically fragmented extravasated erythrocytes are consistent with the forces that crushed deep fat cells, resulting in coalescence of fat. Case 3 A man was shot in the head during a close physical altercation with two men. He had been wearing a shirt that was torn at the bite location. Below the right scapula was a bitemark with demonstrable indentations of the skin. Sections of skin and underlying tissue were excised at 3 o’clock, 6 o’clock, 9 o’clock, and 12 o’clock. Section 3 had no zone of dermal compression but did exhibit a zone of edema of epidermis and dermis. Intracellular vacuolization was confined to the deeper layers of the epidermis. Dermal edema vacuoles were more prominent in the papillary dermis and adjacent most superficial reticular dermis. Beneath the thick deeper dermal collagen was hemorrhage in the fat. Section 6 had a zone of compression of epidermis but it was less prominent in the underlying dermis. Elsewhere was a minimal zone of vacuolization of epidermal cells and edema of dermis; however, deep hemorrhage with fat droplets in the blood was present. Section 9 had scant edema of epidermis and papillary dermis (FigureÂ€15.5, right) and little deep fat hemorrhage. Section 12 had a continuous edema, end to end, with vacuolization of epidermis and dermis. Occasional tiny areas of epidermis were suggestive of some compressive pyknosis. In summary, this case demonstrates the variability of compressive force increasing the epidermal and dermal density, while within the same tissues edematous changes are evident. Deep fat hemorrhage is variable with evidence of rupture of deep fat cells.

It is clear from review of these three cases of fresh bitemarks that the complexity of bitemarks creates variable epidermal patterns of compression, scraping, and edematous intracellular vacuolization. The reticular dermis may likewise be densely compressed along with the epidermis or may exhibit edematous changes along with the epidermis. Deep fat hemorrhage may also include fat cell rupture and coalescence of fat into large globules. The compression changes are those of a crushing force yielding dense compressed tissues. The removal of circulation from the dense tissue results in no edema reaction. Elsewhere, without dense compression, very acute edematous reactions of epidermis and dermis have occurred. Edema may be considered an initial vital reaction of tissue. Most biting episodes are not documented with a specific time line. How many minutes took place before the reaction ceased cannot be determined. It is expected that the edematous reaction is a function of the applied disrupting forces plus the short postinjury survival time. What is quite evident is that histological patterns of fresh bitemarks are variable and cannot be unthinkingly extrapolated from the published literature, which is based on tissue reaction to other injury types. Bitemark histopathological characteristics are those of bitemarks, not automobile trauma. A thorough understanding of acute bitemark histopathology is essential before consideration of later healing phases. If any of these victims had survived for a matter of days, the histopathological patterns would have changed. Each edematous site would have reached its maximum edema. Bleeding would have reached its maximum. Some edematous epidermis may or may not become necrotic, depending upon the force damage. The compressed epidermis and dermis would have become necrotic depending upon the degree of irreversible damage. Those areas of irreversible damage would be expected to undergo the formation of a crust (scab) and heal according to the phases described by Robertson and Hodge [8]. However,

Histology and Timing of Injury

until a collection of bitemarks in various stages of healing has been properly documented, one may not forecast with exactitude what should be seen with light microscopy. 15.15.1â•…A rtifacts Initial study of microscopic slides on file was complicated by variants of staining technique and fading. Recutting and staining were a necessary part of the review. Portions of some tissue blocks had not been placed at right angles in the cassettes. This resulted in local areas of pseudothickening of epidermis, shifting of location of vacuolated cells, or even loss of portions of epidermis where interpretation of scraping loss was being sought. Lymphocyte infiltration as a reaction to the healing process is of concern. But what is the significance of lymphocyte infiltrates in the dermis beneath a bitemark? Not much if they were present before the bite occurred and are not a reaction to the bite. In two of the three cases, chance occurrence of lymphocyte foci was noted in the affected and nonaffected zones (FigureÂ€15.6). 15.15.2â•…Interpretation The complexities of a bitemark with multiple variations of pressure distortion result in nonuniform tissue patterns. In the preceding case examples, patterns of epidermis and dermis reaction vary. The not grossly apparent, yet microscopically demonstrable, patterns of pressure distortion of the epidermis and dermis along with dermal edema and overlying epidermal vacuoles was not described in the reviewed literature. Errors of

203

interpretation may occur when dissimilar and separate processes are considered as one. Because skin may contain preexisting small foci of dermal lymphocytes, their presence as indicators of inflammatory reaction to the bitemark must not be assumed in the absence of other corroboration. The pathologist should document precisely the variable changes in epidermis, dermis, and subdermis for each microscopic slide. Representative slides from different portions of the bitemark should be technically perfect. Interpretation should be performed with exquisite care and only in the light of the totality of the case investigation. During the review for this chapter, a “healing bitemark” opinion in the autopsy report for Case 3 was discovered to be erroneous. The bitemark not only was fresh but also had retained skin indentations.

15.16â•…Healing Bitemark The single true healing bitemark was not initially subject to histological study, although it had been excised and retained in formaldehyde solution. Case 4 was a 32-yearold white female killed by a gunshot wound to the head. A bitemark pattern “surrounded by a rim of purplish green-yellow contusion” was noted above the right breast (FigureÂ€ 15.7). After processing by the forensic odontologist, it was excised and preserved in formaldehyde (FigureÂ€15.8, left). The author retrieved it 8.5 years later and prepared five sections. Each was excised, placed atop the specimen, and photographed for orientation (FigureÂ€15.8, right). Each tissue block was processed and sections stained with H&E plus iron stains.

Figure 15.6â•‡ Perivascular lymphocytic infiltration. Dermal

infiltrates in nonaffected as well as affected zones, plus no other signs of healing, indicate prior presence of lymphocyte infiltrates.

Figure 15.7â•‡ Fresh bitemark described as a purplish, greenyellow contusion.

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 15.8â•‡ Excision of bitemark. Black is fingerprint powder (left). Preserved tissue specimen after excision of tissue blocks for microscopic study (right). Block E is atop the specimen.

Figure 15.9â•‡ Polymorphonuclear leucocyte infiltration in deeper dermis (left). Compressed epidermis with residual edema vacuoles (right).

Figure 15.10â•‡ Compressed epidermis containing a thin zone of necrotic epidermal cells. Black surface material is fingerprint powder (left). Compressed epidermis containing a thick zone of necrotic epidermal cells (right).

The residual of a fresh bitemark pattern with additional changes wrought by healing was expected. Crush defects, residual epidermal edema, and residual hemorrhage altered by the healing processes were noted. These varied within the five sections. Prominent was infiltration by polymorphonuclear leucocytes in looser tissue (FigureÂ€15.9, left) but not yet within the dense, compacted dermal collagen. Many of the polys had dense nuclei and dense pink cytoplasm; a few were undergoing disintegration. In the subcutaneous fat, erythrocytes had vari-

able decrease in staining. A few zones of fibrin exudate admixed with erythrocytes and polys were also noted in the subcutis. Epidermal changes were variable depending on the acute change that had been present, simple compression, or acute edema where residual effects remained (FigureÂ€15.9, right). Commonly noted beneath the stratum corneum were necrotic epidermal cell debris zones; some were thin (FigureÂ€ 15.10, left) and others thick (FigureÂ€15.10, right). Prussian blue stains for hemosiderin were negative.

Histology and Timing of Injury

The key concern with histological aging of a bitemark is whether it can be shown to antedate the time of death by the presence of unequivocal healing reaction, a life process. If a time frame is to be considered, it should be expressed in terms of the total evidence, including circumstances and odontology review. Findings within each mode of investigation must be compared with the others before rendering final opinions. As for opinions, they fall into two types: investigative and evidentiary. The former is knowingly based on incomplete data and is subject to change as newer data are received. Investigative opinion is used to assist others in their investigations. When the investigation is complete, a final assessment will result in evidentiary opinion, which may be expressed in court.

15.17 Summary Published texts and literature are not uniform in their applicability to the histopathological aging of bitemarks. Two popular forensic pathology textbooks lack concordance. Published literature on microscopic evidence of tissue healing for the most part is based upon open wounds not representative of the usual closed wound of a human bitemark. Although a literature review dealing specifically with bitemark histopathology exists, it is not based on bitemark histopathological study [12,13]. Bitemark histopathological findings are those of bitemarks, not other forms of injury upon which literature reviews are based. Bitemarks are not frequent. Local histopathological experience is limited. It is suggested that a national bitemark histopathological registry be created under the auspices of the ABFO or the ASFO. Members could coordinate the submission of case material when consulting with their local death investigative agencies.

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References 1. Spitz, W. U. 1993. Spitz & Fisher’s medicolegal investigation of death, 3rd ed., 202. Springfield. IL: Charles C Thomas. 2. DiMaio, V. J., and D. DiMaio. 2001. Forensic pathology, 2nd ed., 101. Boca Raton, FL: CRC Press. 3. Munang, L. A., P. A. Leonard, and J. Y. Q. Mok. 2002. Lack of agreement on color description between clinicians examining childhood bruising. Journal of Clinical Forensic Medicine 9 (4): 171–174. 4. Moritz, A. R. 1954. The pathology of trauma, 35. Philadelphia, PA: Lea & Febiger. 5. Simpson, K., ed. 1965. Taylor’s principles and practice of medical jurisprudence, 12th ed., vol. I, 188. Boston, MA: Little, Brown. 6. Perper, J. A., and C. H. Wecht. 1980. Microscopic diagnosis in forensic pathology. Springfield, IL: Charles C Thomas. 7. Robertson, I., and R. A. Mansfield. 1957. Antemortem and postmortem bruises of the skin, their differentiation. Journal of Forensic Medicine 4 (1): 2–10. 8. Robertson, I., and P. R. Hodge. 1972. Histopathology of healing abrasions. Forensic Science 1:17–25. 9. Vanezis, P. 2001. Interpreting bruises at necropsy. Journal of Clinical Pathology 54:348–355. 10. McMinn, R. M. H. 1969. Tissue repair. New York: Academic Press. 11. Raekallio, J. 1972. Determination of the age of wounds by histochemical and biochemical methods. Forensic Science 1:3–16. 12. Dailey, J. C., and C. M. Bowers. 1997. Aging of bitemarks: a literature review. Journal of Forensic Science 42 (5):792–795. 13. Dailey, J. C., and C. M. Bowers. 1995. Aging of bitemarks: a literature review. In Manual of forensic odontology, 3rd ed., ed. C. M. Bowers and G. Bell. Montpelier. VT: Printing Specialists. 14. Vale, G. H., and T. T. Noguchi. 1983. Anatomical distribution of human bite marks in a series of 67 cases. Journal of Forensic Sciences 28 (1): 61–69. 15. Millington, P. F. 1974. Histological studies of skin carrying bite marks. Journal of Forensic Science Society 14:239–240.

Bitemark Variables and Cases

V

16

Animal Bites Richard R. Souviron Contents 16.1 General Consideration 16.2 Aquatic Animal Bites 16.2.1 Nonfatal Aquatic Animal Bites 16.2.2 Fatal Aquatic Animal Bites 16.3 Carnivores 16.3.1 Nonfatal Animal Bites 16.3.2 Fatal Animal Bites 16.4 Animal Bite Protocol 16.5 Animal Bite Victim Evidence 16.6 Postmortem Animal Bites References

209 209 209 209 211 211 212 215 215 216 216

Thorough documentation and thoughtful interpretation are essential prerequisites if justice is to be done. J. H. Davis, MD

16.1â•…General Consideration Man and animal have interacted from prehistoric times. Man evolved from hunter to domesticator of animals. Domesticated animals provide food, companionship, labor, recreation, and entertainment for humans. Wild animals, on the other hand, view humans as threatening rivals or as a food source. With increasing interaction between humans and wild animals, death often results.

reef shark with a “bang stick.” The startled shark attacked the diver, who was then rescued by companions. A witnessed and videotaped barracuda bite resulted in a severe laceration of a diver’s index finger (Figure 16.1, right). The diver was feeding fish using a Ballyhoo (a needle-shaped bait fish) at a depth 80 feet. A 4-foot barracuda took the bait and index finger, leaving a Â�scalpel-like laceration. Nonfatal alligator bites on humans are on the increase in the southeastern United States. FigureÂ€16.2 (left) depicts an alligator bite received while the victim was attempting to wake the startled reptile by “stomping on its head.” 16.2.2â•…Fatal Aquatic Animal Bites There are basically four questions to be answered in a fatal aquatic attack:

16.2â•…Aquatic Animal Bites The oldest living aquatic predator, the shark, is master of its domain. Man’s increased presence (swimming, surfing, spear fishing, diving, etc.) has led to a corresponding increase in the number of shark attacks [1,2]. This remarkable predator and scavenger will attack and feed on just about anything, living or dead. 16.2.1â•…Nonfatal Aquatic Animal Bites In most nonfatal fish bites, victim and witness descriptions of the event and the pattern of injury are generally self-evident. FigureÂ€16.1 (left) depicts a healed shark bite on the lower leg. A spear fisherman aroused a Caribbean

What is the victim’s identity? Was the victim alive or dead when attacked? What was the cause of death? What was the manner of death? The pathologist should be able to determine whether the victim was alive or dead when attacked. The third and fourth questions are more difficult to answer. Did the swimmer die of a heart attack or drown? Was the homicide victim dumped and then scavenged? Were the sharks “frenzied” into killing as the victim was tossed overboard? Did the victim slip and then hit his head as he went overboard? Was he pushed?

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Figure 16.1â•‡ Healed bite from Caribbean reef shark (left). Lacerated index finger from a barracuda bite (right).

Figure 16.2â•‡ Nonfatal alligator bite (left). Leg avulsion shark bite (right).

The forensic dentist, although not involved in the cause or manner of death, might provide useful assistance in identifying the deceased, evaluating the patterned injuries, and identifying predator species and fish size. Other aquatic scavengers, including the crocodile and the alligator, have the same ability as does the shark in replacing lost teeth. Although the bitemark may only be secondary to the cause and manner of death, it is an important factor in assessing the total picture. The recognition, differentiation, and interpretation of fish bites are the shared responsibility of police investigators, coroner or medical examiner, pathologist, odontologist, and other experienced specialists such

as an ichthyologist and marine biologist (FiguresÂ€ 16.2, right, and 16.3, left). The great white shark is responsible for more fatal human attacks than any other shark species; the majority of these attacks occur off the shores of Australia. Florida’s bull, tiger, and hammerhead sharks are also bitemark contributors. FigureÂ€ 16.3 (right) illustrates a shark bite, most likely produced by a bull shark over 10 feet long. Circumstantial and eyewitness accounts determined the cause of death as shark attack (nondescript) and the manner as accidental. In another case, a scuba diver in South Florida disappeared in approximately 40 feet of water. His mutilated

Figure 16.3â•‡ Homicide victim scavenged by alligator (left). Fatal shark attack (right). Width of bitemark suggests an estimated shark length of over 10 feet.

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211

Figure 16.4â•‡ Shredded body from shark attack (left). Leg with tennis shoe found in tiger shark stomach (right).

In most cases of nonfatal animal bites, the victim simply describes the circumstance and identifies the animal, but there are exceptions. An 11-year-old white, mute, mentally retarded paraplegic with congenital spina bifida was left unattended and attacked by two German shepherd family pets with no previous history of violence [4]. The mother awoke to discover her daughter’s night clothing shredded, injuries including claw marks,

a bruised forearm, and avulsion of the daughter’s mons pubis (FigureÂ€16.6). The pattern of injuries was initially correctly interpreted by police and family as dog inflicted. Later, a child protection team nurse said in sworn deposition, “I don’t know what caused the injury but it was not dogs.” The statement seemed ludicrous in light of the circumstances of the lack of blood or tissue at the scene. No one had bothered evaluating the dogs, verifying the gastric or fecal content, or swabbing the victim for animal DNA. The court seized the child, and the mother was charged with felony child abuse. Subsequently the public defender acquired the assistance of three experienced forensic experts: a pathologist, an odontologist, and a veterinarian. One year of litigation resulted in the state dropping the charges against the mother [5]. The odontologist made dental casts of the sedated dogs employing vinyl-polysiloxane rather than alginate impression material. The latter does not produce an accurate impression of the anterior teeth. In addition, a series of models were poured from the vinylÂ�polysiloxane impression. The casts were poured in plastic (FigureÂ€16.7) rather than stone since the anterior teeth varied in size (relatively short and conical). Bubbles and dental and model fractures are more likely to occur with stone models.

Figure 16.5â•‡ Mountain lion dentition.

Figure 16.6â•‡ Tissue avulsion in nonfatal dog attack.

body was found 36 hours later with large shark bites and missing flesh [3]. The witnessed manner of death was accidental, but the cause was greatly debated: air embolism, exsanguination, drowning, etc. (FigureÂ€16.4, left). Another case involved retrieval of partial human remains found in a large tiger shark (FigureÂ€16.4, right). Unfortunately, the remains were never identified and it was not possible to determine the cause or manner of death.

16.3â•…Carnivores The carnivore’s dental anatomy and biting dynamics are important features in interpreting the species. Carnivore teeth vary greatly in size and arrangement (FigureÂ€16.5). 16.3.1â•…Nonfatal Animal Bites

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following incarceration rather than the dog bites contended by the defense pathologist and odontologist. There was no evaluation of the injuries at the time of arrest and the only evidence consisted of a few rulerless photographs. The defendant was tried for murder, and the state lost the case. The lesson is that forensic consultation should be the rule when pattern injuries are present. 16.3.2â•…Fatal Animal Bites Figure 16.7â•‡ Plastic cast reproducing dental detail without bubbles or fractures.

The tragedy of this case is that a nurse familiar with human-inflicted injuries rendered an opinion outside her field of expertise. The lack of familiarity with circumstance, the scene, and lack of consultation with experts familiar with dog-inflicted injuries led to a protracted miscarriage of justice. Since criminal or civil litigation might result from animal bites, it might be wise for inexperienced diagnosticians (emergency response personnel, nurses, physicians, pediatricians, dentists, and social workers) to consult rather than misdirect an investigation. In certain cases, consultation with veterinarians, wildlife officers, forensic pathologists, odontologists, and anthropologists might prevent, reduce, or correct misinterpretation of animal bites. A team approach provides the best opportunity for thorough documentation of circumstance, scene analysis, and proper photographic documentation. There were over 6000 dog bite cases recorded in Miami-Dade County in 1988. The following year the County placed a ban on owning pit bulls and by 2007 the number of dog bite cases had decreased to 992 per year. Similarly, in New York city there was a decrease in dog bite cases from 37,448 in 1971 to a low of 3776 in 2008. The decrease in the number of dog bite cases in both jurisdictions was attributed to the ban on pit bulls. With regard to the human bites, the Department of Health in New York reported 1591 cases, man on man, in 1985, and in Miami-Dade County there were a reported 897 cases in 2008. Interestingly, forensic odontologists are consulted far more often on human bites (man on man) than on dog bites [6–8]. Most nonfatal dog bite cases are resolved by personal testimony as the following example attests. A defendant charged in the homicide death of a dog owner claimed self-defense because the Doberman pinscher was ordered to attack. The defendant’s claim was that he accidentally shot the owner instead of the dog. The prosecution claimed that the defendant’s leg pattern injuries were self-inflicted fork wounds administered

The mountain lion and brown, black, and grizzly bears are the most dangerous wild animals to humans in North America. More mountain lion attacks have been reported in the previous 20 years than had been reported in the previous 100 years. The reason for this is that the mountain lion’s habitat is shrinking (FigureÂ€16.8). Grizzly bear and mountain lion bitemarks are similar in appearance, yet species specific. Paw prints, on the other hand, are quite characteristic [9,10]. Differentiating animals within a species is more difficult. Drs. Curtis Rollins (former medical examiner for Sacramento, California) and Duane Spencer (forensic dental consultant) were able to determine the gender (female) of a mountain lion that had attacked a human based on the bitemark arch dimension (FigureÂ€16.9, left). A professional hunter was

Figure 16.8â•‡ Victim of mountain lion attack in California. (Photo courtesy of Drs. Curtis Rollins and Duane Spencer.)

Animal Bites

213

Figure 16.9â•‡ Mountain lion bitemark (left). Mountain lion dental cast over bitemark (right). (Right photo courtesy of Drs. Curtis Rollins and Duane Spencer.)

Figure 16.10â•‡ Bengal tiger tooth embedded in jaw, tiger tooth, and endodontic treatment.

used to locate the animal, and the teeth matched the bitemarks (FigureÂ€16.9, right). The victim’s DNA was recovered from the mountain lion’s claws [11–13]. Fatal bites from zoo animals are usually the result of not following safety procedures. An unsecured gate led to the tragic death of a Florida zoo handler attacked by a white Bengal tiger. The bitemark included an embedded lower canine in the victim’s cheek (FigureÂ€16.10). The tiger was not destroyed and required endodontic treatment. The forensic dentist does not normally visit the crime scene, nor is he or she always initially privy to the details of an investigation. Crime scene investigators, on the other hand, are trained at processing crime scenes. Photography, videography, and topographic drawings are used to record the event. The odontologist should familiarize himself or herself with these findings

and the circumstances of the event—preferably before the autopsy, but certainly before rendering an opinion regarding the origin of the pattern injury [14]. It is the role of the medical examiner, pathologist, or coroner to diagnose and consult with the forensic dentist when patterned injuries consistent with bitemarks of human or animal origin are suspected. The forensic dentist will examine, record, document (FigureÂ€ 16.11, left), and preserve the pattern injury as needed. Black-and-white, color, or alternate light photographs, and video documentation are but a few of the means of documenting the condition. In the presence of multiple animal bites, it is difficult if not impossible to apply a bitemark protocol that would record each and every wound individually, take impressions, and remove all of the affected tissue. Selective tissue impression,

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Figure 16.11â•‡ Placement of ABFO no. 2 scale for photography (left). A dog bite (right).

Figure 16.12â•‡ Direct dental comparison (left). Facial avulsion (right).

Figure 16.13â•‡ Tiger canine laceration (left). Leg lacerations in a fatal pit bull attack (right).

excision, and preservation (FigureÂ€16.11, right) and direct tissue comparison may be more appropriate under certain circumstances (FigureÂ€16.12, left). Claw marks, drag marks, and tissue avulsion present specific interpretation issues (FigureÂ€16.12, right). Canines, premolars, and molars in larger dogs and cats can produce a pattern injury that may be misinterpreted as stab wounds by the unsuspecting or inexperienced (FigureÂ€ 16.13). Careful macroscopic and microscopic examination will differentiate stab wounds from animal bites.

The American Veterinary Medical Association (AVMA), the American Society of Plastic Surgeons (ASPS), and the Centers for Disease Control and PrevenÂ� tion (CDC) sponsor National Dog Bite Prevention Week in May. A 20-year review of fatal dog attacks in the United States (238 cases) revealed that about half involved pit bulls or rottweilers. In Miami-Dade County, Florida, it is illegal to own a pit bull and owning one is punishable by a fine of $500.00. In spite of the fine, some dogs are raised for combat while others are illegally kept.

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215

16.4â•…A nimal Bite Protocol This suggested protocol is valid for all land animals and is particularly applicable to domesticated dogs.

Figure 16.14â•‡ Fatal pit bull attack.

A recent case from central Florida involved a deceased 5-year-old white girl found in a backyard adjoining a lake. Family members claimed the child, while playing with three family pit bulls, was attacked by an alligator. Florida Game, Fish and Wildlife and the Sheriff’s Department personnel opined that the bites resulted from dogs, not an alligator. Scene photographs were critical in assessing the situation because the child’s toys and torn, bitten clothing were scattered. The forensic dentist arrived at the same conclusion: dog bites, not alligator bites (FigureÂ€16.14). The alligator’s (FigureÂ€ 16.15, left) primary food source is fish, small animals, and the occasional child. Death usually results from drowning, and the victim is eaten later. The example in FigureÂ€16.15 (right) illustrates a case of a child seized by an alligator. Several hours later the captured gator still had the child in its mouth.

1. Examine the animal for blood and visible transfer of evidence from the victim. 2. Gather the victim’s DNA from the animal’s claws. 3. Immediately take the animal to a veterinarian to induce vomiting. 4. Strain the contents and preserve tissue and cloth fragments or other foreign bodies found in the vomitus for comparison with victim and clothing. 5. Quarantine the animal for collection of feces and compare the evidence of hair, tissue, bone, and clothing. 6. Take dental impressions of the suspect animal; create and pour models in plastic. 7. Do a rabies test on both victim and animal since the animal’s owner may later claim that the animal, unknown to him or her, may have been rabid.

16.5â•…A nimal Bite Victim Evidence 1. Swab for animal saliva and DNA left on the victim. 2. Retain the victim’s clothing for DNA analysis. 3. Analyze the clothing for teeth marks. 4. Follow ABFO guidelines for preservation of bitemark evidence.

Figure 16.15â•‡ Alligator teeth (left). Alligator bitemarks with embedded teeth (right).

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Figure 16.16â•‡ Opossum feeding on homicide victim (left). Insect activity mimicking single-arch bitemark (right).

16.6â•…Postmortem Animal Bites Identification and interpretation of bitemarks on the deceased, especially the decomposing, are difficult [15]. Rodent, cat, small dog, or wild animal bites may be difficult to differentiate yet contribute to the problem. Scene evaluation and circumstance are important factors in pattern injury interpretation, particularly if the body was found outdoors or in the presence of animals, insects, etc. For example, pattern injuries on a homicide victim found in a wooded area were attributed to witnessed opossum bites (FigureÂ€ 16.16, left). Crime scene personnel can best evaluate ant and roach attribution (FigureÂ€16.16, right). Alan R. Moritz, M.D., has said, “If evidence has been properly gathered and preserved, a mistake in interpretation may always be corrected. If the facts required for a correct interpretation are not preserved, the mistake is irreversible.”

References 1. Matthews, R. 1995. The deep—Shark bites, nightmares of nature. The book of the BBC, TV Series. 2. Gilbert, P. W. 1963. Sharks and survival, 510–567. Boston, MA: D. C. Health. 3. Davis, J. H. 1993. Injuries due to animals. In The pathology of trauma, 2nd ed., ed. J. K. Mason. Hodder Stoughton, Ltd., dist. by Little, Brown & Co. Boston, MA. 4. Foote, T. 1992. That is not a bad dog—That’s a splendid dog. Washington, D.C.: Smithsonian.

5. Reigger, M. H., and J. Guntzelman. 1990. Prevention and amelioration of stress and consequences of interaction between children and dogs. Journal of American Veterinary Association 196:1781–1785. 6. Lauridson, J. R., and L. Myers. 1993. Evaluation of fatal dog bites: The view of the medical examiner and animal behaviorist. Journal of Forensic Sciences 38 (3): 726–731. 7. Borchelt, P., R. Lockwood, A. Beck, and V. Voith. 1983. Attacks by packs of dogs involving predation on human beings. Public Health Report 98:57–66. 8. Sacks, J., R. W. Sattin, and S. E. Bonzo. 1989. Dog bite related fatalities from 1979 through 1988. Journal of American Medical Association 262 (11): 1489–1492. 9. Tough, S. C., and J. C. Butt. 1992. A review of fatal bear maulings in Alberta. American Journal of Forensic Medicine and Pathology 14:22–27. 10. Matthews, R. 1995. Maneaters—Bears, nightmares of nature. The book of the BBC TV series. 11. Rollins, C. E., and D. E. Spencer. 1995. A fatality and the American mountain lion: Bite mark analysis and profile of the offending lion. Journal of Forensic Sciences 40 (3): 486–489. 12. Cohle, S. D., C. W. Harlan, and G. Harlan. 1990. Fatal big cat attacks. American Journal of Forensic Medicine and Pathology II (3): 208–212. 13. Matthews, R. 1995. Maneaters—Large cats, nightmares of nature. The book of the BBC TV series. 14. Nordby, J. J. 1992. Can we believe what we see, if we see what we believe? Expert disagreement. Journal of Forensic Sciences 37 (4): 1115–1124. 15. Clark, M. A., G. E. Sandusky, D. A. Hawley, P. M. Pless, and L. R. Tate. 1991. Fatal and near-fatal animal bite injuries. Journal of Forensic Sciences 36 (4): 1256–1261.

17

Carnivore Bitemarks Robert B. J. Dorion Contents 17.1 Introduction 17.2 The Carnivore 17.2.1 The Mountain Lion 17.2.2 The Bear 17.2.3 The Canine 17.2.4 Nonfatal Canine Attack 17.2.5 Fatal Canine Attack 17.2.6 Deathbed Bitemarks 17.3 Forensic Nightmare: Misdiagnosis 17.3.1 Pattern Distribution on the Arm 17.3.2 Wound Patterning on the Neck 17.3.3 Direction of Wound Patterning on the Neck 17.3.4 Bitemarks on the Back 17.3.5 Clothing 17.3.6 The Humerus 17.3.7 The Mandible 17.3.8 The Skull and Cervical Vertebra: Holes and Bitemarks 17.3.9 “Blood Wiping” on the Skull 17.3.10 Impressions and X-rays 17.3.11 The Avulsed Scalp 17.3.12 Size of Defect on the Skull versus Avulsed Scalp 17.3.13 Size and Location of Perforations on the Scalp 17.3.14 Tissue Vitality and Transillumination 17.3.15 Failures of the First Autopsy 17.3.16 Failures of the First Autopsy Report 17.3.17 Forensic Lessons to Be Learned References

217 217 218 218 218 223 224 226 228 230 230 230 232 232 233 233 233 235 235 235 236 237 237 238 239 239 240

17.1â•…Introduction

17.2â•…The Carnivore

Insect bites cause many more deaths in the world than animal bites. According to the World Health Organization [1], an estimated 50 million dengue infections occur worldwide every year. Dengue hemorrhagic fever (DHF), the more serious form of the viral disease transmitted by the bite of the infected mosquito, Aedes aegypti, can cause bleeding and shock, leading to death. In 2007 in the Americas alone, there were 890,000 reported cases of dengue, of which 26,000 cases were DHF. Malaria, on the other hand, is caused by a microscopic parasite (protozoa) transmitted from person to person by the female anopheline mosquito. Over one million deaths each year result from 300 million acute cases of malaria.

In biological classification, rank is the relative position in a taxonomic hierarchy that is divided into eight major categories: domain, kingdom, phylum, class, order, family, genus, and species. The mountain lion, for example, belongs to the kingdom Animalia, phylum Chordata, class Mammalia, and order Carnivora, which incorporate cats, canines, bears, badgers, weasels, skunks, and others; family Felidae, including mountain lions, bobcats, Canadian lynx, jaguars, tigers, lions, margays, ocelots, leopards, cheetahs, and domestic cats; genus Puma; and species (Puma concolor) mountain lion. The carnivore dental formula is I 3/3: C 1 /1: PM 4/4: M 3/3 = 44. Murmann et al. present an interesting article on comparing animal jaws and bitemark patterns [2].

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17.2.1â•…The Mountain Lion The reported attack rate of mountain lions in the United States and Canada is six attacks with just under one death per year. The number has been constant since at least 1991 [3]. See the previous chapter and the article by Rollins and Spencer for additional information on mountain lions [4] (see FiguresÂ€17.1–17.3). 17.2.2â•…The Bear Grizzly (brown) and black bears in the past century killed 133 people in North America. There is a partial list of type, place, and circumstance of fatal bear attacks [5] (see FiguresÂ€ 17.4–17.6). An adolescent was with a group of campers in a provincial park. A black bear entered a tent and attacked and fatally mauled the boy, causing severe injuries to the chest, shoulder, and neck (see FigureÂ€17.7). A 23-year-old white female was jogging on a trail through a forest at the end of summer. She had been warned not to jog alone because of the numerous sightings of bears with cubs. Despite the warnings, she departed alone listening to a Walkman. She was found the following day mauled to death. What is unusual about the bitemark on the hip is that it is parallel rather than perpendicular to it (FigureÂ€ 17.8 lower left, lower

right). Although any scenario is possible, the bitemark suggests that the jogger was in motion rather than stationary and attacked from the right side rather than from the front or the back. The upper and lower left canines are penetrating while there is slippage but identifiable teeth from the upper and lower right. There are multiple penetrating neck wounds inflicted by the canine teeth, with vertebral crushing and separation resulting in death (FigureÂ€17.8, upper left). 17.2.3â•…The Canine The gray wolf (Canis lupus) is the largest wild member of the Canidae family. DNA sequencing studies confirm that the gray wolf shares a common ancestry with the domestic dog (Canis lupus familiaris). Human death by wolf mauling is an extremely rare occurrence. In 50 years there has only been one suspected occurrence and that was recent [6] (see FigureÂ€17.9). In 1994, 4.7 million persons sustained dog bites in the United States; approximately 800,000 of them required medical attention. Dog bites killed 340 people in the United States from 1979 to 1996. Most of the fatalities involved children 14 and younger; rottweilers and pit bulls accounted for more than half of those deaths, according to the Centers for Disease Control

Mountain Lion (Puma concolor) I 3/3, C 1/1, P 3/2, M 1/1 = 30 2.1–4.5 cm

1.0–4.0 cm

Figure 17.1â•‡ Mountain lion dentition (FMNH 51472). (Courtesy of the Field Museum of Natural History, Chicago, Illinois, and Dr. Denise C. Murmann.) Domestic Cat (Felis silvestris) I 3/3, C 1/1, P 2/2, M 1/1 = 28 0.7–2.2 cm

0.4–1.8 cm

Figure 17.2â•‡ Domestic cat dentition (FMNH 60353). (Courtesy of the Field Museum of Natural History, Chicago, Illinois, and Dr. Denise C. Murmann.)

Carnivore Bitemarks

219 Comparision of Human to Carnivore Bite Mark Patterns

Black Bear

Human

Gray Wolf

Figure 17.3â•‡ Comparison of human to carnivore bite pattern. (Courtesy of Dr. Denise C. Murmann.)

Grizzly Bear (Ursus arctos) I 3/3, C 1/1, P 4/4, M 2/3 = 42

3.4–9.6 cm 1.5–9.1 cm

Figure 17.4â•‡ Grizzly bear dentition (FMNH 21859). (Courtesy of the Field Museum of Natural History, Chicago, Illinois, and Dr. Denise C. Murmann.)

Black Bear (Ursus americanus) I 3/3, C 1/1, P 4/4, M 2/3 = 42

2.0–6.0 cm 1.1–5.2 cm

Figure 17.5â•‡ Black bear dentition (FMNH 72895). (Courtesy of the Field Museum of Natural History, Chicago, Illinois, and Dr. Denise C. Murmann.)

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Wolverines and Bears

Dog Family

Lynx

Wolverine

Coyote

Mountain Lion

Black Bear

Gray Wolf

Figure 17.6â•‡ Comparison of six animal bite patterns. (Courtesy of Dr. Denise C. Murmann.)

Figure 17.7â•‡ Bitemarks from a fatal black bear attack on a white male adolescent.

and Prevention [7]. In the United States, from 2004 to 2009 there were 172 fatal dog attacks, which averages to 28 per year [8]. Breeds causing deaths are, in descending order: pit bull terrier (104), rottweiler (58), wolf hybrid (18), husky (13), German shepherd (7), German shepherd mix (6), bull mastiff (Presa Canario; 6), chow (6), and various other breeds for a total of 264 dog attack deaths in the United States and Canada from September 1982 to November 13, 2006 [9]. This study’s results vary slightly from another in the Journal of the Veterinary Medicine Association [10] (see FigureÂ€17.10). An attacking animal will attempt to immobilize its subject by striking at the limbs. Once the subject has been

“brought down,” the animal will attack any body part to strike the throat, neck, or skull. If the attack persists, death will ultimately result from asphyxia, exsanguination, broken neck, or fractured skull or its complications, or a combination thereof. Dog bites will vary in size and pattern of injury depending on the animal’s size and the surface bitten. The bitemark will differ in appearance on the skull (FiguresÂ€ 17.15–17.17 and 17.29–17.36) from the arm (FiguresÂ€ 17.19, 17.20, and 17.23) to the leg (FiguresÂ€ 17.11, 17.19, and 17.21), back (FigureÂ€ 17.26), lip (FigureÂ€17.22), or neck (FiguresÂ€17.17, 17.18, 17.24, 17.25, 17.34, and 17.36).

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221

Figure 17.8â•‡ Neck and head wounds from two fatal black bear attacks (upper left, upper right). Penetrating wounds on the right hip from a black bear bite.

Gray Wolf (Canis lupus) I 3/3, C 1/1, P 4/4, M 2/3 = 42

2.3–5.1 cm 1.1–4.5 cm

Figure 17.9â•‡ Gray wolf dentition (FMNH 160108). (Courtesy of the Field Museum of Natural History, Chicago, Illinois, and Dr. Denise C. Murmann.)

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition Domestic Dog (Canis familiaris) I 3/3, C 1/1, P 4/4, M 2/3 = 42

1.3–4.8 cm 0.6–4.9 cm

Figure 17.10â•‡ Domestic dog dentition (shepherd/malamute mix; FMNH 146006). (Courtesy of the Field Museum of Natural History, Chicago, Illinois, and Dr. Denise C. Murmann.)

Figure 17.11â•‡ Contusion, laceration, and puncture marks from a dog bitemark on the leg.

The St. Bernard is generally not an aggressive breed, although it has bitten victims on occasion and in rare instances has mauled a person to death [11]. FigureÂ€17.12 depicts a St. Bernard dentition and FigureÂ€17.13 that of a retriever.

Figure 17.12â•‡ Dentition of a St. Bernard.

The American pit bull terrier is the most fearsome of canines because of its tenacity in holding on to its victim. The canine dentition in occlusion has anterior teeth interlocking; the lower canines are anterior to the upper counterpart and the premolars are not in contact. While the human dentition has six anterior teeth, the dog has eight. The size, shape, and horizontal height of the anterior teeth vary. The third tooth from the midline is usually longer than the first two. The shape of the first three teeth is not necessarily conical, but rather depends on genetics, wear, and occlusion. By far the largest and longest tooth is the canine. Of any puncture mark attributed to a dog’s dentition, the canine would be the most penetrating. Tooth alignment along the dental arch from canine to the last molar does not follow a straight path. If a dog grabs hold of a person’s limb with its premolars, the dentition penetrates unevenly as a result of different tooth size, different horizontal heights of the teeth, and the uneven anteroposterior alignment of teeth. The bites attributed to the maxillary teeth on one side of the limb would be different in appearance from those attributed to the mandibular teeth on the opposite side of the limb. Coupling this with the dog’s shaking movement causes a

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Figure 17.13â•‡ Retriever dentition.

Figure 17.14â•‡ Lateral view of the pit bull dentition.

ripping and shredding of skin and muscle tissue. Trauma resulting from a dog bitemark probably differs more in appearance than human-inflicted bitemarks because of these variations. The pit bull has by far the most powerful jaws among dogs: pit bull—1350 lb/in.2; rottweiler—750 lb/in.2; German shepherd—575 lb/in.2 (see FigureÂ€17.14). 17.2.4â•…Nonfatal Canine Attack A mentally challenged 13-year-old female was found at home in a state of shock, hemorrhaging from partial scalping. The parents claimed to have found the child in this condition upon returning from a shopping trip. Authorities were concerned that the parents or an intruder may have beaten or stabbed the adolescent.

Fortunately, the adolescent did not have neurological damage, and the medical emergency was restricted to numerous scalp sutures. FigureÂ€17.15 depicts a series of photographs taken from different angles. Note the lower canine slippage (upper right, center left, lower right), followed by skull contact of all lower anterior teeth. Maximum contact of the dog’s eight lower anterior teeth with the skull was achieved and formed the crescent shape. The upper canines engaged the skull at the top of the skull (purple arrow). As the animal closed its jaw, two shorter upper anterior teeth grazed the skull (red arrows), producing parallel marks to the upper canines. Note the absence of a crescent-shaped pattern on top of the skull. As the lower anterior teeth penetrated the scalp, it separated scalp from skull, producing a loose flap of

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Figure 17.15â•‡ Bitemark inflicted by a Great Dane.

tissue extending to the yellow arrows. The upper and lower canines approximated one another in jaw closure at these points. The anterior view depicts the wider track produced by the upper canines. The dog’s posterior teeth are not involved in any part of this bitemark. The family pet was a Great Dane. 17.2.5â•…Fatal Canine Attack Fatal canine attacks have been reported by numerous authors [12–24]. The following case highlights facial wounds, partial scalping, and a fractured skull from a fatal

husky attack (FigureÂ€17.16). The dog’s anterior dental alignment is represented by the green arrows in FigureÂ€17.16. A second bite produced a flap of tissue held by the hemostat. The canine tooth penetrated and fractured the skull in a third bite (blue arrow). The black and white arrows represent canine tracks from the husky’s opposite jaw. Note that the track depicted by the black arrow extends below the angle of the mandible through the right cheek to the inferior medial aspect of the right eye. In an unrelated case, a 2-year-old white male was found dead in an enclosure that held a husky. Bitemarks were found on the head, neck, and trunk (FigureÂ€17.17).

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225

Figure 17.16â•‡ Fatal husky attack: facial, scalp, and skull trauma.

It is interesting to compare the scalp injuries to the previous case. They are different in appearance as a result of the particular dog’s dentition, the animal’s head and paw position and movement, and the victim’s head position and movement. There is no clear indication of paired incised wounds attributable to the canine teeth from the same dental arch. Moreover, there is little indication of an alignment of contusions forming a semicrescent shape that would indicate the dog’s eight anterior teeth. The underlying subcutaneous scalp, neck, and thoracic injuries are more revealing than the corresponding external injuries. The cause of death was attributed to internal and external hemorrhage including perforation of the left jugular vein secondary to multiple dog bites. Two brothers had been left at the school bus stop when they noticed three fenced rottweilers that were agitated and attempting to break out of the enclosure. The dogs succeeded and, as they approached, the boys climbed a tree to escape. The dogs disappeared over a knoll as one of the boys descended the tree. The dogs immediately reappeared, encircled the boy, attacked, dragged him into a ravine, and mauled him to death

while his brother witnessed the attack. All three dogs were later destroyed. The injuries suffered were quite extensive and the cause of death was a severed spinal cord in conjunction with a torn carotid sheath (including the carotid artery, jugular vein, and vagus nerve). During the investigation, the adult dogs (specifically, the male “alpha dog”) were found to have incomplete Schutzhund training. With this information, the initial charge of involuntary manslaughter was changed to unintentional second degree (depraved heart) murder based upon the additional allegation of “extreme indifference to human life.” The defendant was convicted of the murder and the charge was upheld on appeal [25 and personal communication with this writer] (see FigureÂ€17.18). FiguresÂ€17.19–17.21 are from a case in which a German shepherd and a pit bull participated in a homicide. The pregnant female victim received over 50 dog bites at the direction of the owner. In addition, she was tied, beaten, and scalded; underwent an attempted hanging; was stabbed seven times in the chest; and was placed nude in a steamer trunk and discarded in –20°F weather.

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Figure 17.17â•‡ Husky claw and bitemarks on the thorax, back, neck, throat, and skull. Note the underlying hemorrhaged

tissue.

The accused, a pastor of the Universal Life Church of Enlightened Reason, claimed the victim was a witch possessed by the devil. He claimed that he was performing an exorcism on his former secretary. The dog bites were principally inflicted by the pit bull and were on the victim’s arms, forearms, and legs. Of the over 50 bites, 27 were individually identifiable. Part of the leg was avulsed (FiguresÂ€17.19 and 17.21). The primary cause of death was attributed to the seven stab wounds and hemorrhagic shock as result of blood loss. The lungs were punctured, the bronchial tubes severed, and the liver and kidney also affected by the knife wounds. Both dogs were captured and destroyed by authorities, autopsied, and tested for rabies. The latter was performed in the event the accused later claimed the dogs

were rabid and that he had no control over them. The dogs were not rabid. 17.2.6â•…Deathbed Bitemarks FigureÂ€17.22 illustrates a case of multiple bitemarks on a lower lip made by a retriever. The dying victim was lying on a chesterfield when the dog tried to wake the victim by nibbling at the lip with its four shorter anterior teeth. The alternate light imaging photograph (lower left) shows multiple nibbling of the vermilion border and inner aspect toward the center left of the lip, while the color photographs demonstrate perforation mainly toward the center right of the lip (four teeth from opposite arches).

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227

Figure 17.18 Head (upper left), anterolateral neck (upper right), left arm (lower left), right arm (lower right) injury. (Photos courtesy of Dr. Daniel M. Winter.)

Figure 17.19 Multiple dog bitemarks on the arms and legs with tissue avulsion. Note the caliper for measuring linear distance between puncture marks.

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17.3 Forensic Nightmare: Misdiagnosis

Figure 17.20 Multiple dog bitemarks on the arms and forearms.

A 7-year-old white female was found dead and mutilated in her basement. Laser analysis was conducted on the victim’s body and no fingerprints were found. No DNA other than the victim’s was found in fingernail clippings. The victim was not sexually molested. A pathologist performed an autopsy and concluded that there were (1) multiple cutaneous abrasions and contusions, (2) exsanguination, and (3) excision of the scalp (with a pair of scissors). He attributed the cause of death to more than 80 stab wounds created by scissors and/or knives. The child’s blood was not found on any clothing elsewhere in the house, nor was there blood found on any knives or scissors. The single mother was charged with seconddegree murder 11 days later. She was refused bail and was placed in isolation for her own protection; social services took custody of her other children. Although the pathologist was aware of the presence of a pit bull in the victim’s basement at the time of death, a forensic dentist was not summoned at autopsy. The pit bull’s owner, a friend of the mother’s, told police that the dog had a “reddish” substance on him when summoned from the basement prior to the discovery of the body. The victim’s blood was later found on the shaved dog hair and dog collar. The dog’s owner also told police that the dog feces subsequently contained hair. The pit bull owner had the dog destroyed 2 months later for a “nipping and biting” incident. During all of this time, authorities (police, veterinarian, pathologist, odontologist) failed to isolate, examine, and take the dog’s dental impressions. When a test for rabies was conducted, the dog’s head was destroyed and thus no longer available. The odontologist concluded: The marks found on the [autopsy] photographs are completely inconsistent with dog bite marks be they either domestic or wild. I base this conclusion on the following findings: the markings are the wrong shape to be dog bite marks. The markings on the deceased are linear incisions rather than conical punctures which are typical of dog bite marks. … In summary I can say without equivocation that the markings seen on the deceased are not dog bite marks.

Figure 17.21 Multiple dog bitemarks on the legs with avulsion.

The odontologist’s report preceded the pathologist’s by 2 weeks. Defense counsel consulted an odontologist and a pathologist. Available reports were reviewed and crime scene and autopsy photographs assessed. Both defense experts attributed the injuries to animal bitemarks.

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Figure 17.22 Color and ALI no. 12 filter (lower left) photos of dog bitemarks on a human lower lip.

The following month, the prosecution’s pathologist testified at the preliminary hearing and under crossexamination professed that it “was absurd to think that the marks on the body could be attributed to a dog” and “as absurd as it is to think that a polar bear attacked [the victim], so is it equally absurd that it’s a dog wound.” The defense informed the prosecution of its experts’ conclusions. The accused, a welfare recipient, fired her lawyer and obtained the services of a new one. The prosecution made an application for an order to have the child’s body exhumed and halted judicial proceedings pending the results of a second autopsy. Twenty-five months following the alleged homicide, defense counsel made a new application for bail, this time unopposed by the prosecution. As part of her condition for release to a halfway house, the accused was not permitted to contact either her children or any of the witnesses in the case. She remained under house arrest and was escorted on outings. A new pathologist performed an autopsy of the exhumed remains. Present were the original pathologist and odontologist and the experts representing the defense’s interest. The body was poorly preserved. The right humerus, some vertebrae, the skull, and the mandible were kept for ulterior examination. The new conclusions were that a dog was responsible for at least some of the injuries, but their location or numbers were not indicated. In addition, “the possibility that a

weapon was also involved in the infliction of the injuries is not excluded by the second autopsy,” again without naming the location, type of weapon, or number of injuries that might have been produced by this (these) unnamed mysterious weapon(s). Oddly enough, the examination of the retained bony specimens was deferred to the odontologist who had failed to identify the soft tissue injuries correctly as bitemarks in the first place. The reports date 2 years and 3 months after the alleged homicide. The judge ordered the original pathologist to write a second report in light of the second autopsy results. His new conclusion was that “because death resulted not from a single injury but the combined effect of numerous injuries, it is not possible along morphological grounds alone to determine the relative responsibilities of the noncanine versus the canine-like injuries in causing the death.” Despite the admitted presence of the dog bites, the prosecution claimed that there was sufficient evidence to proceed with a trial despite the fact that no weapon was ever found. The alleged motive for the murder was that the mother was angry at the child for having head lice. On the basis of all the evidence in the case, there is a reasonable prospect of conviction. Therefore, the Crown [prosecution] has no intention of withdrawing the charges. I wish to make that clear, since you have made at least three requests so far for withdrawal, and

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I do not want you to be under the mistaken impression that this is a possibility.

The prosecution now claimed that the dog had simply “interfered” with the body. The prosecution consulted many other experts including a fiber analyst, an entomologist, an animal behaviorist, a bloodstain pattern analyst, and a toxicologist. Three months before trial, the prosecution consulted an anthropologist, who examined the skull and vertebrae and concluded: The marks on the skeletal remains were caused by dog bites except for eight or nine marks on the skull. Of these markings, some were described as incisions along the skull caused by a scalpel or a very sharp knife. The cutting instruments seized by the police were all excluded as being the cause of the marks on the skull.

The last sentence of the report concludes: While osteological analysis is important in a case like this, the best analysis of trauma is conducted using skin and bone. Skin is more accurate in recording trauma, while bone is more permanent. It is only with the combination of the pathological and anthropological examination [of] the whole body that accurate assessments can be reached.

Ironically, the anthropologist was mistaken in at least one conclusion because the crime scene and autopsy photographs were not presented for his examination. The prosecution dropped all charges the week before trial “since it no longer has proof that this death was caused by stab wounds.” The accused spent almost 4 years awaiting trial for a murder that never occurred, grieved over the death of a child, lost custody of her other children, and became a social outcast. The following week a $7 million lawsuit was launched against the original pathologist, the odontologist, the police, and the prosecutor’s office for malicious prosecution, false imprisonment, and gross negligence. As of this writing for the second edition of the book, 13 years have elapsed and a settlement has yet to be reached. 17.3.1â•…Pattern Distribution on the Arm Spitz [26] defines blunt trauma injury as one of three basic types: contusion, abrasion, or laceration. A contusion (bruise) signifies hemorrhage into the skin, the tissues under the skin, or both. An abrasion is a scraping and removal of the superficial layers of the skin. A laceration is a tear produced by blunt trauma. Sharp force injury results from penetration of a pointed instrument into the depth of the body, causing a wound that is deeper than its length on the skin.

Figure 17.23â•‡ Different views of pit bull bites on the right arm.

FigureÂ€ 17.23 depicts the pattern distribution on a victim’s right arm. Bruising and lacerations are more apparent on the inner aspect of the arm (bottom photo), while penetrating wounds abound on the outer surface. 17.3.2â•…Wound Patterning on the Neck Neck trauma is illustrated in FigureÂ€ 17.24. Note the similarity in pattern distribution and injury on the neck and scalp produced in the fatal pit bull attack to those produced in a fatal bear attack (FigureÂ€17.8). A bitemark pattern on the neck may vary greatly in size and in shape depending on the bitemark recipient’s head and neck movement (flexion, extension, rotation, etc.), the animal’s dentition, and its head movements. 17.3.3â•…Direction of Wound Patterning on the Neck FigureÂ€ 17.25 depicts a close-up view of pit bull bitemarks on the neck. All of the neck wounds are sloping perpendicularly to the neck and oriented in an anteroposterior direction.

Carnivore Bitemarks

Figure 17.24 Different views of pit bull bites on the neck.

Figure 17.25 Neck trauma from pit bull dentition.

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17.3.4â•…Bitemarks on the Back In FigureÂ€17.26, the original overexposed photograph of the back and the “corrected” version reveal a wealth of information. The original overexposed color photograph was digitized and corrected for brightness and contrast. The imprint of five lower anterior teeth can be seen at the tip of the black arrows. These contusions were evidently inflicted when the victim was alive since they represent an inflammatory response. Given that the back is a relatively flat surface, a dog is unable to open its jaw sufficiently wide to obtain contact of the canines to skin. The bitemark pattern is markedly different from those on the arm, the neck, and the skull. Tracing a path from the five contusions toward the right shoulder, a region devoid of blood can be observed. This is the result of the dog dragging its chin along the child’s back. The yellow

arrows represent claw marks. Within the blue and black ellipses are intersecting bitemarks and claw marks. Another bitemark is present on the left scapula. Note the absence of the canine teeth in this bitemark also. Despite the fact that an ABFO no. 2 scale was used in two of the initial autopsy photographs, neither pathologist nor odontologist diagnosed the dog bitemarks (FigureÂ€ 17.27). The photograph on the left depicts five contusions representing five anterior teeth. The right photograph presents a similar pattern with an intersecting claw mark. 17.3.5â•…Clothing The relationship between torn clothing and underlying tissue trauma cannot be overemphasized (FigureÂ€17.28). The prosecution’s fabric specialist claimed that R2 may

Figure 17.26â•‡ Overexposed photograph of the back and “corrected” version.

Figure 17.27â•‡ Pit bull bitemark on back and an intersected bitemark.

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Figure 17.28â•‡ Diagram of clothing and clothed victim.

have been caused by normal wear-and-tear or by a pointed blunt instrument. R3 resulted from a dullbladed instrument and suggests that the bladed instrument may have penetrated more than once. R4 was a very clean-cut “L” shape produced by a sharp instrument and created by the pathologist cutting the garment from the body. If a bladed instrument is the cause of the tears in the T-shirt, where are the corresponding skin lesions? Where are the corresponding T-shirt perforations over the right arm from the alleged stab wounds? 17.3.6â•…The Humerus The defense’s forensic odontologist and the prosecution’s anthropologist arrived at the same conclusions regarding the humerus. The humerus demonstrated shallow, U-shaped parallel striations consistent with the carnivore dentition. There were no signs of sharp instrument markings from knife or scissors. Moreover, there were no penetrating injuries to the bone representing the tips of either knife or scissors. 17.3.7â•…The Mandible The original pathologist described the mandibular injury as follows: “The right jugular and sterno cleidomastoid region bore penetrating stab and incised injuries with one penetrating injury also present at the inferior angle of the right mandible and others more superficially over the right mandibular skin.” This was the extent of the mandibular examination.

Not a single prosecution expert witness (two pathologists, an odontologist, and an anthropologist) examined and described the injury to the retained mandible from the second autopsy. There were, after all, six separate reports from these experts. The fracture at the angle of the right mandible was examined on the dried specimen by the defense odontologist. The compression fracture was consistent with what would have been produced by a dog’s canine tooth rather than as the result of a sharp instrument blow such as a knife or scissors. The overlying soft tissue injury can be observed in FiguresÂ€17.24 and 17.25. 17.3.8â•…The Skull and Cervical Vertebra: Holes and Bitemarks There was a round puncture mark in the midsquamous area just left of the midline occipital that measÂ�ured 4.6 mm in diameter (FigureÂ€17.29). A second oval puncture on the left temporal bone above the external auditory meatus in the squamous area of bone measÂ�ured 4.8 mm vertically and 7.6 mm horizontally. According to the autopsy report, the occipital and temporal perforations were beveled on the inner table but did not open directly into the cranial cavity. A third puncture over the left mastoid region broke through the outer table only and measÂ�ured roughly 9 mm. The distance, from center to center, between the latter two defects was 34 mm. The shape, size, and distance between these two perforations are consistent with a dog’s canine teeth within the same dental arch. FigureÂ€ 17.32 depicts numerous parallel

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Figure 17.29â•‡ Location of the three skull perforations.

Figure 17.30â•‡ Various indentations on the skull.

indented U-shaped striations on the skull consistent with the carnivore dentition. FiguresÂ€17.30–17.33 depict various areas of interest on the skull. One such area involved the use of a sharp instrument on the skull in the posterior right lateral region (FigureÂ€ 17.31, left, and FigureÂ€ 17.33). The three sharp parallel marks highlighted between the arrows were made with an implement similar to the one used

to produce a fourth test mark between the two dots— namely, a scalpel blade. The three parallel scalpel marks coincide with a region of remaining scalp that would have been reflected during the first autopsy (FigureÂ€ 17.36). The prosecution implied that the marks were produced by the unfound murder weapon. It is interesting to note that the entire periphery of missing scalp on the skull was devoid of knife or scissor or scalpel markings. Would

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Figure 17.31â•‡ Areas of interest on the skull.

D A

C

Figure 17.32â•‡ Various indentations on skull.

Figure 17.33â•‡ Scalpel blade markings on skull.

not the tip of the knife or scissors have been implanted somewhere on the skull surface if it were the method used to scalp? FigureÂ€17.32 includes indentations on the skull. Oval A depicts the dog’s anterior tooth alignment.

impression. The impression was introduced as evidence at the 14-day preliminary hearing and returned to the pathologist for safekeeping. That impression has never since been located. The original autopsy radiographs have also been misplaced.

17.3.9â•…“Blood Wiping” on the Skull

17.3.11â•…The Avulsed Scalp

There is blood wiping along the back as well as the top left-hand side of the skull (FigureÂ€17.28).

The blood-soaked scalp was never swabbed for the presence of animal DNA at the original autopsy. Despite the 2.5-year custody, the initial pathologist had yet to shave the avulsed scalp to observe the presence or absence of lacerations, abrasions, etc., on the external surface of the scalp and to associate or disassociate any corresponding subcutaneous hemorrhage and scalp perforations. The fixed scalp was shaved during the second autopsy and viewed against an autopsy light. The transilluminated scalp confirmed the presence of a vital bitemark of

17.3.10â•…Impressions and X-rays During the first autopsy, the pathologist took an impression of the perforations of the skull. There was no mention of the protocol followed, the materials utilized, or the results obtained in the autopsy report. There was no mention either of the odontologist’s examination of the

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animal origin. Despite this finding, the second pathologist’s cursory examination of the scalp simply reported: “The scalp is distorted by fixation and shows areas of postmortem sectioning. There are also several defects, which invariably penetrate the scalp.” The prosecution’s odontologist submitted a report on the examination of the retained skull from the second autopsy, but he also failed to examine, analyze, and correlate the findings to the available scalp. In fact, he had failed to examine and analyze the scalp’s evidentiary value for his first report. A dog bite pattern on the scalp will be markedly different in appearance from those found on other areas of the body. The scalp is relatively fixed, large, and curved. The physical characteristics of the scalp are different when it is detached. A single wound produced by a canine tooth must be distinguished from a claw mark, for example.

17.3.12 Size of Defect on the Skull versus Avulsed Scalp The perimeter of the missing scalp should have been measured on the skull at the first autopsy. This meas ure should have been compared to the perimeter of the avulsed scalp. This could have been determined if any of the avulsed scalp was missing or lost or could have been ingested by the dog. When comparing size and shape of the avulsed scalp to the missing scalp on the skull, it would appear from photographic evidence that a portion of the avulsed scalp is missing. This would be consistent with the dog’s having eaten part of the scalp and the dog owner’s statement of finding hair in the dog feces. The periphery of the missing scalp on the skull and periphery of the avulsed scalp can best be measured by aligning string along its outer border. Figures 17.34–17.36 show different views of the skull and missing scalp. Figure 17.36 demonstrates the

Figure 17.34 Skull views with missing scalp from a fatal pit bull attack.

Figure 17.35 Skull with scalp missing.

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Figure 17.36â•‡ Orientation of perforating bite and residual tissue.

Figure 17.37â•‡ Caliper measÂ�ureÂ�ments of perforations on avulsed scalp.

relationship between two skull perforations and the remaining scalp tissue. As the prosecution’s anthropologist pointed out, “While osteological analysis is important in a case like this, the best analysis of trauma is conducted using skin and bone.” The canine perforations depicted are from the same dental arch and 3.4 cm apart. A line drawn perpendicular to the midpoint orients toward the back of the skull. The third perforation at the back of the skull and the remaining soft tissue orient toward the top left of the skull (FigureÂ€ 17.36, right). The latter was therefore not created at the same time as the two other perforations by the additional fact that the distances between all three would make it impossible.

together with the aforementioned factors, suggests a minimum of four bites would have been needed for scalp avulsion. It is interesting to note that, even though the avulsed scalp had been fixed for over 2 years, the intercanine distance had been relatively well preserved with minimal shrinkage of the tissue (FiguresÂ€ 17.37–17.39). The base measÂ�ureÂ�ment utilized to compare scalp shrinkage was 3.4 cm—the distance between the perforations on the skull. To demonstrate intercanine distance and the relationship of the other six anterior teeth, dental models were made of another dog (the suspect dog having been destroyed) and compared to the avulsed scalp (FigureÂ€17.38).

17.3.13â•…Size and Location of Perforations on the Scalp

17.3.14â•…Tissue Vitality and Transillumination

The size, location, and orientation of perforations on the scalp can indicate the direction of scalp removal. This can be associated with and compared to the skull tooth markings. The size of the missing scalp from the skull,

Blood vessel engorgement and subcutaneous hemorrhage can be visualized in transilluminated tissue when they exist. Both phenomena are the result of the inflammatory process, which by definition can only take place in the living.

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Figure 17.38 Dentition apposition with the bitemark on the avulsed scalp.

Figure 17.39 Three views of the avulsed scalp with a vital bitemark outline.

Figure 17.39 shows three views of the avulsed scalp. The photograph on the left is the avulsed scalp at the first autopsy prior to fixation. The middle photograph depicts the fixed transilluminated scalp after shaving at the second autopsy. Lastly, the right photo shows the entire shaved resected fixed scalp. Contusions, lacerations, perforations, and associated subcutaneous bleeding are evident. 17.3.15 Failures of the First Autopsy It would be futile to critique a case without learning from it. Were there system failures? How can these failures be prevented in the future? Who is ultimately responsible? What are the forensic lessons to be learned? The last question is better answered by the failures in the autopsy protocol. They can simply be listed as failure to:

1. Take DNA swabs of the body and wounds, clothing, and avulsed scalp for the presence of animal DNA. 2. Recognize the patterned injuries as bitemarks. 3. Request the presence of the forensic dentist at autopsy. 4. Interpret blood smear with the patterned injuries of the back and the skull. 5. Analyze and associate marks on the clothing to the patterned injuries. 6. Take adequate impressions of the bitemarks and the perforated skull. 7. Measure the peripheral dimension of the avulsed scalp. 8. Measure the peripheral dimension of the missing scalp on the skull. 9. Shave and analyze the abrasions, contusions, etc., and the pattern distribution.

Carnivore Bitemarks

10. Correlate the latter to the markings on the skull. 11. Transilluminate the avulsed scalp. 12. Analyze the marks on bone (humerus, skull, jaw, and vertebrae). 13. Recommend, seize, quarantine, examine, and take impressions of the dog’s dentition. 14. Have a rabies test performed. The forensic pathologist’s principal duty is to diagnose and arrive at conclusions for the cause and manner of death. The misdiagnosis of bitemarks for stab wounds changed the manner of death from accidental to homicide. In turn, this led police up an erroneous investigative path. This does not excuse investigators since the factual evidence did not match the thesis of homicide. When motive is reduced to the presence of hair lice, a weapon cannot be found despite the limited time between the discovery of the body and the alleged homicide, and the alleged murderer does not have the victim’s blood on her clothing in a stabbing death, one needs to question the thesis. In addition, when known facts are completely disregarded, such as the presence of a dog at the death scene, one can expect trouble. Failure to obtain physical evidence from the suspect dog for comparison with victim evidence is substandard protocol. When a defense lawyer can differentiate dog bites from stab wounds and a pathologist and odontologist cannot, one needs to question the experts’ education, knowledge, training, experience, and credentials. When the court declares a person an expert witness and that person is not board certified in that specific forensic discipline, one needs to question the system. While it is true that in certain jurisdictions board certification in forensic disciplines is unavailable or does not exist, international boards in that specific discipline may exist. Any pathologist or dentist can claim to be a forensic expert. Board certification in a forensic discipline assures the trier of fact of basic knowledge, education, experience, and training of the expert in that forensic discipline. Moreover, certain ethical standards are maintained by that individual, the person can be peer reviewed, and he or she must keep current in knowledge, standards, and procedures of the discipline and be recertified on a timely basis. 17.3.16 Failures of the First Autopsy Report Aside from the misdiagnosis of cause and manner of death, the first autopsy report failed in other respects. It should have reported the following: • Names of persons present at the first viewing • Names of persons present at autopsy (2 days later)

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• Name or names of the person or persons taking the autopsy photographs • Name of the person performing the dissections (denar or pathologist) • Listing what was performed at the initial viewing separately from the autopsy • Tests ordered and/or recommended other than toxicology • Description of the chain of possession of various exhibits 17.3.17 Forensic Lessons to Be Learned The death of this child and subsequent murder charges against the mother underline important issues concerning medical and dental expert witnesses: accountability, coordinating and integrating all factual and forensic elements in the case, and board certification. Crime scene investigators and the pathologist set the tone for a police investigation. In this case, the manner of death was established as homicide when it should have been listed as accidental. The cause of death was established as stab wounds by knife or scissors; it should have been dog bites. Forensic conferences periodically debate the theme of how much factual or related information a forensic expert should receive before undertaking a case. Failure to obtain as much factual information as possible prior to autopsy can prove disastrous. Moreover, having different experts examine individual exhibits separately without having factual knowledge of the case can lead to wrongful conclusions. The evidence must match the facts and vice versa. In this case, the erroneous conclusions of both pathologist and odontologist “fit” into the investigative theme of homicide despite an incredibly flimsy motive and lack of a weapon. A forensic expert’s background, training, education, skill, and experience are at issue. An opinion is to an expert witness what a diagnosis is to a physician or dentist. An erroneous opinion is potentially catastrophic. Liability may result from such opinions. Board certification may soon become a prerequisite to testimony in North American courts for all forensic disciplines. This statement was written in 2004 for the first edition of this book and was one of the recommendations of the National Academy of Sciences report in 2009 [27]. Today, anyone with a dental degree or pathology certificate can call himself or herself a forensic dentist or pathologist. The term is nonrestrictive and does not denote the claimant’s forensic background, forensic education, forensic knowledge, forensic training, forensic skill, or forensic experience. Relatively few forensic dentists or pathologists are practicing in North

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America, and virtually all reside in or travel to metropolitan areas where forensic autopsies are performed. Their forensic education, training, knowledge, skill, and experience vary greatly from one jurisdiction to another. The limited number of dentists and pathologists actively involved in the practice of forensic dentistry and pathology precludes the viability of certifying boards in the different provinces and states. As a result, in 1976, this author and seven colleagues founded the American Board of Forensic Odontology—the certifying body in forensic dentistry for North America. The objective of the board was to establish, enhance, and revise as necessary standards of qualification for those who practice forensic odontology and to certify as qualified specialists those voluntary applicants who comply with the requirements of the board. In this way, the board aims to make available a practical and equitable system for readily identifying those persons professing to be specialists in forensic odontology who possess the requisite qualifications and competence. Certification is based upon the candidate’s personal and professional record of education, training, experience, and achievement, as well as the results of a formal examination [28].

12. Sacks, J. J., L. Sinclair, J. Gilchrist, G. C. Golab, and R. Lockwood. 2000. Breeds of dogs involved in fatal human attacks in the United States between 1979 and 1998. Journal of American Veterinary Medicine Association 217 (6): 836–840. 13. Centers for Disease Control and Prevention. 1997. Dog bite related fatalities in the United States in 1995–1996. Journal of American Medical Association 278 (4): 278–279. 14. Lauridson, J. R., and L. Myers. 1993. Evaluation of fatal dog bites: The view of the medical examiner and animal behaviorist. Journal of Forensic Sciences 38 (3): 726–731. 15. Sacks, J. J., R. Lockwood, J. Hornreich, and R. W. Sattin. 1996. Fatal dog attacks, 1989–1994. Pediatrics 97 (6): 891–895. 16. Avis, S. P. 1999. Dog pack attack: Hunting humans. American Journal of Forensic Medicine and Pathology 20 (3): 243–246. 17. Sacks, J. J., L. Sinclair, J. Gilchrist, G. C. Golab, and R. Lockwood. 2000. Breeds of dogs involved in fatal human attacks in the United States between 1979 and 1998. Journal of American Veterinary Association 217 (6): 836–840. 18. Calkins, C. M., D. D. Bensard, D. A. Patrick, and F. M. Karrer. 2001. Life-threatening dog attacks: A devastating combination of penetrating and blunt injuries. Journal of Pediatric Surgery 36 (8): 1115–1117. 19. de Munnynck, K., and W. Van de Voorde. 2002. Forensic approach of fatal dog attacks: A case report and literature review. International Journal of Legal Medicine 116 (5): 295–300. 20. Dorion, R. B. J. 2001. Pattern injuries on the deceased. References AAFS meeting, odontology section, Seattle, WA, Feb. 23, 1. http://www.who.int/en/ 2001. 2. Murmann, D. C., P. C. Brumit, B. A. Schrader, and D. R. 21. Dorion, R. B. J. 2001. Pitfalls in documenting and preSenn. 2006. A comparison of animal jaws and bite mark serving bitemark evidence in pediatric death. AAFS patterns. Journal of Forensic Sciences 51 (4): 846–860. meeting, odontology section, Seattle, WA, Feb. 23, 2001. 22. Dorion, R. B. J. 2002. The Sharon Reynolds case. AAFS 3. http://tchester.org/sgm/lists/lion_attacks.html meeting, odontology section, Atlanta, GA, Feb. 14, 2002. 4. Rollins, C. E., and D. E. Spencer. 1995. A fatality and the American mountain lion: Bite mark analysis and profile 23. Klim-Lemann, J. W., and G. S. Golden. 2003. Bitemark analysis in the mauling death of child: A case study. AAFS of the offending lion. Journal of Forensic Sciences 40 (3): meeting, odontology section, Chicago, IL, Feb. 21, 2003. 486–489. 24. Sur, A. K. Y. 2003. What drives a dog to bite. AAFS meet 5. http://jasperwildlife.com/Fatal-Bear-Attacks-in-Northing, odontology section, Chicago, IL, Feb. 21, 2003. America-Jasper-Wildlife.html 25. Winter, D. M., and C. Biggs. 2003. Christopher Wilson: 6. ht t p : / / w w w. ny d a i l y n e w s . c om / n e w s / n at i on a l /â•‰ Unintentional second-degree murder conviction for a 2010/03/12/2010-03-12_teacher_mauled_to_death_by_ killing committed by dogs. AAFS meeting, odontology wild_wolves_while_jogging_in_alaska_police_say.html section, Chicago, IL, Feb. 21, 2003. 7. http://www.cdc.gov/ 26. Spitz, W. U., ed. 1993. Medical legal investigation of 8. h t t p : / / w w w. d o g e x p e r t . c o m / F a t a l D o g At t a c k / death: Guidelines for the application of pathology to Fataldogattackhome.html crime investigation, 3rd ed., 199–310. Springfield, IL: 9. http://www.dogbitelaw.com/Dog_Attacks_1982_ Charles C Thomas. to_2006_Clifton.pdf 27. The National Academy of Sciences. 2009. Strengthening 10. http://www.scribd.com/doc/10150239/Breeds-of-dogsforensic science in the United States: A path forward. involved-in-fatal-human-attacks Washington, D.C.: National Academies Press. 11. http://americaagainstbsl.tripod.com/fatal_dog_attacks. 28. Background, functions and purposes of the American html Board of Forensic Odontology, Inc.

18

Human Bitemarks Robert B. J. Dorion Contents 18.1 Introduction 18.2 Factors Affecting Bitemark Dynamics 18.3 Alive Recipient of the Bitemark 18.3.1 Child 18.3.2 Adult 18.3.3 Specialized Hospital Centers 18.4 Recipient of the Bitemark in the Twilight Zone 18.5 Deceased Recipient of the Bitemark 18.6 Bitemark Distortions 18.7 Hair 18.8 Orifices 18.9 Amputation/Avulsion 18.10 Foreign Objects 18.11 Dentition 18.12 Immobile Tissue 18.13 Bite Overlap 18.14 Pigmentation 18.15 Photographic Perspectives 18.16 Healing and Old Bitemarks 18.17 Antemortem Bitemarks 18.18 Postmortem Trauma 18.19 Clothing 18.20 Tissue Preservation 18.21 Self-Inflicted Bitemarks 18.22 Multiple Bitemarks 18.23 Muscle 18.24 Digits 18.25 DNA 18.26 New Evidence 18.27 Blunt Trauma Injury 18.28 In the Presence of Other Trauma 18.29 Single Arch Bite 18.30 Circumferential versus Linear Distance 18.31 Erectile Tissue 18.32 External Pressure Bitemark 18.33 Positional Changes 18.34 Opposite Sides 18.35 One-Sided Bite References

241 242 243 244 245 246 247 247 248 248 249 251 253 253 259 259 260 261 263 264 266 268 269 269 270 271 272 272 272 273 273 273 274 275 275 275 276 276 281

18.1â•…Introduction Class characteristics distinguish bitemarks from other patterned injuries. Rectangular (incisors and laterals) and circular/oval (canines) contusions and/or

indentations are aligned to form round to oval opposing patterns representing maxillary and mandibular tooth arrangements in the human (FigureÂ€ 18.1). The size, arrangement, and overall diameter distinguish adult from child dentitions. Thus, the class characteristic

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Class Characteristics • Oval to round shape • Arches opposing each other • Max/min arch dimension • Human/animal • Adult/child • Rectangular contusion of centrals and laterals

Figure 18.1â•‡ Class characteristics of the bitemark. Individual Characteristics Arch Characteristics

Dental Characteristics

• Rotated teeth

• Wear pattern

• Buccal or lingual

• Notching

• Mesiodistal drifting

• Angulations

• Horizontal alignment

• Fracture

Figure 18.2â•‡ Individual characteristics of the bitemark.

identifies the group from which it originates: human, animal, fish, or other species. In 2006, following this author’s proposal, the American Board of Forensic Odontology divided individual characteristics, which is a feature, trait, or pattern that represents an individual variation rather than an expected finding within a defined group, into two subgroups (FigureÂ€18.2) [1]: 1. Arch characteristic is a pattern that represents tooth arrangement within a bitemark. For example, a combination of rotated teeth, buccal or lingual version, mesiodistal drifting, and horizontal alignment contributed to differentiation between individuals. 2. Dental characteristic is a feature or trait within a bitemark that represents an individual tooth variation such as unusual wear pattern, notching, angulations, fracture.

The number, specificity, and accurate reproduction of the individual characteristics together with the evidentiary value of the bitemark contribute to the overall assessment in determining the degree of confidence that a particular suspect made the bitemark.

18.2â•…Factors Affecting Bitemark Dynamics There are many factors affecting bitemark dynamics; some are associated with the bitemark recipient and

others with the biter, the recording, and the preservation of the evidence, as well as miscellaneous factors. One of the many problems involved with experimental bitemarks is that the circumstances and the factors involved with each bitemark can never be duplicated. There are nearly 100 factors listed in FigureÂ€18.3, and controlling for each and every factor experimentally, particularly in the living, would be impossible, particularly when faced with permutations and combinations of factors. The present chapter will attempt to explain the influence of some of these factors by case presentation. When a specific factor is implicated, it is not at the exclusion of others. Pretty and Sweet [2] reported on the distribution of 148 human bitemarks as follows: breast, 33%; arm, 19%; genitalia, 8%; back, 7%; face and thigh, 6% each; leg and hand, 5% each; neck, 4%; shoulder, 3%; and abdomen and buttocks, 2% each. This closely approximates Vale and Noguchi’s earlier report on 67 bitemark cases [3]. FigureÂ€18.4 demonstrates two cases of contusions on the areola. Neither case is specific enough to demonstrate class characteristics associated with the aggressors’ dentition. This does not imply that proper examination and recording of these findings are unnecessary—quite the contrary. Additional photographic evidence in the form of ultraviolet (UV), infrared (IR), or alternate light imaging (ALI) photographs, as well as supported tissue excision, transillumination, and histological examination of the specimens, might give invaluable information. FigureÂ€ 18.5, on the other hand, demonstrates not only class characteristics but also individual characteristics. Even though the class characteristics are not numerous, they are clearly those associated with an adult human dentition. Are there sufficient numbers of individual characteristics to be able to identify the perpetrator? This would depend on the case. If exclusive opportunity is at issue, where the parents are the undisputed and exclusive suspects and one of the pair is edentulous, a case might be made if the dental characteristics of the bitemark matched the other parent’s dentition. In terms of the general population, the dental characteristics seen in the bitemark might not be sufficiently specific to identify the perpetrator. On the other hand, a live victim might be able to identify the perpetrator, and the saliva deposited at the bite site would potentially confirm the biter’s identity by DNA. FigureÂ€18.6 reveals four views of a healing bitemark on an alleged rape victim. Both class and individual characteristics are decipherable from the patterned injury. The bitemark is relatively “fresh” with scab formation and originates from an adult human dentition. The next question to be asked is whether it is a self-inflicted

Human Bitemarks Biter • Physical strength • Emotional/mental state • Selectivity of tissue • Head position • Movement • Force of bite • Sucking (negative pressure) • Pinching (positive pressure) • Dentition: Natural Natural and synthetic Synthetic • Class characteristic • Individual characteristic • Occlusion • Horizontal incisal relationship • Selectivity of tissue • Mouth props • Dental fractures • Dental anomalies • Single bite • Multiple bites (overlap) • Calculus • Oral flora • Fingerprints • DNA

243 Recipient • Alive • Twilight zone • Deceased • Intrinsic factors: General health Fatness Capillary fragility Skin diseases Blood disorders Melanin Fluid imbalances Salt imbalances Systemic diseases Tissue tonus Tension lines Viscoelasticity Nonlinearity Anisotropy Drugs • Antemortem bite • Perimortem bite • Postmortem bite • Self-inflicted bite • Racial type: Caucasoid Negroid Mongoloid • Sex Male Female • Age: Child Adolescent Adult • Tissue type • Underlying tissue • Position • Movement • Physical state: Passive Struggling • State of body or corpse • Depth of penetration • Avulsion/amputation

Recording/Preserving • Accuracy in photography • Accuracy of impression • Collection • Lifting • Fixing • Preserving • Distortion • Transporting • Transillumination • Histology • SEM

Other Factors • Extrinsic factors: Clothing Elapse of time Postmortem trauma Chemicals Water Tissue distortion Artifacts Embalming Evidence collection Contamination • Environmental factors: Temperature Humidity Soil type Burial condition Bacteria Water • Entomological activity • Rodent activity • Carnivore activity • Taphonomic changes • Transportation, victim: Antemortem Perimortem Postmortem

Figure 18.3 Factors affecting bitemark dynamics.

bitemark. Analysis of the bitemark’s location on the body, the bitemark orientation, and the recipient’s dentition should resolve the issue of whether the alleged victim is the biter. There is also the possibility of DNA analysis of the bite site, assuming the alleged victim has not washed the area.

18.3 Alive Recipient of the Bitemark Figure 18.7 lists types of persons predisposed to human bitemarks. These include but are not limited to the very young, the very old, the senile, amnesiacs, the unconscious, the drugged, siblings, and victims of crime. The

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Figure 18.4â•‡ Minor contusions on the areolas.

Figure 18.5â•‡ Bitemark on the cheek.

recipient’s general health and intrinsic factors such as medication, capillary fragility, body fat, skin diseases, blood disorders, melanin pigmentation, fluid and salt imbalances, tissue tonus, tension lines, and other factors (FigureÂ€18.3) contribute to the varied appearance of a bitemark. A bitemark recipient can be alive or dead and the bitemark self-inflicted or not. The biter can be alive or can die during the commission of the crime. Or, there may be years before the biter is apprehended. 18.3.1â•…Child What are the classic signs of a battered child? The A-to-H rule (FigureÂ€18.8) is an easy guide to remember: • Abrasions • Burns and bitemarks [4,5]

• • • • • •

Contusions Dental neglect Ecchymosis Fractures (old/new, osseous/dental) General health neglect Hematoma

It is incumbent upon all health practitioners, whether in the public or private sector, to be able to diagnose the classic signs of a battered child. In the living child, one of the prime considerations in the recording and analysis of bitemarks is the healing process. FigureÂ€18.9 depicts multiple bitemarks on a child’s face. Healing proceeds at a much faster rate in the child than in the adult. FigureÂ€18.37 illustrates the same bitemarks photographed 24 hours apart. The “vanishing” bitemarks accentuate the necessity for capturing the trauma photographically when it is initially observed.

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Figure 18.6â•‡ Four photographs of a healing human bitemark on an arm. Live Persons Very young/old Senile/amnesic Unconscious/drugged Sibling (rivalry) Victim of crime

Figure 18.7â•‡ Persons predisposed to human bitemarks.

A single bitemark produced by an adult dentition on the cheek (left) and overlapping primary dentition bitemarks on the eyebrow and eyelid (right) in FigureÂ€18.10 illustrate the difficulty in interpreting single and multiple bitemarks. Adding the healing factor renders the task appreciably more complex. Multiple overlapping bitemarks are often found in cases of sibling rivalry. It is not unusual, however, to find overlapping bitemarks on the breast and genital area in sexual assault cases (FiguresÂ€18.14, 18.17, and 18.25).

What to Look For Abrasions

Ecchymosis

Burns and bitemark

Fractures

Contusions

General health

Dental neglect

Hematoma

Figure 18.8â•‡ Battered child signs, A-to-H rule.

Serial photography—taken 24 hours apart, for example—could furnish information regarding that particular child’s healing rate. In addition, it might help in assessing similar patterned injuries in other children of equal stature and health within the same family. It is not uncommon to have a favored twin inflict bitemarks on the less fortunate rival.

18.3.2â•…Adult The adult heals at a much slower rate than the child. Factors such as medication, blood disorders and a variety of other health issues, nutrition, age, and the healing pattern may vary dramatically from one adult to another. It is important when assessing bitemark evidence to get as much pertinent information from the bitemark recipient as possible. It is incumbent upon first responders and nursing, medical, and dental personnel to be able to evaluate the situation. Once primary emergency treatment has been rendered and the patient has been stabilized, forensic evaluation can be undertaken. The types of crimes usually associated with bitemarks

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Figure 18.9â•‡ Multiple facial bitemarks.

Figure 18.10â•‡ Single bitemark on cheek and overlapping bitemarks on eyebrow/eyelid.

in the living adult include rape, abduction, and battering. Elder abuse and neglect is not confined to mental or psychiatric institutions but can take place in the homes of potential victims. FigureÂ€ 18.11 depicts four photographs of a healing bitemark on the breast of a living adult female. The coloration of the surrounding tissue is yellowish. Assessing the timing of a bitemark based strictly on color changes to the tissue is not recommended in light of the variables that affect healing. Fortunately, in the living victim, an assessment can be made to corroborate or negate the victim’s version of events. Knowing the patient’s medical history and other pertinent factors (FigureÂ€ 18.3) would be valuable information, if not a requirement. Such conditions as obesity, advanced age, alcoholism, drug abuse, tobacco use, diabetes, poor circulation, malnutrition, irradiation, and stress and medication such as immunosuppressants or corticosteroids can alter the rate of healing. Lesch-Nyhan syndrome, caused by a rare hereditary recessive gene, gives rise to an enzyme deficiency (hypoxanthine guanine phosphoribosyltransferase 1) that results in an increase in uric acid formation.

This syndrome is characterized by an encephalopathy that produces developmental problems characterized by bitemark automutilation. Bitemarks have been selfinflicted during myocardial infarction [6]. FigureÂ€18.12 shows multiple healing bitemarks on a live adult Inuit female’s back. According to the patient, she was repeatedly abused and raped over months. Some of the bitemarks possess scar tissue associated with previous assaults. FigureÂ€18.25 shows multiple human adult bitemarks on the legs and thighs, and chin amputation resulting from a human bite. 18.3.3â•…Specialized Hospital Centers In this author’s jurisdiction there are specialized centers for the care and management of rape and child-abuse victims. Competent personnel in various fields of health and social services staff these centers. Minors are cared for in specialized centers within children’s hospitals, for example. Nurses, pediatricians, dentists, psychologists, psychiatrists, social services personnel, specialized units of child protection agencies, and law enforcement form

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Figure 18.11â•‡ Breast abrasion and contusions.

part of the team approach to the problem. It is incumbent upon the institution that cares for these victims to have competent and well-trained staff that can diagnose and follow not only the medical, but also the forensic protocol including photography. Some institutions might call on the services of police identification personnel for the forensic photographic requirements in a specific case. The forensic kits include a detailed questionnaire and different sterile containers for the collection of body fluids, hair, and a variety of other samples. When all of the information and evidence has been collected, it is forwarded to the forensic laboratory for analysis.

Note that the appearance of the bitemarks is really quite different from one photograph to the other. Even though the patient was on a life-support system with continued administration of anti-inflammatory drugs, it is interesting to note that the bitemarks were still present and interpretable 7 days later. Serial photographs were taken from the day of admission to the hospital, throughout the week, at autopsy, and for 3 days postmortem. The ring technique for excision of tissue (Dorion type I at the time) and transillumination were demonstrated for the first time by means of posters during the 1984 trial (FigureÂ€31.1).

18.4â•…Recipient of the Bitemark in the Twilight Zone

18.5â•…Deceased Recipient of the Bitemark

For the purposes of this edition, the “twilight zone” refers to a comatose dying patient on a life-support system. Death can occur within hours or days, or years later. FigureÂ€18.57 depicts a comatose child who was admitted to the hospital with multiple old and new fractures of the long bones and the rib cage, with multiple bitemarks and a fractured skull. She survived 7 days and presented with self-inflicted as well as second-party bitemarks. FigureÂ€18.34 depicts the same victim with several bitemarks on the calf, thigh, and leg inflicted by the same adult biter.

FigureÂ€ 18.13 depicts a bitemark with minimal contusion inflicted by an adult human dentition. Can one diagnose the timing of the bitemark in relationship to the death from this picture alone? This homicide case is an example where proper protocol for excision of tissue, transÂ�illumination, and histological analysis can confirm the timing of the bitemark. One of the classic signs of bitemark infliction after death is the presence of teeth marks, indentations, and skin perforations in the absence of the inflammatory response (blood vessel engorgement and/or subcutaneous hemorrhage). FigureÂ€ 14.34 depicts a postmortem bitemark.

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Figure 21.17 depicts a combination of antemortem and postmortem bitemarks.

18.6 Bitemark Distortions

Figure 18.12 Multiple healing/healed bitemarks on back.

Bitemark distortions can result from movement of either the recipient or the biter during infliction. Clothing and improper photographic techniques can also contribute to bitemark distortions. Figure 18.14 illustrates deformation resulting from improper autopsy technique and manipulation. Most bitemarks on the deceased should be excised following an established protocol for ring excision (discussed in Chapter 14). It is important to demonstrate by photographic means the bitemark when first observed at the crime scene, at autopsy, at the time of excision, during trans illumination, and even after fixation. If the consultant forensic odontologist was not present at autopsy and only given Figure 18.14 (right), an improper conclusion could result. It is extremely important that the odontologist obtain all of the crime scene photographs. This author has seen displacement of body, body position changes, clothing displacement and removal, etc., perpetrated by crime scene investigators on crime scene photographs. Failure to obtain such photographs can lead to improper conclusions. The odontologist should also obtain copies of the autopsy photographs regardless of type or source. Figure 18.15 illustrates three victims with breast bitemarks. All three photographs demonstrate breast manipulation and improper photographic technique. An odontologist neither was present nor directed photographic efforts in all four cases. It is incumbent upon those who first see or diagnose the bitemarks to be fully aware of the bitemark protocol, including proper photographic technique, or to contact appropriate experts. Failure to follow an appropriate protocol binds the investigation and limits interpretation and conclusions. Figure 18.16 illustrates the use of the ABFO no. 2 scale in bitemark photographs. The three circles should be clearly seen in the overview photograph. In close-up photography it would be preferable, but might prove impractical, to visualize all three circles.

18.7 Hair

Figure 18.13 Bitemark on the breast (circa 1970) prior to routine color photography.

Hair-covered skin should always be carefully examined. This includes but is not restricted to the head, pubic, genital, and axillary regions. When bitemarks are suspected, the area should be shaved preceded by the prescribed protocol for DNA collection. Figures 18.17, 18.18, and

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Figure 18.14 Distorted bitemark due to improper autopsy technique. Note stretching of the breast tissue.

18.22 in this chapter, Figure 2.3 (right) in Chapter 2, and Figure 3.2 in Chapter 3 illustrate bitemarks on the adult female pubis and genitalia where shaving was required to evaluate the bitemark properly. In Figure 18.19, the mons pubis was not shaved because of the scarcity of hair, but that did not influence the interpretation of the bitemark or that of the transilluminated tissue (Figure 14.26). Figure 18.22 reveals several barely perceptible abrasions on a homicide victim’s pubis. Care must be taken to ensure that shaving does not result in artificial abrasions. The inner aspect of the labia majora shows some tissue redness. Figure 18.18 illustrates the excised and transilluminated pubis and the relationship between the bitemark, the subcutaneous hemorrhage, and the perpetrator’s dentition. This case once again clearly illustrates that, without proper ring excision and transillumination of tissue, one could not conclusively confirm the presence of a human bitemark even if the perpetrator’s DNA were present. Note the relationship between the subcutaneous hemorrhage and the protruded lower right canine (identified by no. 2) and the palatal position of the upper right lateral incisor (identified by no. 1) of the suspect’s dental casts.

The bitemarks can also be found on the head, a unique site with special characteristics found nowhere else on the body. See Chapter 17 and Section 18.12 of this chapter for information.

18.8 Orifices There are seven natural orifices to the body: two nostrils in the nose, two ears, the mouth, the anus, and the urethra/vagina. Attention to these areas can reveal hidden bitemarks. While Figure 18.20 displays natural creasing of both upper and lower lips, Figure 18.21 reveals an arched depression on the inner aspect of the upper lip. This depression was caused by an adult human dentition. The U-shaped arch faces outward, eliminating the possibility of a self-inflicted injury. It should also be noted that there is little trauma to the outer lip and nose area, where the opposing dental arch might have rested. Was clothing or some other interference involved, or is it a single arch bite?

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Figure 18.15 Bitemark distortions due to manipulation.

Figure 18.16 Diffuse bitemark on the arm and the breast.

Figure 18.17 Overlapping bitemarks on the mons pubis.

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Figure 18.18â•‡ Excised (upper left), transilluminated pubis (upper right, lower right) and direct dental comparison

(lower left).

18.9â•…Amputation/Avulsion

Figure 18.19â•‡ Excision ring circumscribing bitemark on pubis.

FigureÂ€18.22 illustrates recent erosions and discreet ecchymosis on the anterior part of the vulva and clitoral region and on the internal surface of the labia majora of a 14-year-old homicide victim. Moderate hyperemia of the vulva is apparent. The cause of death was asphyxia by strangulation. On the internal aspect of the left labia majora, a bitemark was identified. The entire pubic area was excised and transilluminated to reveal the presence of a vital human adult bitemark (FigureÂ€18.18).

Virtually any part of the body can be amputated during a criminal act. Amputation of the nose (FigureÂ€ 19.19) and thumb (FiguresÂ€19.14 and 19.15) by a sharp instrument is illustrated in the following chapter. Body parts have been amputated by a variety of wild and domesticated animals. The human dentition has also been known to perform partial or complete amputations [7–11]. In fiction there is Hannibal Lecter, and in real life there are Andrei Chokatilo and Jeffrey Dahmer, the cannibals. There are those who perform amputations in sport (Mike Tyson) or in self-defense. FigureÂ€18.23 depicts a clean external cut to the ear. The multiple neck stab wounds would lead one to believe that a knife was probably the instrument of amputation. Examination of the medial aspect of the attached ear clearly shows a semicircular amputation of tissue (upper right). Crime scene investigators were asked to return to the scene, where they recovered the missing segment (FigureÂ€18.24). The perpetrator’s dental imprints can be clearly seen on both the inner and outer surfaces. The ear was literally torn from its base. FigureÂ€ 18.25 illustrates multiple new and old (scar tissue) bitemarks on an abused female victim’s legs. The inset photograph depicts a partial amputation of the chin by a human bite. Lovemaking, self-defense, and aggression have been cited as reasons for having bitemarks on a body. In a homicide case, the prosecutor attempts to

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Figure 18.20 Bitemark on lip. Note the indentations on the lip border.

Figure 18.21 Bitemark on inner lip. Note arch orientation (bitemark is not self-inflicted).

associate the homicide with the bitemark. The importance of establishing the timing of the bitemark is critical to the investigation and subsequent prosecution of the case. In extremely rare cases, the bitemark will signal the cause and the manner of death. Consider the following: A female was found without her tongue. The first question to be answered was whether this was automuti lation. Figure 18.26 illustrates the convexity of the dental arch facing outward. This is not a case of tongue self-amputation resulting from an epileptic seizure or accidental self-amputation. The cause of death is exsanguination and the manner is homicide. The perpetrator bit off the victim’s tongue. To this author’s knowledge, this is the first such reported case in the scientific literature.

Figure 18.26 (upper) illustrates automutilation and tongue amputation by the dentition of a second party (lower left, lower right) (not self-amputated). In the latter case, two attempts at tongue amputation took place. The dorsal surface shows one arch while the ventral surface shows two distinct bites from the aggressor’s lower dentition. The primary bite, closest to the tip of the tongue, was inflicted while the aggressor’s jaw was in a normal position. In order to bite off the tongue, the aggressor had to slide the lower jaw into an edge-to-edge tooth position. Did the victim cooperate by placing the tongue in the aggressor’s mouth? This is doubtful. The victim was probably unconscious as a result of other trauma, and the aggressor could have pulled out the tongue or the tongue could have been out already.

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Figure 18.22â•‡ Bitemarks on the pubis and internal genitalia.

Such mutilation is rare; the most common cause of an amputated tongue is accidental. People may fall or receive some other form of trauma and bite off part of the tongue. Epileptic seizure is another cause. In such instances, the dental arch imprint would be facing inward rather than outward.

18.10â•…Foreign Objects Foreign objects can interfere with the appearance of bitemarks. On the other hand, they may mimic the appearance of a bitemark (Chapter 19). One of the classic circumstances of bitemark misinterpretation results from emergency medical treatments. The injuries on the victim’s cheeks in FigureÂ€18.27 are not the result of bitemarks; rather, they are artifact produced by the tubing and the tape.

In another case, a hand injury (FigureÂ€ 18.28) is a healing bitemark and is not associated with the needle insertion or the tape. FigureÂ€18.29 depicts a healing bitemark beginning at the throat area with the suspect’s lower teeth sliding lateroposterosuperiorly toward the angle of the mandible. The adult perpetrator’s upper teeth were in contact with the child’s right cheek. This and other healing bitemarks and fractures demonstrated a history of aggression.

18.11â•…Dentition The morphological traits of alignment, rotations, incisal fractures, chipping, etc., can be transferred to the bitten object. Keyes [12] conducted examinations of over 1,000 casts, before and after trial, in an attempt to find six lower anterior teeth resembling the alignment of a

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Figure 18.23 Ear amputation/avulsion by a human bite.

Figure 18.24 Recovered bitten, amputated ear.

defendant’s teeth, without success. The accused was successfully prosecuted based on the uniqueness of the alignment of these teeth in a case involving a bitemark on a deceased’s arm. Sognnaes et al. [13] studied computer comparison of bitemark patterns in identical twins, with interesting results. Dental morphological traits can vary with the dental condition. A 4.5-year-old white female spent 6 days

on a life-support system in a hospital. Multiple selfinflicted bitemarks were found on the victim’s hands and arms, while the mother’s lover had inflicted four bitemarks on the legs. The child had seven unreported old fractures of the ribs, sternum, and leg; was deprived of basic necessities; and was psychologically tortured. Despite the fact that free dental care was available, it was not provided. The child had chronic carious lesions with

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Figure 18.25â•‡ Multiple human bitemarks on legs and thighs, and chin amputation.

Figure 18.26â•‡ Automutilation (upper) and tongue amputation by the dentition of a second party (lower left, lower right) (not self-amputated).

multiple abscesses in the upper teeth (FigureÂ€18.30). The self-inflicted bitemarks on the arms appeared as scratch marks produced by the jagged remnants of the upper teeth (FigureÂ€18.57). Differentiating the adult from the deciduous dentition in a bitemark is usually uncomplicated when both upper and lower arches are present (FigureÂ€18.31) [14]. DifÂ�ferÂ�enÂ�tiaÂ�tion becomes more complicated if only the lower arch is recorded. Not surprisingly, the lower intercanine distance is remarkably similar to that of the

permanent dentition in the late deciduous dentition stage. Differentiation becomes even more difficult when specific dental characteristics are absent in the bitemark as a result of nonregistration or if the bitemark is diffuse and healing. Not all of the teeth within a given arch are necessarily recorded in a bitemark despite its oral presence. The horizontal height discrepancy or alignment of adjacent teeth may account for its nonregistration in the bitemark.

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Figure 18.27â•‡ Medical equipment and tape producing a pattern injury on the cheek.

Figure 18.28â•‡ Aged bitemark on the wrist complicated by the presence of tape and needle.

FigureÂ€ 18.32 depicts a permanent dentition with uneven incisal heights (horizontal plane). In this example, the lower teeth most likely to register in a bitemark would be the left central and lateral incisors and the right lateral incisor. The right central incisor is out of alignment and at a lower level on the horizontal plane. The canines and, more particularly, the first bicuspids are below the level of the four incisors. The peculiarities can be recorded in the bitemark. Specific teeth may be involved with more intense markings, lacerations, or hemorrhaging as a result of the horizontal

alignment. Notwithstanding, it is important to consider the other factors that contribute to bitemark dynamics (FigureÂ€18.3). A black male child was admitted to a hospital emergency room with contusions of recent origin to the legs, arms, abdomen, chest, back, neck, and left and right cheeks. He also had a mildly displaced midshaft fracture of the right clavicle and was diagnosed with multiple nondepressed comminuted bilateral skull fractures. The child survived 3 days. A contusion of the external aspect of the left foot was noted on admission to the hospital.

Human Bitemarks

Figure 18.29 Diffuse bitemark underneath the chin, side of the mandible and the cheek.

Figure 18.30 Maxillary crowns obliterated by decay.

Figure 18.31 Multiple healing bitemarks inflicted by the primary dentition.

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Figure 18.32â•‡ Frontal views of the dentition slightly parted and in occlusion.

Figure 18.33â•‡ Multiple views of a bitemark on a foot.

The single bitemark was unusual in that it did not include all of the six anterior teeth of either arch (Figure 18.33). Five adults had had contact with the child during the week. The last persons to have contact with him were his godmother and her boyfriend. All but the boyfriend consented to providing dental impressions. The specific characteristics of the bitemark and of the dental casts permitted the exclusion of all suspects but the boyfriend. This was the first infanticide case with bitemark evidence in the jurisdiction in question. The criminal code of that jurisdiction had no provisions for taking dental impressions from an uncooperative suspect; as a result, it was unclear whether the court could order that such a procedure be performed. In an unusual tactic, the defense produced its forensic dental expert’s opinion prior to trial. The expert

witness for the defense relied solely on digitized images of the casts in the comparison. The defense expert also had the boyfriend’s dental casts, which were not provided to the prosecution. The defense expert concluded that the boyfriend could not be eliminated as the bitemark suspect, but potentially implicated other persons as its source. The crown was satisfied with this admission since it was confident that the two other named suspects in the expert’s report could be eliminated as the bitemark source. The defense changed its plea to guilty the day the trial was to begin. Although the bitemark was correctly identified at the child’s hospital admission and at autopsy, the odontological analysis was hampered by a lack of properly scaled bitemark photographs (despite the availability but nonuse of an ABFO no. 2 scale), the lack of bitemark

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Figure 18.34â•‡ Three different looking bitemarks inflicted by the same dentition.

impressions, and the unsuitability of the excised bitemark specimen. As for the mark on the cheek that the defense’s expert opined to be a bitemark, it was not (FigureÂ€18.27). FigureÂ€18.34 illustrates three unscaled bitemarks on the calf, ankle, and thigh inflicted by the same perpetrator. The variations in the appearance of the bitemark are the result of different bitemark dynamics (FigureÂ€18.3). In the three photographs, the absence of a reference scale and the improper photographic technique of the bitemarks render interpretation difficult. Normally, the upper bicuspids are more likely to register buccal and lingual cusps in a bitemark. The lingual cusps are the usual holding cusps in the maxillary arch and are more prominent than the mandibular counterparts.

18.12â•…Immobile Tissue A woman found her 14-month-old son lifeless in bed. The child was pronounced dead and his body embalmed. Because child abuse was suspected, burial was halted and an autopsy ordered. The autopsy attributed death to asphyxia by suffocation despite a lack of trauma to the hyoid and thyroid regions. The pathologist noted multiple blunt trauma injuries to the head, trunk, and extremities in various stages of healing. The right humerus and left tibia were fractured, and there was edema of the cerebrum and occipital lobe. Most of the anterior teeth had erupted, and the lips, cheeks, and frenulum were bruised. Head shaving revealed contusions over several areas of the head (FigureÂ€ 18.35). Retraction of the scalp confirmed the presence of arch-shaped hemorrhages consistent with bitemarks of human origin from an adult dentition (FigureÂ€18.36). Improperly scaled photographs, lack of bitemark impressions, embalming procedures, and burial of the tissue rendered the analysis of this case much more difficult than it should have been. The scalp is the only skin tissue of the body that is relatively immobile, with little fat or muscle support;

highly convex; and mostly supported by bone. Bitemarks from an adult dentition onto an adult scalp are less likely to be distorted as a result of skin movement than on any other skin surface. On the other hand, a bitemark is less likely to include the upper and the lower dental arches. In fact, it is more likely that only a portion of one or the other arch will be registered in a human bitemark. One to three teeth are normally registered in a bitemark rather than the ideal six to eight teeth per arch. The reasons are the convexity of the adult skull and the limitation of the opening diameter of the human jaw. It would be exceptional to find more than two or three teeth from either the upper or the lower jaw registering in an adult scalp bitemark. For this reason, the trauma produced by an adult human dentition on an adult scalp might be misinterpreted as one produced by an instrument such as a screwdriver. A human bitemark from an adult dentition onto an adult scalp will usually have less of a curvature than the dental arch that produced it. To produce more than one to three teeth in the bitemark, the victim and/or aggressor would normally need to rotate the head. The convexity of the skull also has a great bearing on the number of teeth present. This author has recently seen a full compliment of upper and lower anterior teeth in a bitemark on a skull. On the other hand, bitemarks in the facial area adjacent to the orbits, the cheeks, the ears, the nose, and the lips are more than likely to record the perpetrator’s upper and lower dental arches.

18.13â•…Bite Overlap FigureÂ€ 18.37 depicts single and overlapping bitemarks on a child’s face inflicted by an older jealous sibling. The photographs, taken 24 hours apart, demonstrate the importance of recording the trauma at the earliest possible moment. Note that the bitemark adjacent to the eye has faded considerably 24 hours later. Five overlapping semicircular ecchymoses on both the superior and lateral aspects of the left thigh of a

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Figure 18.35 Diffuse contusions on the scalp.

Figure 18.36 Underside of the scalp with diffuse semicircular contusion.

9-month-old deceased white male can be observed in the excised and transilluminated tissue (Figure 14.22). The cause of death was cardiopulmonary arrest, and the manner of death remained undetermined for this case. Additional examples of overlapping bitemarks can also be seen in Figures 14.37 (left), 18.9, 18.14, and 18.17.

18.14 Pigmentation See Chapter 7 for guidance in the photographic techniques employed in capturing trauma on highly pigmented skin such as that seen in Figure 18.33. Ultraviolet and ALI photography are probably more useful than is

color. Figure 18.38 illustrates a bitemark on a live black suspect’s back (left) and an unrelated black homicide victim’s arm (right). The appearance of the bitemark on the back can dramatically change depending upon the suspect’s body position (sitting, standing, bending, twisting, etc.). Additional examples of bitemarks on lesser pigmented individuals, such as North American Indians, are illustrated in Figures 18.6, 18.11, 18.12, and 18.25. In deceased highly pigmented individuals, transillumination is extremely useful in visualizing and diagnosing an inflammatory response (blood vessel engorgement and subcutaneous hemorrhage) (Figures 14.37, right, 14.38, and 22.24).

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Figure 18.37â•‡ Multiple bitemarks on the face photographed 24 hours apart.

Figure 18.38â•‡ Bitemarks on scapula (black male) and arm (black female).

18.15â•…Photographic Perspectives The American Board of Forensic Odontology has officially endorsed the ABFO no. 2 scale, codesigned by the late Dr. Tom Krauss, as the recommended ruler for use in bitemark photography. The scale is basically two rulers at right angles to each other with three equidistant circles and a grayscale reference. The circles are used as reference to correct angular distortion while the gray scale is used for color correction. The importance of having the scale in contact with the tissue and parallel to the plane of the film cannot be overemphasized. On a highly curved surface, such as a breast or shoulder, the importance of having pictures from several angles is essential. Unfortunately, imitation scales (FigureÂ€18.39)

use the ABFO name. The scale sanctioned by the ABFO is made by Lightning Powder Co. Ltd. There is a problem with the gray scale that can vary from batch to batch even with the same manufacturer (FigureÂ€18.39) [15]. It is important to keep track of which scale is being used. FigureÂ€18.40 depicts photographs of two highly convex surfaces, a breast (upper) and the shoulder (lower). The photographs were purposefully taken at extreme angles to display specific points of interest. The former illustrates a partially sectioned nipple observable from the projected shadow on the scale. The latter was photographed to demonstrate the convexity of the shoulder in relationship to the bitemark. Note that angle of photography and photographic lighting even accentuate the dust on the scale. Both of these photographs would be

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Figure 18.39 ABFO no. 2 scale and imitation.

Figure 18.40 Off-angle photographs of breast and shoulder bitemarks.

of little use without an appropriate scale as reference. The photograph in Figure 18.41 is of the same shoulder shown in Figure 18.40 (left). Figure 18.42 shows a human bitemark on a highly curved surface, the tip of the nose. Compare these photographs to those in Figures 1.7 and 11.8. Generally speaking, bitemarks on highly curved surfaces require more photographs than those on flat surfaces. Figure 18.43 reveals three bitemark photographs on a

cheekbone. Note the change in angulation and photographic perspective. Figure 18.44 demonstrates the same photographic perspective but with different lighting conditions. Figure 18.45 shows two views of a bitemark that lack both class and individual characteristics. Transillumination may be of great benefit in distinguishing individual dental characteristics not seen on the skin surface. Skin slippage, perpetrator and victim

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Figure 18.41 Bitemark on the shoulder photographed from different angles.

Figure 18.42 Nose bitemark photographed from different angles.

movement, clothing, shoulder convexity, and/or underlying tissue may have contributed to the lack of dental specificity in the bitemark.

18.16 Healing and Old Bitemarks The inflammatory response begins as soon as trauma has been inflicted in the living. Figure 18.46 (left) depicts a bitemark on a 7-year-old’s buttock. The photograph on the right depicts the same bitemark 27 hours later. Serial photography in the living records two phenomena: the healing process and color changes over time. Because of the many factors involved in bitemark dynamics, one should not exclusively depend on color changes for the timing of the bitemark [16]. This point has also been emphasized elsewhere in this textbook. Figure 18.47 illustrates a bitemark on the lower abdomen and on the child’s scrotum. A known pedophile was captured 24 hours after the kidnapping. Note that the healing rates in Figures 18.46 and 18.47 appear

to be different. This discrepancy is not accounted for by the healing rate, but rather by the biting dynamics. Figure 18.48 shows photographs of multiple healing bitemarks on an arm and a single bitemark on a leg of a 6-month-old male admitted to the hospital. Figure 18.58 is a photograph of the same victim taken 48 hours previously, while Figure 18.59 was taken 8 days later. The healing process in children is both rapid and dramatic. Any and all injuries should be immediately photographed with an ABFO no. 2 scale. It is incumbent upon all health professionals, caregivers, teachers, and parents to signal any such trauma to competent authorities for proper evaluation and diagnosis. Figure 18.49 illustrates opposing semicircular bruises on a rib cage. There is sufficient information to suggest that the pattern is consistent with the human dentition. Is it from an adult or a child’s dentition? The dimensions of the top arch would represent only two maxillary adult teeth (18–20 mm)—more if it was the deciduous dentition. The clue that distinguishes the culprit lies in the linear distance between the center point of the top hemorrhagic arch to the center point of the

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Figure 18.43 Bitemark on the cheek photographed from different angles.

bottom hemorrhagic arch (32 mm). The linear distance between the farthest point of the top hemorrhagic arch to the farthest point of the bottom hemorrhagic arch meas ures 39 mm. The skin on a child’s rib cage has little fat and is relatively immobile other than for the expansion/ contraction of breathing. In other words, there is little predictable bitemark distortion in this specific case for this particular area. The culprit’s mouth would therefore have an opening diameter between 32 and 39 mm. Can a child open that wide?

Even though many authors have commented on the relative inaccuracies of timing bitemark injuries on bruise coloration alone, it should be stated that “relative” timing might be the issue at hand. Aggravated assault as opposed to simple assault might be at issue. If a child’s death resulted from inflicted trauma, it might be significant to establish whether repeated assaults led to the child’s death. In combination with additional injuries, such as healing or old fractures and dental, oral, and other facial injuries, this can be used to display the aggressor’s intent. The child’s past medical and dental history should be carefully evaluated. It is incumbent upon health professionals and forensic experts to seek any and all medical and dental files that might be found in various health clinics, hospitals, social services, and dental offices. It is also important to realize that the child’s parents or guardians might have been living in other jurisdictions prior to the latest aggression. A “last partner” background check in a single-parent family is often telling. This author’s experience has shown that the new live-in boyfriend is more than likely the source of the trauma and battering. In rare circumstances, the female partner is the culprit. Figures 18.50 and 21.18 outline semicircular bruises on a right arm. These bruises as well as those depicted in Figures 18.51 and 18.52 are human bitemarks that differ considerably in appearance from each other. The female child survived 7 days in the hospital on life-support systems and eventually died of complications as a result of a fractured skull. Figure 18.52 illustrates photographs taken 8 days apart. The photograph on the left was taken upon admission to the hospital. Even though the bitemark in Figure 18.53 does not present with clear evidence of class and individual dental characteristics, the transilluminated tissue clearly demonstrates subcutaneous hemorrhage, which is compared to the suspect dentition (left). This case is unusual in that little resorption of the hemorrhage occurred in the interim 7 days. This is partially due to the victim’s medical condition, the anti-inflammatory medications administered, and her dependency on the life-support system. Some bitemarks in the living may leave permanent scars that can lead to aesthetic complications and civil as well as criminal litigation.

18.17 Antemortem Bitemarks The laws of nature are such that when sufficient trauma is inflicted in life, an inflammatory response results (blood vessel engorgement and/or subcutaneous hemorrhage).

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Figure 18.44 Change in the incidence of lighting from overhead (upper left), to off angle (upper right), to frontal (lower left), and extreme off angle (lower right).

Figure 18.45 Two views of a diffuse bitemark on an arm.

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Figure 18.46â•‡ Bitemark on a child’s buttock photographed 24 and 51 hours after infliction.

Figure 18.47â•‡ Bitemark on genitals photographed 24 and 51 hours after infliction.

2

1 4 5

6 3

Figure 18.48â•‡ Bitemark photographs taken 48 hours after those in Figure 18.59; arm (left) and leg (right).

FigureÂ€ 18.54 illustrates a contused oval antemortem bitemark. The term “perimortem” should not be used to describe the timing of the bitemark since it is a temporal nondescriptor that means “I don’t know when the bitemark was inflicted” [17]. Bitemarks are either antemortem or postmortem and can usually be differentiated macroscopically, following excision, or histologically.

18.18â•…Postmortem Trauma A 3-month-old white female was found dead in her crib. On the vulva and buttocks were lesions due to chronic diaper rash. The left thigh also presented with five pale brownish irregular indentations that, when taken together, formed a semicircular pattern suggestive of

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Figure 18.49â•‡ Two arched contusions facing each other on the lateral aspect of the rib cage.

Figure 18.50â•‡ Opposing semicircular bruises on the right arm.

a single-arch bitemark (FigureÂ€ 18.55). An impression was made and the tissue was excised, fixed, and transilluminated. There was an absence of any other marks of violence on the deceased. The cause of death was not determined. Five microscopic sections were made of the area through and around the depressions (FiguresÂ€14.33 and 14.34). There was neither hemorrhagic infiltration nor

any acute inflammatory reaction in the five sections examined. It is important to note that the histological specimens incorporated both the depressions and the area immediately adjacent to the depressions. The depressions were attributed to adult human teeth after the rough edges of a plastic diaper had been considered and eliminated as a possible source of the depressions. Note that the depressions are on the left inner thigh only.

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Figure 18.51 Ill-defined healing bitemark on the calf (left) and the arm (right).

Figure 18.52 Bitemark on medial aspect of lower leg below the calf. Photos taken 8 days apart.

While it is certain that the presence of subcutaneous bleeding would indicate antemortem injury, sufficient force must be applied to cause blood vessel engorgement and/or subcutaneous hemorrhage. If sufficient force was applied, as indicated by skin indentation and perforation, in the absence of blood vessel engorgement and/or subcutaneous hemorrhage, the biting would have taken place after death (postmortem). Can one tell if a bitemark has been inflicted antemortem or postmortem by looking at a photograph alone? In the absence of an inflammatory response, it would be impossible to tell from a color or black-andwhite photograph alone whether the bitemark was inflicted antemortem or postmortem. One would need additional information from excision of tissue, transillumination, and/or histological sections to determine the timing of the bitemark. Can one determine antemortem from postmortem bitemark infliction from ALI photography? Such photography does not distinguish an antemortem from a postmortem bitemark but does contribute invaluable

information to bitemark interpretation [18]. Information from various types of photography (color, black and white, UV, ALI), transillumination, and histology contributes specific, independent, yet complementary information to bitemark analysis. Restricting analysis to one or another grossly limits interpretation [18].

18.19 Clothing Figure 18.56 depicts a bitemark on the abdomen of a female rape victim admitted to the hospital. The unavailability of an ABFO no. 2 scale led the photographer to place two plastic rulers perpendicular to each other and to incorporate three quarters as reference points. Bitemark interpretation was further hampered by the presence of clothing when the bite was inflicted [2,3] and cellulites [4]. Consult Figures 5.10 (right), 12.6, 12.8, 12.9, 14.30, 14.31, and 22.3 for additional photographs of the appearance of bitemarks through clothing.

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Figure 18.54 Diffuse bitemark on the breast with abrasion running through it.

18.20 Tissue Preservation Case examples in this chapter and Chapters 14 and 15 and the experimental models in Chapter 21 underline the importance and significance of proper tissue excision, fixation, preservation, storage, and transportation in the analysis of bitemark evidence. Failure to maintain an adequate protocol in these matters minimizes the expert’s ability to arrive at proper conclusions.

18.21 Self-Inflicted Bitemarks

Figure 18.53 Ill-defined and transilluminated bitemark and suspect dentition; direct comparison.

Figure 18.55 Bitemark indentations on the left thigh.

Self-inflicted bitemarks are common to the literature [6,19,20]. There are two categories of self-inflicted bitemarks: voluntary and involuntary. Voluntary selfinflicted bitemarks are intentional, whereas involuntary bitemarks are categorized as accidental, medical, or third-party induced. Voluntary self-inflicted bitemarks occur for a variety of reasons, from suppression of pain to self-esteem issues to intentionally and wrongfully accusing a third

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Figure 18.56â•‡ Nonstandard scale, clothing imprint, and cellulitis complicating bitemark interpretation.

Figure 18.57â•‡ Bitemarks on the arms and the legs.

party of the bitemark or simulated bitemark (Figure 19.5). Anderson and Hudson describe that battered children occasionally bite themselves to stifle crying or to mask intense pain [19]. Accidentally self-inflicted bitemarks might result from a fall (slippery or wet surface, ice) causing lip and/ or tongue laceration or partial or complete amputation. A self-inflicted bitemark might also result from a medical condition such as loss of consciousness resulting in a fall, an epileptic seizure, neurological disorders, or a drug-induced seizure producing bitemarks on the lip, tongue, arms, hands, or fingers. Any area of the body other than the head and neck, upper thorax (except large female breasts), the back, and buttocks is a suspect area for self-inflicted bitemarks. The following case illustrates voluntary self-inflicted bitemarks to suppress pain. A comatose child was admitted to the hospital with a fractured skull and older healing and untreated fractures of the leg and rib cage.

The victim survived 8 days on a life-support system. The child was regularly beaten and, in order to prevent herself from screaming, bit herself on the arms (FigureÂ€18.57). Four additional bitemarks inflicted by her tormentor are seen on the thigh, leg, calf, and ankle in the figure. An involuntary, third-party-induced self-inflicted bitemark is illustrated in FigureÂ€ 18.64. The inner lip abrasions are the result of the perpetrator’s action to muzzle the victim to prevent screaming. In more serious cases, the lip abrasions can be associated to manual or object suffocation (pillow, etc.).

18.22â•…Multiple Bitemarks Photographs in FiguresÂ€ 18.9, 18.10, 18.12, 18.14, 18.17, and 18.25 exhibit multiple overlapping bitemarks. Many examples throughout this edition illustrate multiple bitemarks on the same victim, including experimental

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Figure 18.58â•‡ Single bitemark on the leg and superimposed bitemarks on the arm.

1

5

2

4 3 6

Figure 18.59â•‡ Bitemark photographs taken 8 days after those in Figure 18.58: arm (left) and leg (right).

Figure 18.60â•‡ Multiple bitemarks on a child’s back from a deciduous dentition.

bitemarks in Chapter 21. Suffice it to say that, from a statistical point of view, if one bitemark is found on a body, it is more likely that others are present. FiguresÂ€ 18.58 and 18.59 depict single and overlapping bitemarks in various stages of healing. See Section 18.16 of this chapter for an explanation of these illustrations. In an unrelated case, FigureÂ€18.60 illustrates multiple healing bitemarks on a child’s back. Note that the appearance of the bitemarks differs with location. Some lesions look like scratch marks while others resemble a dermatological condition. See FigureÂ€21.16 for an illustration of a hand-drawn overlay of the suspect’s deciduous dentition on one of these bitemarks.

18.23â•…Muscle In extremely rare cases, the three-dimensional class and individual characteristics of the biter’s dentition are imprinted in muscle. The bitemark in FigureÂ€18.61 was inflicted while the victim was alive, as witnessed by the intramuscular and subcutaneous hemorrhage. Why did the muscle not regain its natural shape? This phenomenon defies explanation since, in this case, the epidermis is not perforated. This author has been able to reproduce two experimental bitemarks with similar results (FiguresÂ€21.118 and 21.119), but has yet to see it in postmortem bites.

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Figure 18.61 Three-dimensional dental imprints in muscle.

18.24 Digits Bitemarks on digits are not rare but they are difficult to interpret because few of the offending teeth are normally registered; more importantly, the digits themselves can flex and can affect tooth alignment of the bitemark. Bitemarks on fingers may be willfully or accidentally inflicted during the commission of a crime. A victim might inadvertently place fingers in the aggressor’s mouth to ward off attack. Conversely, the victim might bite the aggressor’s fingers in self-defense. The aggressor might attempt to muzzle the victim in order to prevent him or her from screaming or in an attempt to suffocate the victim. Any other of the aggressor’s body parts can be bitten, but the fingers are commonly involved. See Figures 19.14 and 19.15 for a differential diagnosis of bitemarks versus other potential causes.

18.25 DNA A bitemark was discovered on a homicide victim’s breast. The principal suspect, her boyfriend, admitted to having sucked the breasts but denied having bitten or having had sexual intercourse with her. His dentition excluded him as the perpetrator of the bitemark. He remained under suspicion pending DNA results. Months later, the presence of the boyfriend’s DNA at the bite site was confirmed as well as that of another person’s. There was an absence of DNA on the raped victim’s mons pubis, genital, vaginal, and rectal areas. Empty packages of condoms littered the student’s residence, but condoms were not found. Imagine the dire consequences had bitemark analysis not been performed. The presence of DNA at a bite site does not necessarily associate it to the bitemark. In the former case,

the boyfriend’s DNA at the bite site was confirmed. Had the bitemark been inflicted through clothing, the perpetrator’s DNA could well not have been on the breast. If the body was subsequently dumped elsewhere without clothing and bitemark analysis was not performed, the DNA/bitemark association would have been erroneous. There must be a proven association between the DNA and the biter. The presence and identification of a biological substrate such as saliva, blood, semen, or hair may be confirmed by DNA analysis; however, this does not provide for the timing of the event or how the biological substrate got there in the first place (it could have been deposited by a third party). A bitemark can confirm the identification of the person who made it, the timing and aging of the bitemark, its temporal relation to the event (kidnapping, infanticide, homicide, etc.), an estimate of the amount of force applied and pain suffered, and physical descriptors of the perpetrator’s dentition. DNA cannot establish any of these parameters. All of these issues are critical in an infanticide or homicide case. The importance of a bitemark should never be underestimated. The question arises as to how many cases may have been prosecuted or overturned by the courts on DNA results when the presence of bitemarks was improperly evaluated, was overlooked, or was disregarded. How difficult would it be to contaminate the victim’s clothing with DNA evidence even years following the homicide? DNA is but a fragment of the puzzle—not its sole solution.

18.26 New Evidence Twenty-year-old Gail Miller, a nursing assistant, died of stab wounds to the chest on January 31, 1969, in Saskatoon,

Human Bitemarks

Saskatchewan. Sixteen-year-old David Milgaard was convicted of the sex slaying and was released 23 years later following a Canadian Supreme Court decision to set aside the conviction. The Saskatchewan government awarded Milgaard $10 million dollars for wrongful conviction, the largest compensation package in Canadian history thus far. On July 25, 1997, another person was charged with Gail Miller’s murder. In 2000, it was the prosecution’s contention that the pathologist had failed to diagnose a bitemark at autopsy 31 years earlier. The crown’s forensic dental expert submitted four reports. The defense’s forensic dental expert examined the crime scene and autopsy negatives and prints. At least one critical print (photograph) had been inverted in printing in the set of photographs submitted by the crown during the Milgaard trial in 1969 and subsequently at the pretrial hearing in 2000. It was the defense expert’s opinion that the patterned injury above the breast was not a bitemark because it lacked both class and individual dental characteristics. In addition, the maxillary intercanine distance was around 26–28 mm according to the crown’s defense expert—far less than the accused’s intercanine measÂ�ureÂ� ment (less also than what would be considered normal for an adult white male). The judge reviewed and ruled on the admissibility of the new bitemark and also on the results from DNA analysis of semen found on Miller’s clothing 31 years after the homicide. After listening to opposing forensic dental experts, he ruled that he did not believe in the prosecution’s “bitemark theory” and ruled it inadmissible for trial, although the DNA results were admitted. How could the nonswollen, noninflamed, circular, centrally depressed patterned injury be explained? On the coat there was a missing button. The button was too large to leave such a mark. Could it be the base or the end of the flashlight found in David Milgaard’s possession at the time of his arrest? This was also too large a diameter. The nursing insignia found on the victim’s discarded dress? Too small. What could have caused the patterned skin depression? Her nude body, draped only by a coat, was found lying face down with folded arms and watch facing the chest. The only major exhibit not retained by the prosecution was the victim’s watch.

18.27â•…Blunt Trauma Injury FigureÂ€14.41 depicts a blunt trauma injury produced by a single tooth. Note that the blood vessel engorgement/ hemorrhagic pattern surrounds the tooth’s impact site.

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18.28â•…In the Presence of Other Trauma The following cases illustrate teeth marks within other trauma. A young, mentally challenged male was found with multiple bruises on the arms, chest, and shoulders. A close-up view demonstrated multiple bitemarks within larger bruising (see FigureÂ€18.62). A female assault victim was found with multiple bruises on the left hip/ leg region. The victim recalled having been bitten once through pantyhose by the aggressor. Examination of both regions demonstrated that tooth imprints were present in both areas. She had no recollection of the second bite because she was struggling for her life and had sustained multiple stab wounds to the head, neck, and thoracic region. Observe the minute abrasions outlining the dental contact with the skin in FiguresÂ€18.63–18.65. Clearly, the quality of photography must be exceptional to pick up these minute details. FigureÂ€21.149 illustrates another example.

18.29â•…Single Arch Bite Bitemarks do not always involve the imprint of both dental arches, as the previous example and others (FiguresÂ€18.21, 18.66, and 5.12, left) demonstrate. MoreÂ�over, fewer than six teeth per arch may be recorded in a bitemark even when they are present in the biter’s mouth. This may be due to factors such as the presence of clothing, victim or suspect movement, partial anodontia, the removal of one of the set of complete dentures, the convexity of the bitten tissue, etc. A single-arch bite occurs more frequently on flat surfaces, such as the back, or highly curved surfaces such as the scalp. Clearly, the fewer the teeth registering in a bitemark, the less likely is the identification of the biter. Perpetrator identity may not be the issue, however. In a multiple-bitemark case, one looks for similarity in patterns, as depicted in FigureÂ€18.66. The blue arrows locate two skin punctures that closely resemble two other punctures outlined by the yellow arrows. These punctures are similar in size, orientation, and distance from each other. Could they have a common origin? The excised, fixed, and transilluminated specimen clearly illustrates an inflammatory response related to the punctures (blue arrows) and the absence of hemorrhage related to the puncture marks depicted by the yellow arrows. A word of caution is in order. Pigmentation in the form of freckles, the areola, or the nipple should not be misinterpreted as inflammatory response (blood vessel engorgement and/ or hemorrhage) in transilluminated tissue. The bruise to the left of the areola does not have punctures. From the same case, photographs in FigureÂ€ 21.17 demonstrate a direct comparative technique between the

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Figure 18.62 Multiple bitemarks “hidden” by other hematomas on a child’s chest and arm.

Figure 18.63 Left leg bruises and teeth marks.

excised, transilluminated tissue and a suspect dentition. The peculiar V-shaped skin puncture mark was produced by a morphologically atypical extruded canine. Three single-arch bitemarks were attributed to the lower arch. Note the absence of an upper arch registration.

18.30 Circumferential versus Linear Distance Figure 18.67 depicts some nonstandard scales: a pliable transparent acrylic scale with concentric circles used

by dermatologists to measu re the diameter of lesions (center left) and a clear pliable acetate transparency incorporating 1-mm squares (center right; a red cross centers the transparency, dividing it into quadrants). The use of this scale can help in the orientation of the bitemark and in distinguishing upper from lower quadrants and the centrals within the arches; rulers that adhere to skin (lower left) to facilitate measu re ment of circumferential distance; a clear acetate scale with 1-mm squares identified by alpha columns and numeric rows; and the Kaminski cross (upper right).

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Figure 18.64 Close-up of a leg bruise and skin abrasion from teeth.

Figure 18.65 Close-up of a leg bruise and skin abrasion with perforation from teeth.

18.31 Erectile Tissue By its very nature, erectile tissue will change shape, and it can be extremely difficult to recognize bitemark injury. Figure 18.68 demonstrates two adjacent imprints reminiscent of the human dentition on the shaft of a child’s penis. The size of the individual imprints will change depending on when the bite was inflicted—namely, during an erection or not. Biter identification is extremely difficult in this circumstance.

the oral mucosa, and the frenula can be lacerated or torn. Under exceptionally violent circumstances, there might be fractures of the teeth and/or jaws. The cause of death in the present example was asphyxia by suffocation and the manner was homicide. Other classic signs accompanied the oral manifestation of asphyxia. Readers are referred to Section 18.21 for other forms of self-inflicted bitemarks.

18.33 Positional Changes 18.32 External Pressure Bitemark Involuntary bitemarks are categorized as accidental, medical, or induced by a third party. Figure 18.69 demonstrates a third-party-induced self-inflicted bitemark resulting from the aggressor pressing and holding the child’s lips against the teeth. In certain cases, the lips,

Figure 18.70 demonstrates a positional change of the aggressor’s dentition from the top of the shoulder toward the clavicle. This positional change can also be due to jaw closure, slippage, convexity of tissue, aggressor or perpetrator movement, etc. See Figure 18.29 for another example of positional change.

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Figure 18.66â•‡ Breast (upper left): excised (upper right) and transilluminated (lower left, lower right).

FigureÂ€ 18.71 illustrates bitemark distortion due to positional changes by flexion of the arm and the leg; FigureÂ€18.72 depicts multiple bitemarks near the elbow joint. The shape of the dental arches that contributed to the bitemark changed with the extension, flexion, and rotation of the arm. See FigureÂ€3.4 for another example of flexion and extension of the arm and forearm. Positional changes resulting from joint movement render bitemark analysis and interpretation and perpetrator identification difficult.

18.34â•…Opposite Sides FigureÂ€18.73 illustrates a bitemark on the front and back of the shoulder. It is difficult to demonstrate both the

upper and the lower dental arch that contributed to the bitemark in one overall photograph (left). As mentioned in other chapters, each arch should be photographed independently under these circumstances. Photographs should be taken with the plane of the lens parallel to the bitemark or as close to it as possible. Note in this case that very few teeth have been imprinted from each arch.

18.35â•…One-Sided Bite Some bitemarks are more one sided than others (FigureÂ€18.74). Many factors can contribute to this phenomenon, including access and convexity of the bitten tissue, slippage, aggressor or victim movement, whether a joint is involved (arm or leg), etc.

Human Bitemarks

Figure 18.67 A variety of nonstandard scales.

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Figure 18.68 Marks on penis suggestive of tooth imprints.

Figure 18.69 Contusions and teeth imprints on upper and lower inner lips.

Human Bitemarks

Figure 18.70 Bitemark dynamics: sliding lower jaw on a curved surface.

Figure 18.71 Bitemark distortion due to positional change of the arm (upper) and leg flexion (lower).

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Figure 18.72 Bitemark distortion resulting from positional change of the arm/forearm.

Figure 18.73 Bitemark in front and in back of the shoulder.

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Figure 18.74 Bitemark (left) excised and transilluminated (right). (Courtesy of Dr. Bryan Chrz.)

References 1. American Board of Forensic Odontology. 2009. Diplomates reference manual. 2009. Section III: Policies, procedures, guidelines and standards. Colorado Springs, CO: ABFO. 2. Pretty I. A., and D. Sweet. 2000. Anatomical location of bitemarks and associated findings in 101 cases from the United States. Journal of Forensic Sciences 45 (4): 812–814. 3. Vale, G. L., and T. Noguchi. 1983. Anatomical distribution of human bite marks in a series of 67 cases. Journal of Forensic Sciences 28 (1): 61–69. 4. Sims, B. G., J. H. Grant, and J. M. Cameron. 1973. Bitemarks in the “battered baby syndrome.” Medicine Science & Law 13 (3): 207–210. 5. Dorion, R. B. J. 2002. Recognition of child abuse, special session, Anthrop/Path/Bio/General. Atlanta, GA: AAFS, Feb. 16, 2002. 6. Warnick, A. J., L. Biedrzycki, and G. Russanow G. 1987. Not all bite marks are associated with abuse, sexual activities, or homicides: A case study of a self-inflicted bite mark. Journal of Forensic Sciences 32 (3): 788–792. 7. Govindah, R. B. J. 1972. Traumatic amputation of a finger as a result of a human bite. Journal of Forensic Sciences 1:445. 8. Pantanowitz, L., and M. Berk. 1999. Auto-amputation of the tongue associated with flupenthixol induced extrapyramidal symptoms. International Clinical Psycho pharmacology 14 (2): 129–131. 9. Dahlin, P. A., N. E. Van Buskirk, R. W. Novotny, I. R. Hollis, and J. George. 1985. Self-biting with multiple finger amputations following spinal cord injury. Paraplegia 23 (5): 306–318. 10. Robey, K. L., J. F. Reck, K. D. Giacomini, G. Barabas, and G. E. Eddey. 2003. Modes and patterns of self-mutilation

in persons with Lesch-Nyhan disease. Developmental Medicine & Child Neurology 45 (3): 167–171. 11. Shimoyama, T., N. Horie, T. Kato, D. Nasu, and T. Kaneko. 2003. Tourette’s syndrome with rapid deterioration by self-mutilation of the upper lip. Journal of Clinical Pediatric Dentistry 27 (2): 177–180. 12. Keyes, F. A. 1925. Teeth marks on the skin as evidence in establishing identity. Dental Cosmos 67:1165–1167. 13. Sognnaes, R. F., R. D. Rawson, B. M. Gratt, and B. N. Nauyen. 1982. Computer comparison of bite mark patterns in identical twins. Journal of American Dental Association 105:449–452. 14. Barsley, R. E., and D. M. Lancaster. 1987. Measurement of arch widths in a human population: Relation of anticipated bitemarks. Journal of Forensic Sciences 32 (4): 975–982. 15. Dorion, R. B. J. 2007. Bitemark analysis—Part 1 and 2 results. American Academy of Forensic Sciences, San Antonio, TX, Feb. 22, 2007. 16. Dailey, J. C., and C. M. Bowers. 1997. Aging of bitemarks: A literature review. Journal of Forensic Sciences 42 (5): 792–795. 17. Dorion, R. B. J., M. J. Perron, S. Laforte, and M. L. Nielsen. 2006. Bitemark research—Antemortem and postmortem bitemarks. American Academy of Forensic Sciences, Seattle, WA, Feb. 24, 2006. 18. Dorion, R. B. J. 2006. Factors affecting bitemark analysis. American Academy of Forensic Sciences, Seattle, WA, Feb. 24, 2006. 19. Anderson, W. R., and R. P. Hudson. 1976. Self-inflicted bite marks in battered child syndrome. Journal of Forensic Sciences 7:71–74. 20. Sobel, M. N., and J. A. Perper. 1985. Self-inflicted bite mark on the breast of a suicide victim. American Journal of Forensic Medicine and Pathology 6 (4): 336–339.

Patterns, Lesions, and TraumaMimicking Bitemarks Robert B. J. Dorion Richard R. Souviron

19

Contents 19.1 19.2 19.3 19.4

General Consideration Healing Lesions Healed Lesions Patterned Injuries on the Deceased 19.4.1 Passive Compression 19.4.2 Medical Conditions, Treatment, Autopsy Trauma, and Other Objects 19.4.3 Unspecified Marks and Lesions 19.5 Summary References

19.1â•…General Consideration A patterned injury is imprinted when a hard object is pressed into skin over a period of time. The tissue compression may be active or passive, such as lying on an object. The period of time and amount of compression may vary considerably. Great force applied over a short period of time—hitting a person with a baseball bat, for example—is referred to as blunt trauma injury. Certain objects can leave impressions similar to the human dentition. This chapter illustrates patterns, lesions, and trauma that might be misinterpreted as bitemarks and vice versa.

19.2â•…Healing Lesions Fresh compression injuries on the living are analyzed by photographic record supported by the injured party’s statement. Victim testimony is not always available. Children may be too young, or a person may be mentally handicapped, amnesic, unconscious, comatose, or senile, have Alzheimer’s, or be uncooperative. FiguresÂ€19.1–19.3 are patterned injuries for which the victim described the circumstances. The force applied to produce the injury in the first example was insufficient to cause lacerations. The degree of force applied can, in itself, account for the differences in appearance between FiguresÂ€19.1 and 19.2. The potential for misdiagnosing patterned injuries is depicted in FigureÂ€19.3. The class and individual characteristics of the offending instrument, not unlike those of the human dentition, produce repetitive and similar

283 283 284 284 288 294 296 298 299

patterns. The end of a steel pipe produced the lesions on the back. Compare these healing injuries to the bitemarks on the back in the preceding chapter. The lesions on the external genitalia (FigureÂ€ 19.4) of a 17-month-old female were misdiagnosed as human bites that “matched” a suspect dentition. Second opinions obtained from forensic odontologists corrected the misdiagnosis to dermatitis. As previously mentioned, victim testimony is not always available in the living; on the other hand, it is not necessarily reliable. In one example, the alleged victim claimed she was sexually assaulted, cut with a razor blade, burned with a cigar, and bitten on the breast. The victim’s background investigation, not to mention the pattern interpretation, cast doubt on the alleged attack. The alleged cigar burn is actually one resulting from the application of a heated penny on the breast. Lincoln’s outline is observable in the burn (FigureÂ€19.5). In a racially and politically motivated misdeed, the “victim” and a friend wanted to humiliate the intended accused publicly. The other patterned injury on the breast is devoid of class, and individual characteristics typically present in a “fresh” bitemark. There are exceptions to this general statement, however. The lesions adjacent to the penny burn are yellow, green, and blue. The dimension of the alleged bitemark in relationship to the penny impression is somewhat large. Mincer (H. Mincer, personal communication with R. Dorion, 2003) describes the case of a young child with healing crusty patterned injuries on the hands and arms. These burns were produced by an electrical heat hairsetting device known as a “hot comb” (FigureÂ€19.6).

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19.3â•…Healed Lesions

Figure 19.1â•‡ Victim-attested bitemark less than 24 hours old.

Figure 19.2â•‡ Bitemark on the shoulder less than 24 hours old.

Victim and witness accounts often confirm the diagnosis for the cause of the patterned injury. Patterned injuries including bitemarks usually disappear within a few hours or, in more serious cases, within 7–14 days provided the tissue is not amputated. Lacerations and deep compression wounds heal to form scar tissue. While the preceding chapter outlined factors affecting bitemark dynamics, FigureÂ€19.7 illustrates an unusual 1-year-old bitemark. Imagine the potential misdiagnosis in the timing of the injury if excision, transillumination, and histological analysis had not been performed and if the victim had been deceased. In law, scarring may be considered a permanent disability and subject not only to criminal but also to civil litigation under specific circumstances. Healed injuries often create an indistinct pattern that is difficult to analyze. FigureÂ€ 19.8 depicts a victimconfirmed 2-year-old scar from a denture bite. During the altercation, the victim pulled his arm from the biter’s mouth. The laceration was seen, documented, and sutured by a hospital emergency room physician. Within 24 hours the victim returned with an acute infection, swelling, and bacteremia. The lesion was reopened and allowed to drain. A complete upper denture, particularly against lower natural teeth, can produce bitemarks and, under the proper circumstances, tearing or laceration of the skin in addition to serious and even life-threatening infections.

19.4â•…Patterned Injuries on the Deceased Postmortem insect activity is the most common form of patterned injury (FigureÂ€ 19.9) on bodies collected

Figure 19.3â•‡ Patterned injuries on the back resembling human bitemarks.

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Figure 19.5â•‡ Patterned injury from a penny with adjacent

burn.

Figure 19.4â•‡ Dermatitis on the external genitalia of a 17-month-old female.

outdoors. Insect activity begins within minutes of death and is influenced by temperature, humidity, wind, soil, bacteria, body disposition, circumstance, and other factors. In rare cases, it has been misdiagnosed as human bitemarks and, even worse, “matched” to a suspect dentition by the uninformed, unwary, inexperienced investigator. FigureÂ€19.10 displays a case where the investigator “matched” a suspect dentition (upper teeth only) to over 20 patterns thought to be bitemarks. It should be remembered that a single-arch bite is the exception and

not the rule. Moreover, it would be improbable to have a single-arch bite over 20 times on the same body. Insects caused the patterned injuries. Scene investigation and proper autopsy protocol would have promptly resolved the issue. The second most common cause of patterned injuries on the deceased is the result of animal predation. FigureÂ€19.11 illustrates the tragic case of a young child discovered floating in a pond. While the child had obvious signs of predation, some patterns were erroneously interpreted as human bitemarks and matched to a suspect dentition. FigureÂ€ 19.12 illustrates the attempt to match the suspect dentition to the marks on the body. Notice the “match” allegedly coincides with the singlearch bite. Note the desquamation in FigureÂ€19.11. Readers are reminded that a single-arch bite is highly unusual and not the rule. The presence of multiple single-arched bites is even less common. Tissue sectioning is one method used to differentiate between insect activity, surface abrasion, and postmortem artifact (FigureÂ€19.13).

Figure 19.6â•‡ “Hot comb” burn injuries. (Photos courtesy of Dr. Harry Mincer.)

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Figure 19.7â•‡ Documented bitemark over 1 year old.

A pathologist consulted an odontologist for interpretation of the lesions found on an amputated thumb (FigureÂ€19.14) and hand (FigureÂ€19.15) of a strangled male homicide victim. The victim also had perforated eyes and had been disemboweled. The male suspect was the only other prisoner in the cell. It was initially thought that the amputated thumb could have been bitten off. Examination of the tissues revealed “clean” cuts with skin shredding. It was determined that a razor blade was the instrument of amputation rather than the human dentition. The eyes were perforated with pens, and the broken pens were also used in skin mutilation. FigureÂ€19.16 reveals the incised and shredded wounds of the right index finger on the same victim. Presumably, the suspect had insufficient time to amputate the index finger. A pathologist consulted an odontologist for interpretation of the lesions found on the scalp of a male infant homicide victim. The semicircular hemorrhagic patterns under the scalp (FigureÂ€19.17) measÂ�ured almost 4 cm across and trailed off toward one end. The scalp is the only body tissue that is, for all practical purposes, relatively immobile. The result is that the instrument that produces the patterned injury will be more accurately recorded on the scalp than on any other body tissue. Generally speaking, there will be very little distortion of the pattern. In the present case, it would be impossible to produce a single-arch 4-cm-diameter human bite that also records posterior teeth. The unidentified

causative instrument was never recovered. Compare this patterned injury to a similar patterned injury under the scalp in the preceding chapter. An examining pathologist consulted an odontologist regarding a partially excised nipple (FigureÂ€19.18) on a female homicide victim. Other markings were found at the base of the breast and on the areola. The edges of the wound on the nipple were very “clean” and sharp. The continuous incised wound almost encircled the nipple and was perpendicular, not parallel, to the markings on the lateral aspect of the breast (FigureÂ€19.23). The partial excision was credited to a sharp instrument, probably a knife. The causative instrument was never recovered. Examination revealed an amputated nose tip (FigureÂ€ 19.19) in a male homicide victim. Unlike the nose bitemarks described in previous chapters, the edges of the excised tissue are extremely sharp and “clean.” There are no indentations at the edge of the amputated tissue or in the cartilage. The nose tip was removed with a razor blade. Vale (G. Vale, personal communication with R. Dorion, 2003) reported on a patterned injury that appeared remarkably similar to a human bitemark despite the marked differences between the human and canine dentitions (FigureÂ€19.20). The child died as a result of a witnessed dog attack. The forensic odontologist was privileged in this instance to see the injuries on the basis of educational opportunity rather than forensic need. When this photograph was inserted in a bitemark exercise, it was not always correctly identified as an animal bite by the examinees. The 4+ cm distance between opposite teeth in the same arch should be a clue to its nonhuman origin. The case accentuates the need for a thorough and cautious approach in interpreting bitemark evidence. FigureÂ€ 19.21 shows linear, parallel abrasions and contusion measÂ�urÂ�ing approximately 13 mm by 23 mm, anterior to the hairline of the temple. The linear, parallel abrasions were produced by a comb. Patterned injuries on the deceased may or may not have been witnessed. If they were witnessed and revealed exclusively by the perpetrator, a healthy skepticism as to cause and circumstance of the injury is a prudent tactic to adopt. If the event was witnessed and revealed by independent, uninvolved parties, the integrity of the observers and the veracity of the information is less likely to be questioned. FigureÂ€ 19.22 illustrates a patterned injury on the cheek of a female homicide victim. The pathologist initially questioned the unusual starburst pattern (left). The philosophy adopted by most experienced, knowledgeable forensic pathologists is to err on the side of caution, rather than to side with imprudence, negligence, or stupidity. The bitemark hypothesis was eliminated

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Figure 19.8 Scar tissue produced by a complete upper denture.

Figure 19.9 Ant predation.

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Figure 19.10 Multiple patterned injuries from insect bites.

by the odontologist. The second instrument suspected was the base of a Molson beer mug (upper and lower right). Although the base of the beer mug had a central starburst pattern, it also was eliminated. Lastly, another implement—the base of an ashtray—was analyzed and found to be the causative agent. Figure 19.23 reveals contusion on the base of the breast measuring 33 mm end to end that lacks curvature. In addition, the distance between the midpoint of this curvature and the nipple measures 53 mm. The breast is relatively flat (little mass or curvature), minimizing the

possibility for tissue distortion. A photograph taken at the scene of the body disposal revealed a displaced bra. The partially clad female homicide victim was found face down in snow in –20°F weather. The contusions at the base of the breast were attributed to the bra wiring. This case predates DNA analysis. 19.4.1 Passive Compression Pattern development occurs from trauma or passive compression (lying on an object). Figure 19.24 reveals

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Figure 19.11 Body of a young child retrieved from a pond.

Figure 19.12 Alleged bitemark and suspect dentition.

Figure 19.13 Tissue sectioning through surface abrasion. Note the absence of hemorrhaging within the adipose layer.

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Figure 19.15 Distal end of the phalange.

Figure 19.14 Thumb amputation by razor blade.

a patterned injury on the lateral aspect of the abdomen that resembles, in many aspects, a human bitemark. The deceased was recovered lying on the open end of a pipe. Figure 19.25 represents an oval patterned injury found below the right ear lobe of a transvestite homicide victim. There are both class and individual characteristics to the patterned injury. These characteristics are not, however, associated with human dentition. The victim was found lying on a round, braided-metal earring through the pierced ear. Note that the shape of the mark is oval and not round—an excellent example of tissue distortion. Objects can imprint strange patterns, such as the one recorded in Figure 19.26. To the unwary, the pattern might resemble a contused bitemark or a lip print on the inner aspect of a lower leg. The pattern is due to neither. It is a leaf imprint.

Figure 19.16 Incised and shredded wounds of the right index finger.

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Figure 19.17 Hemorrhagic pattern on the underside of the scalp.

Figure 19.18 Partial excision of the nipple.

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Figure 19.19 Partial nose amputation by razor blade.

Figure 19.20 Patterned injury on the arm. (Photo courtesy of Dr. Gerald Vale.)

Figure 19.21 Linear, parallel abrasions on the temple.

Patterns, Lesions, and Trauma-Mimicking Bitemarks

Figure 19.22 Patterned injury with starburst appearance (left) and the base of a beer mug (upper right, lower right).

Figure 19.23 Contusions at the base of the breast.

Figure 19.24 Patterned injury resembling a human bitemark.

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Figure 19.25 Oval pattern injury below the ear caused by an earring.

Figure 19.26 Pattern on the leg resembling a contused bitemark or a lip print. It is neither.

19.4.2 Medical Conditions, Treatment, Autopsy Trauma, and Other Objects Caution should prevail when crime scene photographs are unavailable or the person autopsied has received medical attention. Individuals who receive emergency medical care may present with traumatic lesions and patterns resulting from treatment. Accurate information of events leading to autopsy will prevent patterned injury misinterpretation. (See the preceding chapter for additional examples and related problems.) In the example shown in Figure 19.27, the initial analysis of the patterned injury on the leg ruled out a human bitemark. The pattern was correctly interpreted as the receptacle for a Foley catheter. The literature reports cases of artifactual injury from cardiac defibrillators simulating bitemarks [1]. Vale (G. Vale, personal communication with R. Dorion, 2003) examined the upper left chest of an adult male

Figure 19.27 U-shaped pattern on a leg.

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Figure 19.28â•‡ Patterned injury on the chest wall photographed 24 hours apart. (Photographs courtesy of Dr. Gerald Vale.)

decedent (FigureÂ€19.28, left). The wound was consistent with a human bitemark in some respects: It consisted of two arched injuries facing each other, and each arch had an interrupted pattern suggestive of individual tooth marks. However, the injury had a yellowish-brown color. This was inconsistent with the deep red or blue to purple color usually associated with a recent antemortem contusion on light-colored skin. The odontologist photographed the injury and requested a consultation. When two forensic odontologists saw the injury the following evening, it had changed appearance considerably, with substantial necrosis and sloughing of tissue (FigureÂ€19.28, right). Such dramatic change in a body refrigerated for 24 hours would be quite unusual if this were a contused injury. Since the injury was located in an area where electrocardiograph (EKG) monitor pads are commonly placed, an inquiry was made of the deceased’s emergency medical treatment. Emergency personnel had reportedly placed EKG monitor pads during resuscitation efforts. Careful evaluation showed a faint but visible smooth, curved mark extending downward from the “dental arch” on the right side. This would be incompatible with a bitemark, but compatible with an EKG pad mark. An EKG monitor pad was then compared to the injury. The size was similar, but the pad was circular and the injury was ovoid. This apparent discrepancy was easily reconciled when the location of the injury was taken into account. The axillary region is one of the areas that change shape markedly as the result of body position, such as raising or lowering the arm. This can be demonstrated by drawing a circular mark on one’s own body or by moving the arm in an actual case. It was concluded that the injury was a surface abrasion caused by the removal of the EKG monitor pad rather than a contused injury caused by a human bite. The sloughing may have been related to refrigeration and dehydration of the abraded tissue. A number of wounds and natural diseases share class characteristics with bitemarks and must be ruled out before ascribing a particular patterned injury to

biting. Bernstein (M. Bernstein, personal communication with R. Dorion, 2003) reported that the round paddles of a defibrillator can create a circular patterned injury of compatible size to mimic a bitemark on the torso [1]. These represent burns occurring when inadequate lubricant is applied to the paddles. Similarly, EKG electrodes left in sustained contact with skin can cause an irritation or hypersensitivity reaction that outlines the circular pattern of the contacting ring (FiguresÂ€19.29 and 19.30). If they are suspected, these diagnoses are easily confirmed by medical history. Animal (horse and cow) hoof marks can create rounded bruises resembling bitemarks. Heel marks sustained in stomping injuries can closely resemble

Figure 19.29â•‡ Ring-shaped mark simulating toothless bitemark; created by an EKG electrode left on skin. (Photograph courtesy of Dr. Mark L. Bernstein.)

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Figure 19.30â•‡ Two EKG electrodes having peripheral adhesive rings. (Photograph courtesy of Dr. Mark L. Bernstein.)

Figure 19.31â•‡ Multiple circular ring-like patterned injuries simulating continuous arched bitemarks. (Photograph courtesy of Dr. Mark L. Bernstein.)

bitemarks [2], particularly if the heel has elevations that might simulate tooth marks. Circular jewelry, particularly rings; belt buckles; flashlight handles; and children’s toys can produce circular patterns [3–5] (FiguresÂ€19.31 and 19.32). Some natural diseases produce erosive or erythematous annular or circinate lesions that can be mistaken for bitemarks. Tenia circinata (ringworm), impetigo, erythema multiforme, erythema annulare, granuloma annulare, pityriasis rosea annular lichen planus, contact allergy, urticaria, and herpes are some examples [1,6,7] (FiguresÂ€19.33 and 19.34).

The Southeast Asian custom of cao gio (coining) uses coins heated with oil to mark the skin. The folklore ritual is designed to ward off evil spirits. The heated coins produce ring-like burns. 19.4.3â•…Unspecified Marks and Lesions Postmortem patterned injuries can be caused by a variety of devices. Some are more difficult than others to identify, and some remain unresolved as to the source. FigureÂ€19.35 depicts a pattern on the right shoulder of an exhumed

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Figure 19.32 A ring with peripheral prongs that could create the injuries seen in Figure 19.34. (Photograph courtesy of Dr. Mark L. Bernstein.)

Figure 19.33 Ringworm in right abdomen, simulating a toothless bitemark. (Photograph courtesy of Dr. Mark L. Bernstein.)

embalmed body. The investigator determined the pattern on the shoulder to be a three-tooth single-arch bitemark: two lower bicuspids and a canine. As mentioned several times in this text, single-arch bites are rare. A three-tooth single-arch bite from posterior teeth is improbable. What appears to be tissue excision is in fact demarcation of the

area with a marking pen. The analysis in this case was based solely on an unscaled photographic interpretation without the benefit of bitemark impressions, tissue preservation, transillumination, or histology. Adhering to a bitemark protocol as outlined in this book would have resolved the issue in the scientific manner.

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Figure 19.34 Annular pattern of vesicles caused by herpes simplex virus simulating a bitemark in the neck. (Photograph courtesy of Dr. Mark L. Bernstein.)

Figure 19.35 Shoulder of exhumed body.

Figure 19.36 illustrates several patterned injuries on a decomposing hand. The elderly person, who had lived alone, was found with several bitemarks from a pet cat that had not been fed in several days. The patterned injuries on the hand, however, could not be attributed to the feline dentition and their origin remains unresolved. An experienced forensic pathologist performed an autopsy on a female homicide victim. There was no mention of trauma to the breast area in the autopsy report. Note the presence of dried blood when the photograph in Figure 19.37 was taken. Some time later, a dentist claimed there was a bitemark above the left breast. There were no straight-on photographs of the mark, and the autopsy table drainage holes (circles) were used as a reference to measure the mark. The specimen had not been preserved since no trauma was observed at autopsy.

19.5 Summary Proper determination of the origin of the patterned injury in life or death is critical. In the living, one can usually benefit from the victim’s explanation, whether truthful or not. In death investigations, witness reports may or may not serve to reinforce autopsy findings. Regardless of witness reports, proper autopsy protocol and analysis of the patterned injury will minimize the chances of pattern misdiagnosis. It is important when a patterned injury is analyzed that the investigator obtain scene photographs and be well informed of the circumstances leading to the death. Without full knowledge and other pertinent information relating to the patterned injury, including the medical history, misinterpretation can result.

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Figure 19.36 Patterned injury of unknown cause on the hand.

11.795 mm

24.957 mm

Figure 19.37 Skin imprint above the left breast.

Alan R. Moritz, MD, is credited with the saying: “If the evidence has been properly gathered and preserved, a mistake in interpretation may always be corrected. If the facts required to correct the interpretation are not preserved, a mistake is irreversible.”

References 1. Grey, T. C. 1989. Defibrillator injury suggesting bite mark. American Journal of Forensic Medicine and Pathology 10 (2): 144–145. 2. Harvey, W. 1976. Dental identification and forensic odontology, 88–140. London: Henry Kimpton Publishers.

3. Stimson, P. G., and C. A. Mertz. 1997. Bite mark techniques and terminology. In Forensic dentistry, ed. P. G. Stimson and C. A. Mertz, 137–159. Boca Raton, FL: CRC Press. 4. Clark, D. H. 1992. Practical forensic odontology, 128–205. Oxford: Wright. 5. Rawson, R. D. 1986. Child abuse identification. Canadian Dental Association Journal 14 (3): 21–25. 6. Pillsbury, D. M. 1975. Principles of clinical diagnosis. In Dermatology, ed. S. L. Moschella, D. M. Allsbury, and H. J. Hurley, 189–190. Philadelphia, PA: W. B. Saunders. 7. Habif, T. P. 1985. Clinical dermatology: Color guide to diagnosis and therapy, 86–100. St. Louis, MO: C. V. Mosby.

Research

VI

20

Current Context of Bitemark Analysis and Research Mary A. Bush Peter J. Bush Contents 20.1 NAS Report Overview 20.1.1 Forensic Odontology 20.1.1.1 Victim Identification 20.1.1.2 Bitemark Analysis 20.2 Uniqueness of the Dentition 20.2.1 Resolution 20.2.2 Anthropological Perspective 20.2.3 Representation of the Dentition 20.3 Skin, Distortion, and Detail Transfer 20.3.1 Viscoelasticity 20.3.2 Nonlinearity 20.3.3 Anisotropy 20.3.4 Trends in Bitemarks 20.3.5 Laceration 20.3.6 Profiling a Biter 20.3.7 Correcting for Distortion 20.3.8 Postural Distortion 20.3.9 Tissue Rebound 20.3.10 Implications References

303 304 304 304 306 306 307 307 309 309 310 310 311 311 312 312 313 313 313 315

20.1â•…NAS Report Overview The National Academy of Sciences (NAS) project entitled “Identifying the Needs of the Forensic Science Community” was created by Congress to provide an independent assessment of the present and future resource needs of the forensic science community and to make recommendations in specific areas [1]. These were to maximize use of technology, identify scientific advances, advise on programs to increase numbers of qualified scientists, disseminate best practices for evidence collection and analysis, and examine the role of forensic science in homeland security, interoperability of automated fingerprint systems, and additional issues as determined by the Committee on Identifying the Needs of the Forensic Sciences Community. The study was sponsored by the National Institute of Justice (NIJ) and commenced in September 2006; a final report was originally due in the summer of 2008. In October 2008, the duration was extended and the report, entitled Strengthening Forensic Science in

the United States: A Path Forward, was finally issued February 18, 2009 [1]. Whether by design or not, release of this report in Washington, D.C., coincided with the 2009 annual proceedings of the American Academy of Forensic Sciences in Denver, Colorado. The timing of this was advantageous for those involved in forensic science because it enabled a spirited discussion among those concerned. The report presented 13 recommendations to Congress that, in general, supported creation of a new governing body for forensic sciences, education, and certification of expert witnesses to promote research on validity and bias and to promulgate proficiency testing. While generally following the stated charges, the report made frequent references to writings of recent critics of areas of forensic science such as Saks, Koehler, Cooley, Gianelli, and the Innocence Project. Sectors of forensic science came under critical review, even though the report acknowledged that these specialties had provided reliable evidence and that, due to the system of precedent in courts, such evidence is likely to continue to

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be admitted despite the heralded impact of the Daubert ruling. The scientific gatekeeper role has been handed to the judge. This may seem appropriate, but a judge may not be a scientist. The onus to research, understand, introduce, and critique scientific evidence in the courtroom appears, then, to be on the lawyers. Again, a lawyer is not necessarily a scientist. The progress of science is marked in large part by the acceptance of papers in peerreviewed journals. It would seem that the real gatekeepers are the reviewers of the articles submitted to these scientific journals. Therefore, the issue is not simply a lack of science in pattern evidence (bitemark) expert witness testimony, but also is compounded by a lack of comprehension of the scientific method on the judicial side. In an adversarial system that will take advantage of any perceived shortcomings of an expert witness or his or her methodology and testimony, science appears to become irrelevant in the courtroom, and the result may hinge entirely upon the persuasive abilities of either opposing attorney. There is no doubt that “more and better” research is needed to support or refute the base tenets of certain areas of forensic science. Practitioners of academic research would surely agree that, if implemented, a number of the recommendations outlined in the report would greatly assist the process of obtaining funding support and accomplishing research in forensic science. Clearly, many areas are ripe for additional research (Section 5-11). A principal factor holding back research has been lack of recognition of the importance of this research and the concomitant lack of funding for it. With respect to forensic odontology, other than small society grants, the sole funding agency for research has been the NIJ, but the report acknowledges the potential lack of impartiality of this agency because of its association with law enforcement. Ideally, as the report recommends, an independent agency should oversee future funding directions for the various forensic specialties. If criticism is to be leveled at branches of forensic science because of lack of studies, criticism could also be leveled at the lack of awareness of policy makers and grant authorities for funding relevant studies. The academic community would welcome and support implementation of impartial peer review because that is the basic process by which science advances. Of particular interest to those in the academic community is the analysis given in Section 2 of the report specifically regarding research funding (Section 2-13). Comparison of research funding levels is provided and an analysis of funding for research projects by the NIJ in 2007 is given in Box 2-2 of the report (Section 2-15). It is noted that 21 projects were funded in 2007 but that none

of the open questions about common forensic science methods were addressed in those projects. A conclusion is that the level of support is well short of what is necessary (Section 2-18). Also stated is that the development of DNA analysis resulted from substantial and steady federal support for academic research (Section 3-20). The conclusions of the report with respect to forensic odontology have been widely anticipated. Current research directions have been largely oriented toward addressing the issues laid out in the report, and a series of relevant papers has been accepted for publication in the Journal of Forensic Sciences. 20.1.1 Forensic Odontology The authors of the NAS report found the NIJ categorization of forensic science disciplines to be useful [1–3]. Forensic odontology is not seen on this list and presumably exists somewhere within the categories of medicolegal death investigation (victim identification) and impression evidence (bitemark analysis). 20.1.1.1 Victim Identification At the core of victim identification is a pattern recognition process that may involve visual comparison of radiographic evidence to determine if antemortem records match postmortem records. Perhaps because this evidence is typically not presented in the courtroom and therefore not subject to cross-examination, the NAS authors did not feel this to be controversial and the report did not include mention of this aspect of forensic dentistry. If one were to be logical, one would have to validate dental identification also. It is possible that several of the sources of bias and error exist in this process as with other forms of pattern evidence interpretation. Notably, the NAS authors appeared to feel more comfortable when evidence analysis moved from expert opinion to scientific laboratory analysis. A paradigm shift has already taken place in the victim identification area of forensic dentistry. Progressing from simply recognizing the presence of a given restoration in a radiographic set, an established database has enabled us to ask the question of what type of material comprises the restoration. Thus, when dental materials are present, victim identification analysis can progress to the laboratory and be aided by established scientific methods [2–6]. 20.1.1.2 Bitemark Analysis In the section of the report outlining the principles of science and interpreting scientific data, mention is made of the reliable inference of knowledge from uncertain information and protections against bias and overstatement (“going beyond the facts”; Sections 4-1 and 4-2).

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The report authors state that adherence to scientific principles can assure success for the forensic scientist in these endeavors. This certainly applies to bitemark analysis; however, as outlined later, there are special concerns in this field that do not occur in other forms of impression evidence analysis. The principal criticisms leveled at bitemark analysis in the NAS report are restated as follows:

unaltered or excised. However, the questions of differences in anatomy and dermal structure compared to human skin have not been resolved. In general, however, comparative pigskin bitemark studies have resulted in dentition and bite matches with a lower rate than with bites recorded in plastic substrates [7]. To date, the best research substrate available is human cadaver skin, which has relevant biomechanical and anatomical properties [10]. Examination of the seven points enumerated previously follows:

1. The uniqueness of the human dentition has not been scientifically established. 2. Transfer of a pattern, if unique, to skin has not been established. a. Ability to analyze and interpret scope of distortion in skin has not been demonstrated. b. Effect of distortion on comparison techniques has not been quantified. 3. Accuracy of skin as registration material has not been established (Section 5-37). 4. Standard for evidentiary value has not been established. 5. Effect of healing process is not understood (Section 5-35). 6. No large population studies have been performed (Section 5-37). 7. Rarely are comparisons made between the bitemark and a number of models (Section 5-36). In several places in the NAS report, reference is made to a quotation: “There is no evident reason why rigorous, systematic research would be infeasible” (e.g., Section 3-20). This may apply to fingerprint or tool mark examination, but in bitemark analysis there are limitations to what research can feasibly be performed on the living or deceased human. The conditions in which a bitemark may be inflicted—for example, a violent altercation or child abuse situation—cannot be experimentally replicated. Furthermore, human subject review limits live subject experimentation in which pain tolerance or pain threshold levels are exceeded. Using existing casework as educational material is potentially at risk because the case as resolved in the courtroom may not reflect the actual circumstances of bitemark infliction, and the certainty of a gold standard (knowing the actual identity of the biter) is not available unless DNA is present at the bite site. Because living human skin has limits of study, a substitute must be found that possesses the viscoelastic biomechanical properties of human skin. Although a number of studies have been conducted using bite substrates with plastic properties (wax, Styrofoam, etc.), it is clear that these materials represent inadequate models [7–9]. Animal models using pigskin have also been utilized, whether they are anatomically

1. Uniqueness of the dentition That the human dentition is unique is under question. A 1984 paper by Rawson et al. used a single point to delineate x and y positions and angulation of the six anterior teeth. Rawson used the product rule and assumption of uniform position distributions to arrive at probabilities of uniqueness. A recent paper revisited this method, but with consideration of correlation and nonuniform position distribution [11]. Positive dental matches were found in the data sets studied, indicating that, given the measure ment parameters used, the human dentition is not unique. This is further discussed later. 2. Transfer of a pattern, if unique, to skin has not been established. a. Ability to analyze and interpret scope of distortion in skin has not been demonstrated. b. Effect of distortion on comparison techniques has not been quantified. A recent study compared 100 models to bites in human skin. A match rate within this population was determined [12]. 3. Accuracy of skin as registration material has not been established. These issues are discussed later. 4. Standard for evidentiary value has not been established. A paper by Pretty and Bowers established a scale of evidentiary value, but as of the time of this writing, there has been no formal adoption of this method by the American Board of Forensic Odontology (ABFO) [13]. 5. Effect of healing process specifically for bitemarks is not well understood. See Chapter 15 regarding pathology. A paper by Dailey and Bowers reviewed knowledge current at the time on the color of healing wounds other than bitemarks, a subject about which Davis (in this textbook) cautions [14].

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6. No large population studies have been performed (Section 5-37). While small sample studies have been performed regarding the issue of dental uniqueness, no large-scale study has been performed to date. Unfortunately, these small population studies either used flawed methodology or lack a formal statistical approach. 7. Rarely are comparisons made between the bitemark and a number of models. This is true in general casework. As discussed later, Marx is an example of this, but is questionable concerning methodology. Recent empirical research has emphasized the importance and relevance of population comparisons [12]. In short, most of the areas of deficiency identified in the NAS report have been addressed or are under active study. The impact of the NAS report in the courtroom has yet to be determined, but there can be no doubt that the scientific studies referenced here will be introduced as part of the evidentiary submission process.

20.2 Uniqueness of the Dentition Is the human dentition unique? The NAS report, in its criticism of bitemark analysis, lists the concern that “the uniqueness of the human dentition has not been scientifically established” [1]. This may be interpreted to indicate that efforts should be made to establish a level of uniqueness of the human dentition. Such an approach may be in error. In order to examine this question, it is first important to explore the concept of uniqueness and then place it in the context of bitemark analysis. For bitemark analysis, the concept of uniqueness under ideal circumstances incorporates six to eight teeth from each jaw. This should not be confused with uniqueness in dental identification where there are potentially 32 teeth, with various treatment options for each of five surfaces. It has been argued that individualization—that is, an object is stated to be different from every other object in its class—is unattainable. This viewpoint has been advanced by a number of writers from the legal profession and has been termed the individualization fallacy. According to this approach, uniqueness cannot be proven because it is impossible to measure every dentition in existence and also everyone that has ever existed. In the critical writings of Saks and Koehler, the argument is made that individualization is an abstraction and that demonstration of uniqueness is unattainable [15–17]. Faigman discusses the same concept in his text, which Gianelli and Beecher-Monas similarly

reiterate. Cole’s treatise entirely dismisses uniqueness as a viable descriptor, but intimates a possible way forward by briefly discussing resolution [18]. From a simplistic perspective, it may seem to make sense to state that uniqueness is an empty claim. However, writing from a nonscientific viewpoint, it is not surprising that the preceding authors failed to consider or are unaware of the concept of measurement resolution. 20.2.1 Resolution In the scientific measurement world, resolution is expressed as a dimension that represents the smallest object measurable by a given method of measurement. Resolution is said to be high when that dimension is small. Thus, the concept of scale is relevant. It is possible today to measure objects on the Earth from space with a spatial resolution of better than 1 m. Applied to dentition, using scanning electron microscopy (SEM), it is possible to measure detail with a resolution of better than 10 nm. On that scale, surely the dentition can be described as unique because the minutia of chips, fractures, and individual tooth structure will clearly distinguish one dentition from another? In fingerprint analysis, the detail compared is bordering on the microscopic. Magnification is obviously useful in resolving detail, but there is a maximum magnification above which no useful additional information is gained. In bitemark analysis, there are two considerations. One is measurement of the dentition and the other is the ability to resolve transferred detail to skin. Accurate replicas of the dentition that can be measured by methods with very high spatial resolution, such as confocal laser microscopy or SEM, can be created. Details can indeed be visualized on the dentition that, without doubt, represent individualization features. Similarly, the surface of the skin can be replicated with submicron resolution. However, the question remains as to whether detail from a dentition transfers and is retained on a viscoelastic medium such as skin. Magnification of detail by SEM, for example, might rarely be useful in bitemark analysis. Distortion is inevitable in a bitemark due to the skin’s properties. This reduces measurement resolution and compromises the ability to recognize individualizing features. Although precise measurements of the dentition are possible, at best only class and individual characteristics might be measurable in the skin. The situation worsens when only a diffuse bruise remains in the skin. It might be more logical to view the human dentition with regard to its similarity to another dentition rather than to claim uniqueness since the meas urement resolution in skin is greatly reduced. Therefore,

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looking for a match rate based on a resolution threshold may be a more practical approach.

treatment is further utilized, one may expect this population to increase.

20.2.2 Anthropological Perspective

20.2.3 Representation of the Dentition

The human dentition by definition represents a biological form that belongs to a single species. It is logical to conceive that there is a finite range of shape space into which all humans will fit. This has been borne out by metric studies that have measured the means and ranges of the human dentition [19]. The biological functions of mastication, breathing, and speaking require a certain arrangement of the teeth that in the majority of the population will be similar. Anthropologists have studied dentition for over 100 years, and the scientific subdiscipline of dental anthropology is well established. Examination of the literature from this field reveals that, based on nonmetric traits, the human dentition has historically exhibited consistent similarities. From an anthropological perspective, it has been observed that a given human race has a shared biological shape form that acts as an identifier. This approach has been used to associate members of races based on similarities of dental traits. A textbook devoted to one such study describes a database of 30,000 dentitions, among which 23 nonmetric traits were compared [20]. According to that text, dental traits were consistent and reliable enough to place an individual in a cultural group. This may be true historically; however, due to modern cultural assimilation, one might expect to see the differences disappear between dentitions in a modern population. In other words, from an anthropological perspective, as assimilation progresses, a majority of extant humans will have similar dentitions according to assessment of traits. Studies that investigate how frequently a malalignment pattern may be seen in a population have also been performed [21]. Dental crowding, especially in the lower anterior region, is frequently encountered and may be classified into discrete common patterns. In a study of 7,000 individuals who were 15–50 years of age, it was shown that 21.9% of the population had a zero mandibular incisor irregularity index; 30% had clinically significant irregularity and 15% had severe irregularity [22]. Thus, on the basis of the 2000 U.S. census, there are approximately 56 million individuals in the United States who are 15–50 years of age with clinical crowding and approximately 24 million with severe crowding [22]. These numbers suggest a large population with the potential for similar patterns. Furthermore, following orthodontic treatment, the anterior dental pattern becomes much more homologous, creating a large group of similarly aligned dentitions. As orthodontic

The de facto practical approach that has developed in forensic odontology grew from hand tracings of dentitions through photocopied acetates to scanned dentitions and computer-generated overlays of the 12 anterior teeth. These techniques may be considered to be methods to produce oval-shaped representations of the anterior teeth that may be overlaid onto a twodimensional representation of the bitemark. In using this method, there is an implicit assumption that individualizing detail is captured in these oval shapes. No matter how such representations are produced, it is undeniable that there are inaccuracies in representation of the dentition because a three-dimensional object is being rendered in two dimensions. In production of these overlays, the concept of measurement resolution appears to have been lost. Assume, for example, that a flatbed scanner is used to produce an image of a model at 300 dpi. Each pixel size is around 85 µm and thus the resolution of measurement is just that—85 µm. If such an overlay is placed on an image of a diffuse bruise, is the shape assumed to match with the same resolution? Furthermore, placing such an overlay on a photograph of a bitemark may be very convincing to a jury, but if 100 overlays of similar dentitions are placed on a bitemark, it quickly becomes apparent that there can be a significant match rate [12]. Question 7 of the NAS report, comparing large numbers of dentitions to a bitemark (a dental lineup), becomes relevant. Herein lies the historical and fundamental problem with bitemark analysis: overstatement of certainty based on lack of consideration of similarity of human dentitions. When one is presented with analysis of a bitemark in a situation in which the perpetrator could belong to an open population, it would seem logical to pose the question of what the match rate in that population might be. In the seminal 1975 California case, People v. Marx, the forensic odontologists appeared to do that by comparing the bitemark to 710 randomly sorted dentitions. Eighteen dentitions were found to have “gross similarities” to the bitemark, but when they were impressed into wax, discrepancies that excluded those models were noted. Vale et al. concluded that the probability of another dentition matching the suspect was less than 1 in 710 [23]. This example raises several issues. The use of a nonviscoelastic test substrate to rule out possible matches brings up the question of how comparisons were made and the resolution or level of detail noted. It is known today that impression of the dentition into skin produces

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bitemark distortion that reduces measurement resolution [12]. In the preceding example, did the odontologists discover a match rate (2.5%) that was relevant to the case? That the odontologists in the Marx case performed a “dental line up” may be considered part of a thorough approach. Notably, however, there has been little mention of repeating this in subsequent cases, even though the Marx case was the first of its kind in California. It is as if, by performing the empirical comparison once, the question was resolved. In Faigman’s words, “Marx pried open the door for bitemark identification. Having done so it became the admission ticket for … many subsequent cases” [17]. The concept of looking for dental matches in an open population has not been revisited until recently [10,12,24,25]. Rather, the literature has documented attempts to support the presupposed conclusion of dental uniqueness [19,26,27]. Rawson and others’ much cited 1984 paper claimed that “human dentition is unique beyond reasonable doubt” based on the use of the product rule to calculate tooth positions. That work has been recently revisited with consideration of correlation and nonuniform distribution, resulting in determination of significant match rates in open populations [11]—contrary to the claim of Rawson et al. Consideration of how the comparisons were made in Marx and the metric methods used by Rawson leads to the question of what exactly constitutes a match. In Marx, presumably a direct visual comparison was used. Rawson used a single measured center point of the incisal edge of each tooth, along with rotation angle. Bitemark comparisons today may typically involve placement of a hollow volume overlay on a 1:1 sized image of the bitemark—again, using the eye to gauge the fit. The pitfalls encountered with the latter method were emphasized in a recent paper in which overlays of dentitions known not to have made the bite fit the bitemark image better that the known biter [12]. The current comparison method has evolved without the large-scale metric studies that might have established dentition match rates in an open population. For example, if one were to assume an intercanine distance in the dentition of 25 mm and encounter distortion of 27% in a bitemark, then there will be a 6.75-mm difference in this measurement between the dentition and bitemark [12]. Clearly, this does not reflect accurate transfer of dimension. In this example, it becomes of no consequence that the resolution of measurement of the dentition was 85 µm in production of an overlay when the error produced by distortion in the skin is an order of magnitude greater. Having established a match rate in an open population using specified measurement resolution, when error

due to distortion is factored (reducing resolution), the number of possible matches obviously increases. In addition, when a diffuse bruise is measured, exactly where does the measurement begin and end? This brings into question methodology of measurement of a bitemark and underlines consideration of resolution of measure ments. What is the scientific basis in placing a hollow volume overlay over a bruise and claiming a visual fit? Rawson and others’ 1984 study was an attempt to confirm the unique nature of the human dentition statistically using a large population [26]. In this study, a strong claim was made that the large number of possible tooth positions (states) observed in the data set indicated that the “human dentition is unique beyond any reasonable doubt.” It was argued that the very large number of states observed preclude any possibility of matches to a given dentition, given their measurement parameters. There are four significant weaknesses to this argument: 1. It was not reported whether any specimens under the protocol actually matched. 2. It was assumed that specimens are equally or uniformly distributed over the possible tooth positions and that there was no clustering of tooth positions into common patterns of dentition. 3. The effect of correlation of dental traits was not considered (i.e., the concept that one tooth is usually in close proximity to the next). 4. The product rule was employed, without incorporating any measure of correlation, to make the claim that the number of possible combinations of human tooth positions for six anterior lower teeth in the lower jaw alone is on the order of 6.08 × 1012, or effectively infinite. Rawson used a single point to describe a tooth in x, y, and angle, with a measurement resolution of ±1 mm and ±0.5°. In a study that replicated Rawson’s methods, Bush et al.11 examined two dental populations to determine numbers of matches and match rates, with consideration of nonuniform distributions and correlation. Two separate sets of scanned dental models (n = 172 and n = 344) were measured and statistically tested to determine match rates. In the respective data sets, 7 and 16 matches of the six anterior lower teeth were found, giving a match rate of around 4%. The number of matches increased geometrically with database size because the number of possible comparisons of n specimens increases with the square of n (the number of possible comparisons is n(n – 1)/2). When a small number of dentitions in a closed population is compared, the likelihood of a match

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is low, but still possible. The implication of this study is that, given a large enough population, the next dentition compared to the database will be highly likely to match an existing sample. Thus, statements concerning dental uniqueness with respect to bitemark analysis in an open population are unsupportable. In 2007, Kieser et al. were the first to publish the use of a relatively new method to describe and compare dentition shape: geometric morphometric analysis. This method has been successfully employed to describe biological form and allows the use of multivariate statistical methods for visualization of factors contributing to shape variation in a biological system [27]. In their study, they placed points, or landmarks, to delineate the mesiodistal widths of the teeth. These data points were extracted and the effects of size and rotation were removed while preserving shape information. Kieser et al. compared the six anterior teeth in 33 maxillas and 49 mandibles, which had been orthodontically treated, and concluded that the small variation in shape seen supported the notion of dental uniqueness. However, as noted previously, as a dental database grows, the likelihood of a match increases. The small sample size of Kieser et al. cannot be considered representative enough to prove uniqueness of the human dentition. Of note, however, is the fact that all of the aforementioned studies on the six anterior teeth are two dimensional. Acknowledgment of the fact that human dentitions are similar and may indeed match (in six anterior teeth) changes the language of the basis of bitemark analysis. The statement that human dentition is unique is not justified. A qualified statement of the first premise is indicated:

From a bitemark perspective, skin is a notoriously poor recording medium. It is an intricate tissue that possesses viscoelastic, anisotropic, and nonlinear properties. This complexity is further exacerbated by the fact that these properties not only vary from person to person, but also can differ from site to site on any given body. There are two main layers of the skin: the epidermis and the dermis. The prime load-bearing properties of whole skin are determined by the dermis, and the bio mechanical properties of skin are largely determined by the architecture of this layer [31,32]. The thickness of skin and underlying substrate are determinants as to how the whole will respond to stress.

The human dentition fits within the boundaries dictated by our species. Given a large enough population, it is almost certain that a dental match for six anterior teeth will be found. Even in a closed population, there is a chance that two individuals will be identical within defined measurement parameters.

20.3 Skin, Distortion, and Detail Transfer Considering that bitemark analysis involves inspection of wounds in skin, it is remarkable that the literature in bitemark analysis has almost totally ignored the properties and nature of the skin. The papers that have considered skin have been simple in nature and raised more questions than answers [28–30]. Few studies have been reported in the last two decades. Therefore, it would seem relevant in this text to review some basic properties of the dermis and to consider the literature from mature scientific fields that have been concerned with skin.

20.3.1 Viscoelasticity The dermis consists principally of elastin fibers, collagen, fiber bundles, and ground substance. Elastin fibers ranging from 0.5 to 0.8 µm in width and up to 50 µm in length are interwoven among the collagen fibers and are composed of 4% of fat-free dry weight [31]. They exist in a wavy, irregular network and begin to uncoil and stretch when stress is exerted on the skin. Elastin fibers possess a rubber-like nature for high extensibility and are responsible for the elastic component of the overall viscoelasticity of skin. The elastin fibers allow for normal movement of the body, uncoiling and recoiling readily. The skin in most areas of the body is easily stretched and will resume its original dimensions quickly once the forces are removed. If the stress exerted on the skin continues to increase, elastin fibers will exceed their elastic limit. When this occurs, the collagen fibers begin to extend. The collagen fiber network comprises 75–77% of the fat-free dry weight of skin. Each fiber varies from 1 to 40 µm [31]. They possess high tensile strength but low extensibility. Therefore, they can absorb a high level of stress, but do not elongate very much. Collagen also exists in a wavy, irregular, coiled network in skin. Once the fibers start to uncoil and straighten, the tissue starts to become more viscous because these fibers are not elastic. Collagen fibers only stretch about 5–6% when fully extended [31]. Once this occurs, skin can no longer elongate, resulting in absorption of stress until the rupture point. The ground substance is an amorphous gel filling spaces between collagen and elastin fibers. It is mainly composed of mucopolysaccarides [31]. As the collagen is extended under high stress, the ground substance is expressed into the surrounding tissue. This process creates the indentations seen when teeth impress the skin. As time passes, the ground substance regains its original position, erasing the indentations and causing the rebound seen in bitemarks.

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20.3.2â•…Nonlinearity A characteristic of viscoelastic materials is a nonlinear response to stress [30–35]. The nonlinear response of skin can be illustrated in a J-shaped stress–strain curve (FigureÂ€20.1). Because the shape of the curve is in a “J” rather than straight, the load deformation of skin is said to be nonlinear. In this curve, the X-axis represents strain, or percent elongation. The Y-axis represents stress or pressure. The curve is divided into three phases; each phase represents the reactions and response of the elastin, collagen, and ground substance. Phase I illustrates the elastic phase of skin. In this phase, it is the elastin fibers that extend at low stresses. The curve depicts an elongation of skin at around 30% in the elastic phase. If the stress is increased, the collagen fibers begin to uncoil and stretch, thus placing the curve into phase II. The second phase begins in the elbow of the curve and represents increasing stiffness (increase in viscosity). During normal body movements, the skin can be subjected to strains corresponding to this portion of the curve. During this phase, the collagen fibers are starting to unravel and straighten. The stiffening of skin that is seen in this phase is attributed to the collagen fibers becoming aligned and resisting extension. The waviness of the collagen fibers (prior to stretching) is variable; many have different degrees of original crimp, so some become straightened before others. As skin is stressed through the second phase, there is progressive resistance

8

I

II

III

Stress MPa

7 6 5 4 3 2 1 20

40 Elongation %

60

Figure 20.1â•‡ A typical J-shaped stress–strain curve illus-

trating the nonlinear response of skin to stress. In phase I, long-range elongation is possible at low stress. As the stress is maintained, skin becomes increasingly viscous and elongation becomes limited. (Reprinted with permission. Bush, M. A. et al. 2009. Journal of Forensic Sciences 54 (1): 167–176.)

to further extension due to the inextensible properties of collagen. The third phase of the curve is almost linear. Once all the collagen fibers are straight, any further stretch of the skin is dependent on the extensibility of the collagen fibers themselves, which is very low (5–6%). Here, the skin is essentially hard and is not deforming anymore. It will continue to absorb the stress until the rupture point. The main mechanical role of collagen is to impart tensile strength [31]. The principal change with age with regard to this curve is the amount of elongation possible in the first phase of the curve. Elastin is lost with age; therefore, skin can decrease to about 20% elongation in the first phase with old age [31]. The slope of the curve remains the same, allowing some to speculate that while extensibility decreases, tensile strength increases. Skin tension lines also affect the appearance of this curve, shifting the entire curve to the left in higher skin tension areas. 20.3.3â•…A nisotropy Anisotropy means that skin has different properties in different directions [36–42]. Skin exists in a state of pretension, with the tension greater in one direction than in another. This varies according to any given anatomical location. In addition, variation exists if the person is thin or fat and standing or lying down. Tension in skin can be relaxed by bending joints [41]. Skin is more extensible when it is perpendicular to tension lines and less extensible when it is parallel to them. Anisotropy determines how quickly skin can exceed its elastic limit and enter the viscous stage at any given direction. Descriptions of tension lines have appeared in the literature since the mid-1800s, with over 36 tension line descriptions; the most widely known are Langer lines [39,40]. Hence, tension lines are frequently referred to as Langer lines. The classic Langer experiment illustrated this finding. Cadaver skin was punctured with a round instrument [39]. The resulting wounds were not round in shape but elliptical. The axis of the ellipses will point in the direction that originally had the most tension. Simple pinch tests can also illustrate this feature because skin will be easier to pinch in the perpendicular direction and more difficult in the parallel direction (FigureÂ€20.2). It is the properties of skin that contribute to the distortion seen within a bitemark. Understanding skin fundamentals with regard to biomechanical properties would seem to be essential for the forensic odontologist; however, there are caveats as to how that knowledge might be used.

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311

Figure 20.2â•‡ Pinching of the skin in the parallel direction to tension lines; skin is much harder to take hold of in this direction (left). Pinching of skin perpendicular to tension lines; skin is much easier to gather in this direction (center). Pinching in the parallel direction but with the arm bent, thus relaxing the inherent tension; skin becomes easier to grip (right).

20.3.4â•…Trends in Bitemarks Skin properties are complex. Though they contribute to the distortion observed and though some overall trends can be recognized, it is of the utmost importance to emphasize that knowledge of these properties cannot be used for prediction of distortion. Nor do they allow for any attempt at correction of the distortion. The forensic odontologist should simply recognize that distortion occurs and that it can range in magnitude. In experimental bites on cadaver skin, it was found that, the tightness of the tissue corresponded to the trend in the resulting dental pattern, which was to decrease the mesial to distal width of each individual tooth, decrease the intercanine distance, and make the angles of rotation steeper between teeth (FigureÂ€ 20.3) [10]. This was particularly evident when the bite was created parallel to skin tension lines because the tissue was inherently tight in this direction. When the skin was looser, the opposite was seen; as the mesial to distal widths increased, the intercanine distance increased and the angle of rotation between teeth became flatter (FigureÂ€20.4, left) [10]. Although these general trends may be described, the magnitude of the distortion and whether it complied with these trends cannot be anticipated. Research has shown that bites inflicted with the same dentition produced patterns that were all different, with varying degrees of difference (intra-arch as well as interarch) from the original dentition [10]. This empirical study demonstrated distortion up to 80% in tooth angulation, 29% in mesial to distal dimensions, and 27% in intercanine distance in bitemarks inflicted from a single dentition on cadaver skin. In addition, there were dramatic differences in bitemark appearance according to location of the bitemark on the body and subsequent movement [10]. This was a laboratory study in which static bites were inflicted on cadavers without the dynamic momentum that might be present in an altercation. Distortion may be far more significant in such conditions. These observations suggest that it

Figure 20.3â•‡ Bite created parallel to tension lines. The

overall arch form is constricted. (Reprinted with permission. Bush, M. A. et al. 2009. Journal of Forensic Sciences 54 (1): 167–176.)

is impossible to anticipate and correct for distortion in skin (FigureÂ€20.5) [24]. 20.3.5â•…Laceration Laceration of skin appears to be highly dependent on the variables of tooth sharpness, movement, and underlying tissue type (anatomical location), such as areas of the body where skin is tightly stretched over bone (for

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 20.4â•‡ Bites created perpendicular (left) and parallel (right) to tension lines. Both bites were created with the same dentition. The overall bitemark arch form is elongated (left). (Reprinted with permission. Bush, M. A. et al. 2009. Journal of Forensic Sciences 54 (1): 167–176.)

example, the scalp). In these tighter tissue areas, elongation of skin is very limited and it will enter phase III of the stress–strain curve almost immediately. Laceration may be more likely with these types of tissues. Avulsion may be more likely in body areas such as the tongue, ear, nose, or chin, where teeth can take hold of the object and bite through. Research has shown that, while possible, laceration is difficult to effect in human skin even at forces higher than those that the anterior segment of the human dentition is capable of administering [24]. The reason for this can be illustrated in the example in FigureÂ€20.5 (center and left) and FigureÂ€ 20.6. The numbers in the photos correspond to the load that was used to inflict the bites. Load is simply the kilogram weight used to inflict the bites. The maximum load capability of the volunteer was 20 kg. This corresponds to a force of 196 N, where force is mass times acceleration and is reported in newtons (N). Maximal force capability in the anterior segment of the human dentition has been reported to be 90–370 N [43–45]. Stress is force per unit area and is reported in megapascals (MPa). Thus, stress is obtained by dividing force by the surface area of the biting dentition. Notice in FigureÂ€20.5 (center and left) that while the arch shape seems to be varied, the amount of damage to the tissue appears to be the same (macroscopically from postmortem bites). Even at loads that are much greater than the maximum achievable in a human dentition (68 kg equates to 666 N), the amount of damage to the tissue, in this example, appears similar. The reason for this can be seen in FigureÂ€20.6. When the load is converted to stress and plotted on the curve, it can be seen that, at a load of 30 kg, the curve now is starting to enter

the straight portion; no more elongation is possible and all the skin is doing is absorbing the stress until the rupture point, which can be quite high. Therefore, at loads greater than 30 kg, the indentation amount and tissue damage look the same. At a load of 16 kg, the location on the curve corresponds to a point in which some elongation is still possible; therefore, these indentations do not look the same as the ones created with the higher loads. The variation in arch shape is attributable to anisotropy (skin tension lines). 20.3.6â•…Profiling a Biter Since some distortion is inevitable and some is considerable, one should be prudent in profiling or predicting the dental appearance of a biter based upon a presumptive pattern seen in the skin. An empirical study showed marked deviation from the biter’s dentition 38% of the time (FigureÂ€ 20.7). The potential bias generated from this practice may steer an investigation in ways that may exclude entire populations or, worse yet, lead to the conviction of an innocent person. Features noted during examination of the dentition may not have accurately transferred to the skin and vice versa [25]. Stipulating in advance could lead to inaccurate perpetrator identification and can easily lead to bias. 20.3.7â•…Correcting for Distortion As stated before, it is inadvisable to attempt any type of correction for distortion. Due to skin tension lines, the degree of distortion will not be uniform within a bitemark. There will be inter- as well as intra-arch differences

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313

Opening diameter was 40 mm 8

All 3 bites are 25 kg

I

II

III

Stress MPa

7

30 kg

6 5

20 kg

4

16 kg

3 Opening diameter was 40 mm 40 kg

30 kg 50 kg

2 1

5 kg 20

40 Elongation %

60

Figure 20.6â•‡ At 16 kg of load, the tissue has not fully elongated. A small amount of elongation is still possible. Once the skin has been subjected to 30 kg, elongation is essentially complete. Load will be absorbed until the rupture point. (Reprinted with permission. Bush, M. A. et al. 2010. Journal of Forensic Sciences 55 (1): 71–76.)

16 kgs

68 kgs

30 kgs

inflicted [10,29]. Since tension lines can be altered by the bending of joints and skin can be stretched or retracted depending on movement, postural distortion can have a large influence on the resultant pattern left in skin. The amount of distortion can be seen in FigureÂ€20.8 (left), in which the bite was inflicted with the arm straight at the side. On the right side of FigureÂ€20.8, the arm has been extended over the head. Notice the overall change in the bite pattern.

Figure 20.5â•‡ All three bites were created with the same

load of 25 kg (force: 196 N) (upper). The opening diameter was 40 mm. Notice the difference in overall arch shape between the bites. The opening diameter was 40 mm but the load was varied (center). Again, notice the overall difference in arch shape, but the amount of indentation of the bites looks the same. Three bites created at three varying loads (left). The one on the left is not indented as much as the other two. The reason for this can be seen in Figure 20.6. (Reprinted with permission. Bush, M. A. et al. 2010. Journal of Forensic Sciences 55 (1): 71–76.)

and the magnitude of these differences can be considerable [25]. They are not predictable due to the complex variables associated with the skin. One cannot accurately predict from bitemark observation alone which area might have decreased in size and which may have increased. 20.3.8â•…Postural Distortion Movement of the victim can also cause another type of distortion known as postural distortion, which occurs when a bitemark is photographed with the victim in a position different from that in which the bite was

20.3.9â•…Tissue Rebound Indentation rebound is a result of the ground substance regaining position after application of stress. This may be described as a hysteresis effect. Indentation rebound in the living can be influenced by wounding factors—a vital response to tissue insult. Indentations can disappear in a brief amount of time (under 2 minutes) in the living due to edema of the area from the injury, rather than simple rebound of the indentations. 20.3.10â•…Implications In the light of establishment of dental match rates and empirical research on human skin, it would seem that careful consideration should be given to expression of certainty in bitemark analysis. To put it plainly, recent studies and consideration of the limits of human biological shape point to the conclusion that two- and threedimensional alignment of six anterior teeth is probably not unique within measÂ�ureÂ�ment resolution limits [46]. FigureÂ€20.9 illustrates an example of two matching anterior dentitions from an open population of 500. Based

314

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 20.7 Though the bite was created with a missing tooth, it appears as if the bitemark is not missing any teeth (left). (Reprinted with permission, Journal of Forensic Sciences 55 (1): 71–76.) Notice the deviation in rotation of the central incisor in the bitemark from the dentition that caused it (red arrow) (right). (Reprinted with permission. Miller, R. G. et al. 2009. Journal of Forensic Sciences 54 (4): 909.)

Figure 20.8 The bite was inflicted with the arm straight at the side (left). The bitemark is outlined in black for ease of

viewing; biter’s overlay is in blue. Movement of the arm over the head (right). Notice the alteration to the bite pattern. (Both photos reprinted with permission. Bush, M. A. et al. 2009. Journal of Forensic Sciences 54 (1): 167–176.)

on placement of 60 landmarks on the incisal edges of the anterior teeth in three dimensions, these dentitions have a shape similarity that is within measurement error, as established by repeated measures. Any individual characteristics present in the dentition may or may not be present in the skin and, if so, may be significantly distorted. Furthermore, current studies have shown that each time teeth engage skin, a unique event occurs. This fact complicates bitemark research [10,12,24,25]. This, coupled with the inability to reproduce actual crime scene parameters, emphasizes

the difficulty of performing research in this area. Establishment of error rates in bitemark casework may therefore be beyond reach. Questions raised by the NAS report are being addressed, but the results illustrate the complexity of the topic rather than providing a simple validation. In comparison to other pattern evidence fields, the forensic odontologist should understand that there have been few scientific studies performed and that it is wise to be prepared with the best current knowledge that science can provide. The authors of this chapter believe that bitemark

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315

Figure 20.9 Representation of three-dimensional models of two dentitions in which the six anterior teeth were found to have the same three-dimensional shape, based on measu rement error determined by repeated measu rement.

evidence can be compelling and of significant evidentiary value under certain circumstances; however, caution is recommended in every aspect of bitemark analysis.

References 1. Committee on Identifying the Needs of the Forensic Sciences Community, National Research Council. 2009. Strengthening forensic science in the United States: A path forward. Washington, D.C.: National Academies Press. 2. Bush, M. A., R. G. Miller, A. Norrlander, and P. J. Bush. 2008. Analytical survey of restorative resins by SEM/ EDS and XRF: Databases for forensic purposes. Journal of Forensic Sciences 53 (2): 419-425. 3. Bonnavilla, J., M. A. Bush, P. J. Bush, and E. Pantera. 2008. Identification of incinerated root canal filling materials after exposure to high heat incineration Journal of Forensic Sciences 53 (2): 412–418. 4. Bush, M. A., R. G. Miller, H. Fagin, and P. J. Bush. 2007. The role of dental materials in situations involving high temperatures: A review article in forensic odontology. Minerva Medicolegale 127 (2): 97–105. 5. Bush, M. A., R. G. Miller, J. A. Prutzman-Pfieffer, and P. J. Bush. 2007. Identification through XRF analysis of dental restorative resin materials: A comprehensive study of noncremated, cremated, and processed cremated individuals. Journal of Forensic Sciences 52 (1): 157–165. 6. Bush, M. A., R. Miller, P. Bush. 2006. Detection and classification of composite resins in incinerated teeth for forensic purposes. Journal of Forensic Sciences 51 (3): 636–642. 7. Blackwell, S. A., R. V. Taylor, I. Gordon, C. L. Ogleby, T. Tanijiri, M. Yoshino, M. R. Donald, and J. G. Clement. 2007. 3-D imaging and quantitative comparison of human dentitions and simulated bite marks. International Journal of Legal Medicine 121 (1): 9–17.

8. Dorion, R. B. J. 1989. Styrofoam as an impression material. Proceedings of the American Academy of Forensic Sciences, Feb. 13–18, 1989, Las Vegas, NV. 9. Dorion, R. B. J. 2001. Bitemark project 2000—Objectivity. Proceedings of the American Academy of Forensic Sciences, Feb. 19–24, 2001, Seattle, WA. 10. Bush, M. A., R. G. Miller, P. J. Bush, and R. B. J. Dorion. 2009. Biomechanical factors in human dermal bitemarks in a cadaver model. Journal of Forensic Sciences 54 (1): 167–176. 11. Bush, M. A., P. J. Bush, and H. D. Sheets. 2010. Statistical evidence for the similarity of the human dentition. Journal of Forensic Sciences [e-pub ahead of print]. 12. Miller, R. G., P. J. Bush, R. B. J. Dorion, and M. A. Bush. 2009. Uniqueness of the dentition as impressed in human skin: A cadaver model. Journal of Forensic Sciences 54 (4): 909. 13. Pretty, I. A. 2007. Development and validation of a human bitemark severity and significance scale. Journal of Forensic Sciences 52 (3): 687–691. 14. Dailey, J. C., and C. M. Bowers. 1997. Aging of bitemarks: A literature review. Journal of Forensic Sciences 42 (5): 792–795. 15. Saks, M. J., and J. J. Koehler. 2008. The individualization fallacy in forensic science evidence. Vanderbilt Literature Review 61:199–219. 16. Saks, M. J., and J. J. Koehler. 2005. The coming paradigm shift in forensic identification science. Science 309 (5736): 892–895. 17. Faigman, D. L., M. J. Saks, J. Sanders, D. H. Kaye, and E. K. Cheng. 2006. Modern scientific evidence: Forensics. Tampa, FL: Thompson West. 18. Cole, S. A. 2009. Forensics without uniqueness, conclusions without individualization: The new epistemology of forensic identification. Law, Probability and Risk July: 1–23.

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19. Bernitz, H., W. F. van Heerden, T. Solheim, and J. H. Owen. 2006. A technique to capture, analyze, and quantify anterior teeth rotations for application in court cases involving tooth marks. Journal of Forensic Sciences 51 (3): 624–629. 20. Scott, R. G., and C. G. Turner. 1977. The anthropology of modern human teeth: Dental morphology and its variation in recent human populations. Cambridge, England: Cambridge University Press. 21. Shigenobu, N., M. Hisano, S. Shima, N. Matsubara, and K. Soma. 2007. Patterns of dental crowding in the lower arch and contributing factors. A statistical study. Angle Orthodontist 77 (2): 303–310. 22. Buschang, P. H., and J. D. Shulman. 2003. Incisor crowding in untreated persons 15–50 years of age: United States, 1988–1994. Angle Orthodontist 73 (5): 502. 23. Vale, G. L., G. N. Felando, R. F. Sognnaes, and T. T. Noguchi. 1976. Unusual three-dimensional bite mark evidence in a homicide case. Journal of Forensic Sciences 21 (3): 11. 24. Bush, M. A., K. Thorsrud, R. G. Miller, R. B. J. Dorion, and P. J. Bush. 2010. The response of skin to applied stress: Investigation of bitemark distortion in a cadaver model. Journal of Forensic Sciences 55 (1): 71–76. 25. Bush, M. A., H. I. Cooper, and R. B. J. Dorion. 2010. Inquiry into the scientific basis of bitemark profiling and arbitrary distortion compensation. Journal of Forensic Sciences 55:976–983. 26. Rawson, R. D., R. K. Ommen, G. Kinard, J. Johnson, and A. Yfantis. 1984. Statistical evidence for the individuality of the human dentition. Journal of Forensic Sciences 29 (1): 245–253. 27. Kieser, J. A., V. Bernal, J. N. Waddell, and S. Raju. 2007. The uniqueness of the human anterior dentition: A geometric morphometric analysis. Journal of Forensic Sciences 52 (3): 671–677. 28. Barbenel, J. C., and J. H. Evans. 1974. Bite marks in skin— Mechanical factors. Journal of Forensic Science Society 14 (3): 235–238. 29. Sheasby, D. R., and D. G. MacDonald. 2001. A forensic classification of distortion in human bite marks. Forensic Science International 122 (1): 75–78. 30. DeVore, D. T. 1971. Bite marks for identification? A preliminary report. Medicine Science Law 11 (3): 144–145. 31. Wilkes, G. L., I. A. Brown, and R. H. Wildnauer. 1973. The biomechanical properties of skin. Critical Reviews in Bioengineering 1 (4): 453–495. 32. Millington, P. F., and R. Wilkinson. 1983. Skin. Cambridge, England: Cambridge University Press.

33. Oxlund, H., J. Manschot, and A. Viidik. 1988. The role of elastin in the mechanical properties of skin. Journal of Biomechanics 21 (3): 213–218. 34. Edwards, C., and R. Marks. 1995. Evaluation of biomechanical properties of human skin. Clinical Dermatology 13 (4): 375–380. 35. Hendriks, F. M. 2001. Mechanical behavior of human skin in vivo: A literature review. Koninklijke Philips Electronics N.V., Nat. Lab. Unclassified report, 1–46. 36. Byard, R. W., A. Gehl, and M. Tsokos. 2005. Skin tension and cleavage lines (Langer’s lines) causing distortion of ante- and postmortem wound morphology. International Journal of Legal Medicine 119 (4): 226–230. 37. Reihsner, R., and E. J. Menzel. 1996. On the orthogonal anisotropy of human skin as a function of anatomical region. Connective Tissue Research 34 (2): 145–160. 38. Ridge, M. D., and V. Wright. 1966. The directional effects of skin. A bio-engineering study of skin with particular reference to Langer’s lines. Journal of Investigative Dermatology 46 (4): 341–346. 39. Langer, K. 1978. On the anatomy and physiology of the skin. I. The cleavability of the cutis. Translated from Langer, K. 1861. Zur anatomie und physiologie der haut. I. Uber die spaltbarkeit der cutis. Sitzungsbericht der mathematisch-naturwissenschaftlichen classe der kaiserlichen academie der wissenschaften. British Journal of Plastic Surgery 31 (1): 3–8. 40. Langer, K. 1978. On the anatomy and physiology of the skin: II. Skin tension (1862), trans. T. Gibson. British Journal of Plastic Surgery 31 (1): 8–13. 41. Borges, A. F. 1989. Relaxed skin tension lines. Dermatology Clinics 7 (1): 169–177. 42. Wilhelmi, B. J., S. J. Blackwell, and L. G. Phillips. 1999. Langer’s lines: To use or not to use. Plastic and Reconstructive Surgery 104 (1): 208–214. 43. Paphangkorakit, J., and J. W. Osborn. 1998. Effects on human maximum bite force of biting on a softer or harder object. Archives of Oral Biology 43 (11): 833–839. 44. Mioche, L., and M. A. Peyron. 1995. Bite force displayed during assessment of hardness in various texture contexts. Archives of Oral Biology 40 (5): 415–423. 45. Paphangkorakit, J., and J. W. Osborn. 1997. The effect of pressure on a maximum incisal bite force in man. Archives of Oral Biology 42 (1): 11–17. 46. Bush, M. A., P. J. Bush, and H. D. Sheets. 2010. Description of the human dentition using three-dimensional landmarks: An investigation of similarity and match rates. Proceedings of the American Academy of Forensic Sciences, Feb. 22–27, 2010, Seattle, WA.

Research, Emerging Technologies, and Recent Developments Robert B. J. Dorion

21

Contents 21.1 21.2 21.3 21.4

History from 1970 Bitemark Cases in Quebec ABFO Bitemark Workshops Dorion, Bitemark, 2000 21.4.1 Scoring and Results 21.4.2 Comments on the Selection of Preorthodontic Models 21.4.3 Comments on the Selection of Postorthodontic Models 21.5 Georget, 2003 21.6 NIJ and Tom’s Toolbox, 2006 21.7 Avon, 2007 21.8 The NAS Report, 2009 21.8.1 AAFS Position Statement, 2009 21.8.2 ABFO Response and Guidelines, 2010 21.9 SUNY, 2006– 21.10 McGill University, 2004– 21.10.1 Extracellular Fluid Expulsion 21.10.2 Clothing 21.10.3 Hair Presence and Removal 21.10.4 Bite Slippage 21.10.5 Overlapping/Superimposed Bites 21.10.6 Disproportionate Dimensional Distortion 21.10.7 Bitemark Profiling 21.10.8 Lingual Markings 21.10.9 Disappearing Teeth 21.10.10 Bitemark in the Presence of Other Trauma 21.10.11 Autopsy Artifacts 21.10.12 Ears and Cartilage 21.10.13 Nipples 21.10.14 Complementary Information 21.10.15 Bitemarks Containing Fewer Than 12 Teeth 21.10.16 Bitemark Orientation 21.10.17 One-Sided Bite 21.10.18 Muscle Perforation: Three Dimensional 21.10.19 Contusion within a Bitemark 21.10.20 Antemortem versus Postmortem Bitemarks 21.10.21 Lividity 21.10.22 Freezing 21.11 Bitemark Comparison 21.12 Summary References

317

318 320 320 323 323 323 324 324 324 326 327 327 328 328 328 328 328 330 331 331 331 332 333 335 335 335 335 336 336 336 336 337 337 337 339 339 340 341 346 428

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“Reported” Bitemark Cases in U.S. 120 100 80 60 40 20 0

1950–9

1960–9

1970–9

1980–9

1990–9

Figure 21.1 This figure illustrates the dramatic increase

in the use of bitemark evidence in U.S. courts from the 1970s forward. (Figure courtesy of Dr. Gerald L. Vale.)

21.1 History from 1970 Starting in the 1970s, there was a dramatic increase in the use of bitemark evidence in U.S. courts. For many years, Pitluck has painstakingly compiled and updated a listing of reported bitemark cases at the appellate level. Figure 21.1 depicts information derived from Pitluck’s data and graphically illustrates the increase in reported cases from 1950 to 1999. In brief, bitemark evidence made its formal appearance in U.S. courts in the 1950s, gained significant momentum in the 1970s, and then experienced a relative explosion into the legal arena in the 1980s and 1990s. This time-related assessment is not precise because, among other things, the time lag between the date of the crime and the date of the report is highly variable and tends to be lengthy. For example, in the case of People v. Marx, the crime occurred in 1974 and the appellate decision was reported in 1975. However, in the Milone case, the crime occurred in 1972, and reports of the higher courts appeared in 1976, 1992, and 1994 (G. L. Vale, personal communication, 2004). A glance of the American Academy of Forensic Sciences’ 27th annual meeting in Chicago in February 1975 shows 12 papers in odontology with two odontology plenary sessions. The three noteworthy papers on bitemark evidence included lectures by Dr. Miles Standish on the methods of developing bitemark evidence, Dr. Richard Souviron on the dental role in child abuse, and Dr. Curtis Mertz on a survey of impression materials for forensic odontology. The plenary sessions included the topic of dental evidence in crimes against children, moderated by Dr. Lowell Levine, and the oral

manifestation and legal aspects of child abuse, moderated by Drs. Stanley Schwartz and Edward Woolridge. The report on bitemark evidence [1] was presented at the American Academy of Forensic Sciences (AAFS) odontology section in 1977 and was published for the first time in the first edition of this book. It might be of interest from a historical perspective to examine the report in order to appraise the current situation. The committee’s mandate was to assess and develop criteria for bitemark investigation. A three-part questionnaire was sent to all members of the odontology section as well as to selected individuals throughout the world with known experience with bitemarks. There were 31 respondents. Among the non-American respondents were R. B. J. Dorion, G. Johanson, S. Kogon, J. Purves, K. Suzuki, G. C. Swann, W. Harvey, S. Keiser-Nielsen, and P. R. Van Ostenberg. Warren Harvey’s classic textbook, Dental Identifi cation & Forensic Odontology, had just been published in 1976 [2]. The five chapters dealing with bitemark evidence concerned bites and bitemarks; experimental human bitemarks; characteristics of individual teeth and identification from bitemarks—preliminary statistical data; saliva in forensic odontology; and the preparation of models of teeth and bitemarks in food and on bodies. A handwritten letter from Warren Harvey’s wife can best express the importance of the AAFS survey: June 21, 1976 Dear Dr. Dorion, My husband Dr. Warren Harvey was a member of the American Academy of Forensic Sciences and received your questionnaire at the beginning of April. You may not have heard that he died on May 7th. He was busy until his death answering the questionnaire in longhand and in great detail, as you will see. I have done my best to decipher his notes, and have typed them out (I am not, as you will see, a trained typist) and am sending them to you in case they are of interest! I know it is long past the date they were asked for. This was the last academic task my husband completed before he died, and it gave him great satisfaction to try and answer to the best of his ability. Sincerely yours, Sheila Harvey

Dr. Harvey’s nine-page typewritten letter ends with the following: As I am writing in bed recovering from a coronary, will you please accept my apologies for the format. I have had to adopt doctors’ orders to answer the longest exam

Research, Emerging Technologies, and Recent Developments paper I’ve ever had. I wish I was 20 years younger and could start to work with you if you would have me!

The questionnaire, divided into three parts, related solely to the contributors’ personal experiences in dealing with bitemark evidence. The first part analyzed personal experience by bitemark type: animal, human, and false or pseudobites, and by category of bitemarks on live or deceased individuals (FigureÂ€ 21.2). It then analyzed the status of the victim and suspect, whether alive or deceased. The distribution by bitemark type and country is seen in FigureÂ€21.3. The reported U.S. statistics are overstated because more than one expert investigated the same case. In the Malone case (1976), for example, there were four odontologists: two for the prosecution and two for the defense.

319

The criteria for discerning between bitemarks of human and animal origin were divided into categories of subjective and objective analysis. The related court experience in these cases was among the 44 questions to part 1. FigureÂ€ 21.4 categorizes the number of cases ending in court with or without opposition. FigureÂ€21.5 categorizes the number of court cases involving human bitemarks by country. Part 2 of the questionnaire included 21 questions relating to bitemarks on inanimate objects. The responses included bitemarks on cheese, apple, sandwich, candy, chewing gum, wood, leather jacket, and baked clay. Of 13 cases reported, only one went to court. The information received was insufficient to form a reliable conclusion for evaluating procedural and technical methods that were and should be used.

Bitemarks on Live Individuals: Number of Cases

Bitemarks on the Deceased: Number of Cases

Bitemarks of animal origin

128

â•⁄ 63

Bitemarks of human origin

â•⁄ 46

267

“False” bitemarks

â•⁄â•⁄ 7

â•⁄ 22

Total number of bitemark cases

181

352

Figure 21.2â•‡ Bitemark distribution by type. Bitemarks on Live Individuals (No. Cases) Bitemarks of animal origin

1

Bitemarks of human origin

1

1

1

2

114

5

7

â•⁄ 30

2

â•⁄â•⁄ 4

1

9

148

10

3

2

2

7

18

313

8

2

Sweden (1)

â•⁄ 21

Wales (1)

â•⁄ 1

United States (22)

2

Canada (4)

7

Japan (1)

232

Denmark (1)

15

England (1)

7

1

Sweden (1)

2

â•⁄ 60

Wales (1)

8

2

â•⁄ 2

United States (22)

1

10

Canada (4)

Country (experts)

2

Japan (1)

Total number of cases

Denmark (1)

2

England (1)

False bitemarks

Bitemarks on Deceased Individuals (No. Cases)

Figure 21.3â•‡ Bitemark distribution by country. Total Experience

Other Than U.S. Experience

U.S. Experience

Number of cases ending in court (duplication)

77

34

43

Forensic dentist opposed views in court

12

â•⁄ 2

10

Forensic dentist corroborated views in court

29

16

13

Total number of cases

57

37

20

Figure 21.4â•‡ Bitemark distribution by court case.

320

Bitemark Evidence: A Color Atlas and Text, 2nd Edition Country

Bitemarks on Human Tissue

England

â•⁄ 4

Denmark

â•⁄ 0

Japan

15

Canada

â•⁄ 8

United States

20

Wales

â•⁄ 7

Sweden

â•⁄ 3

Figure 21.5â•‡ Bitemark distribution by court case and country by 1976.

Lastly, part 3 of the questionnaire asked contributors to suggest the three most important recommendations they could make to the committee. As a result of the recommendations, psychiatric and psychological profiling by dentists based on the bitemark was abandoned. It was thought that such profiling was not within the realm of the forensic dentist’s knowledge and expertise and also that the factors affecting bitemark dynamics were so numerous as to render questionable any profiling based upon the bitemark alone. For example, what would be the psychiatric or psychological profiling attributed to drag marks produced by the dentition? In one case, the drag marks can be produced as a result of slippage and closure of the dental arches against tissue; in another, they can be the result of the pulling action of the victim and/or the biter. If the forensic dentist cannot definitely attribute the specific action used to produce the bitemark, how can he or she attribute a psychological or psychiatric profile to the action? To this author’s knowledge, the first and last article on psychiatric bitemark profiling by a psychiatrist appeared in the American Academy of Forensic Sciences journal in 1979 [3]. Use of the word “sucking” in bitemark interpretation also became restricted in use. While it is clear that sucking can be an activity associated with bitemarks, it is not possible categorically to differentiate the presence of a sucking injury (commonly known as a “hickey”) from other forms of trauma. One clue might be the presence of salivary DNA that can be associated to a nonspecific bruise lacking the class and individual characteristics of a bitemark. On the other hand, that same bruise could result from other trauma and someone spitting at that location on the victim’s body.

21.2â•…Bitemark Cases in Quebec This author itemized by category the forensic dental cases in which he acted as a consultant for the Laboratoire

de Sciences Judiciaires et de Médecine Légale between 1973 and 1995 [4]. These did not include private cases or consultations within and outside the province. Formal dental identification accounted for 84.48% of cases; nonforensic dental identification (historic or cemetery specimens), 4.94%; crime scene recovered dental specimens, 5.25%; and bitemarks, 5.33%. The 328 bitemarks were categorized as follows: 207 human, 73 animal, 15 self-inflicted, 8 on inanimate objects, 11 of unknown or unidentifiable origin, and 14 nonbitemarks. There would appear to be a higher number of cases and a higher number of bitemarks per case in Quebec than in other jurisdictions, as reported by two colleagues [5,6]. Does this mean that there are more biters in this population or that the pathologists are better diagnosticians? During a lecture a number of years ago in a midsize American city, the lone medical examiner with over 15 years of experience claimed: “We have never had a bitemark in this jurisdiction.” How many did he fail to recognize? Failure to diagnose is probably the number one problem, closely followed by failure to consult. Both are professionally unacceptable. Since 1973, this author has been consulted in over 3,600 forensic cases at the Laboratoire de Sciences Judiciaires et de Médecine Légale, as of May 2010.

21.3â•…A BFO Bitemark Workshops The American Academy of Forensic Sciences (AAFS) odontology section, the American Society of Forensic Odontology (ASFO), and the American Board of ForenÂ� sic Odontology (ABFO) are all involved in continÂ�uing education for their members. The latter also provides workshops for applicants interested in pursuing certification. Its board realized that, in addition to assessing a person’s competency, it has the responsibility of setting standards and guidelines for the practice of forensic dentistry. This includes setting guidelines not only for the identification of the deceased but also for the recognition and analysis of bitemarks. To this end, the board eventually established the Research Committee, the Standards, Methods, and Procedures Committee, the Bitemark Evidence and Patterned Injury Committee, and the Certification and Examination Committee. The results of the AAFS odontology section bitemark survey in 1974 and that of the ABFO in 1983 were used as the basis for organizing bitemark workshops (FigureÂ€21.6) that ultimately set standards and guidelines; the first was held in 1984. Bitemark workshop 1 established general guidelines regarding all aspects of bitemark evidence. Workshop 2 established guidelines and standards in regard to bitemark terminology and methodology, in

Research, Emerging Technologies, and Recent Developments Year

Place

Chair

Purpose

1984

Anaheim

Krauss Vale

General bitemark guidelines Scoring system negated in 1988

1994

San Antonio

Bell

Methodology, terminology (1995); scientific principle

1997

New York

Bell Dorion

Review of literature, injury analysis Report writing

1999

Orlando

Bell

Educational exercise on quality and evidentiary value of bitemarks, not proficiency testing

2002

Atlanta

Bell

Teach nondiplomates guidelines and methodology

2003

Chicago

Dial

Teach nondiplomates guidelines and methodology

2006

Seattle

Dial

Teach nondiplomates guidelines and methodology

2008

Washington

Bell

Teach nondiplomates terminology, evidentiary value, report writing

321

Figure 21.6 ABFO bitemark workshops from 1984 to 2008.

addition to a review of the scientific principles. Workshop 3 reviewed past and current literature in regard to bitemark evidence and analysis. It made an attempt to establish guidelines in regard to injury analysis in relation to amount and quality of evidence collected and to establish bitemark report writing guidelines. Workshop 4 reviewed and updated bitemark evidence collection in regard to the dentition responsible for the bite injury. The workshop made practical use of previously established guidelines and standards in regard to bitemark case analysis and methods of comparison and guidelines for bitemark forensic report writing. The purpose was to determine if the amount and the quality of bitemark evidence would have any impact on the participants’ ability to associate the available evidence with the suspects’ dentition. Some persons have misinterpreted the purpose of and the statistical analysis derived from the workshop. The ABFO’s board of directors authorized a position paper regarding the workshop in 2003 [7]. The 32 participating diplomates in workshop 4 were given varying amounts of information on four bitemark cases along with seven sets of dental models. Each case included differing amounts and types of evidence available for analysis. The workshop was designed as an educational exercise and not as a proficiency examination. It was meant to establish a consistency of agreement among examiners when they were confronted with cases of varying levels of evidentiary value. A proficiency examination is designed to assess competency within a discipline. Proficiency tests are administered to verify whether the examinee has maintained sufficient minimum skills to perform the tasks at hand. The examiners were asked to analyze each case and to answer the following questions:

• What is the degree of certainty that this injury is a bitemark (range of values: indeterminable, incompatible, unlikely, possible, probable, reasonable certainty, or definite)? • What is the forensic value of the case (range of values: case has high forensic value and could support a reasonable certainty/very probable identification as well as an exclusionary finding; case has medium forensic value and could support a possible or “consistent with” type of identification as well as an exclusionary finding; case has low forensic value and would not support a linking type of finding but could be used for an exclusionary finding; or case has no forensic value and should not be used in an investigation either to link or exclude)? • What is the link between the bitemark and the noted dentition (range of values: nondiagnostic, inconclusive, incompatible, improbable, possible, probable, or reasonable medical certainty)? Several limitations were associated with the cases and procedures utilized in this workshop, including: • Three of the four bitemark cases were not witnessed or confessed to. They relied on the submitter’s opinion to establish the baseline conclusions for each case. It is possible that the submitter may have been incorrect in his or her original analysis of the case. • A number of the participants were allowed to take part even though they did not submit required reports. This resulted in inconsistencies in the analysis of the workshop results. • Based on conversations with the participants and the results obtained, it was apparent that a

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

number of the participants did not fully understand the values they were entering. This lack of understanding resulted in incompatible answers to the three preceding questions. • It was also obvious that many of the participants did not treat these cases as seriously as they would have actual cases in terms of thoroughness and time spent in analysis. Following the tabulation of participants’ answers from the workshop, there was a desire by some of the diplomates to have a statistical analysis conducted on the participants’ responses. The thinking was that this could bolster the credibility of bitemark analysis. Following completion of the statistical analysis, the executive committee and the board of directors voted to publish the report. Kristopher Arheart and Iain Pretty, who had accomplished the statistical analysis for the board, were asked to write that report. Realizing the limitations in the construction of the workshop and wishing to avoid the appearance of concealing its results, the executive committee and directors of the ABFO voted to submit the findings of the workshop to a refereed scientific journal for publication. The motivation was also to demonstrate the proactive position the ABFO has taken in the field of bitemark analysis, pointing out that, in spite of the best of intentions, problems can occur in the construction of a workshop of this type, which would preclude obtaining valid statistics. The ABFO initially submitted the write-up of the workshop results to the Journal of Forensic Sciences for publication. The article was ultimately rejected because the journal’s editorial reviewers were of the opinion that the workshop was not constructed appropriately for a statistical analysis. It was the reviewers’ opinion that a statistical analysis of this type of workshop would be erroneous because the participants were actually evaluating the subjective determination of an original examiner in three out of the four cases examined. Such an objection would imply that any statistical analysis of this workshop would not be valid. Remaining convinced that the information obtained from this workshop should be published, in spite of questionable validity of the statistical analysis, the board pursued submission of the article to another refereed journal. Arheart and Pretty subsequently published the results of this workshop in Forensic Science International. Arheart and Pretty concluded that the results of this workshop survey indicate that “analysis of bitemark evidence is a relatively accurate procedure among experienced forensic odontologists when the results are

examined in combination.” However, the authors also noted that this study involved only four cases and that “these cases are not representative of the range of cases encountered in the real world.” They further stated: Therefore, the findings of this study generalize only to cases having moderate to high forensic value. In future studies, a larger number of cases covering a wide range of forensic values should be used to increase the generalization or cross-section and to facilitate the use of individual receiver operating characteristic (ROC) analyses [60].

Because of the limitations of the case material in bitemark workshop 4, one cannot draw accurate statistical conclusions that would be applicable to actual casework. The analysis of this workshop indicates a need for further study of the agreement among examiners confronted with varying degrees of evidentiary value in bitemark analysis. It is the responsibility of each individual examiner to determine if sufficient evidence exists to go forward with a meaningful bitemark analysis. The board also recognized that the most experienced persons in bitemark evidence were board members, and that the board had a responsibility to educate nondiplomates seeking continuing education credits ultimately to apply for board eligibility. To this end, workshops 5–12 were for nondiplomates: • Workshop 5 (2002) was held in Atlanta under the chairmanship of Dr. Gary Bell and had guidelines and methodology as themes. • Workshop 6 (2003) was held in Chicago and workshop 7 (2006) in Seattle; they were chaired by Dr. Richard Dial and had the 2002 workshop’s theme. • Workshop 8 was held in Washington, D.C. (2008) under Dr. Bell with terminology, evidentiary value, and report writing as themes. • Workshop 9, on abuse, was in Denver (2009) under Drs. Jack Kenney, John McDowell, and Duane Spencer. • Workshops 10 and 11 were held in Seattle (2010) under Drs. Jim Lewis and Peter Loomis for age estimation and dental identification, respectively. • Workshop 12, on bitemarks, was held in Chicago (2011) and chaired by Dr. Bryan Chrz. Diplomates may attend these workshops for continuing education credit; nondiplomates receive credit for a bitemark case requirement for board eligibility.

Research, Emerging Technologies, and Recent Developments

21.4 Dorion, Bitemark, 2000 With the millennium came the era of bitemark research, beginning with the summer project of 2000 at the Laboratoire de Sciences Judiciaires et de Médecine Légale. The first edition of this text reported on this project, so the current edition summarizes it. The project objectives were to • Compare bitemarks from preorthodontic and postorthodontic dental casts • Investigate whether the then recently pioneered method of digital examination and comparison of bitemarks to dental casts could be performed by a person with no forensic experience • Investigate whether comparison was possible without access to the actual casts or to the bitemarks (photographs only) • Investigate the objectivity of the method • Investigate possible additions to the existing standards for the bitemark analysis • Study the effects that orthodontic therapy has in distinguishing one bitemark from another What happens when the dentition is modified by orthodontic treatment to obtain a “perfect” dentition? Orthodontics is a field in dentistry that alters individual physical features by leveling, reorienting, and realigning the dentition. How do the dental changes influence the observer’s ability to identify the biter correctly? Can software programs assist in evaluating the bitemarks made by the “ideal” dentition? Can software programs contribute to observer objectivity? Can subjectivity be eliminated? A bitemark contains information about its creator, but that information may be incompletely transferred to the substrate or indecipherable. The medium itself can be problematic. Transferring three-dimensional dental characteristics to skin and interpreting them in a twodimensional form (photographs or digitized images) can lead to additional potential loss of information. Lastly, the third dimension, depth, is often lost as a result of skin and underlying muscle elasticity. Bitemark analysis is both a qualitative and a quantitative evaluation. The qualitative component refers to the accuracy and readability of the transferred information from dentition to substrate. The more accurate and readable it is, the better the quality of the bitemark will be. The quantitative component refers to how many dental characteristics are transferred to the substrate. Are there 2 or 12 teeth in the bitemark?

323

Roberts, a novice to forensic odontology who carried out the project, claimed that the technique of digital comparison of dentition bitemarks was exceedingly easy to comprehend and to perform [8]. The method did not assume extensive knowledge of odontology or even computer literacy, but computer skills and some knowledge of the program were helpful in expediting the comparison process. The step-by-step guide given was more than adequate to allow a layman to compare bitemarks to dental casts. 21.4.1 Scoring and Results For many of the dentitions, Roberts began the comparison without the frontal view, but found it more difficult to eliminate bitemarks from the initial list without the use of this view. When the frontal view was used, the time taken for the identification was significantly reduced. The positive identification of the preorthodontic models with the respective bitemarks took approximately 21 hours, while the postorthodontic comparison took approximately 63 hours—triple the amount of time spent in comparison. The preorthodontic comparison success rate was 100% (50 commitments to positive matches; 50 correct matches). This is an incredible success rate, especially for a novice who knows little of bitemark evidence and who was restricted to the use of digitized images only. The postorthodontic comparison success rate was 78% (41 commitments to positive matches out of 50, with one mismatch). Each correct positive match was attributed 2%; in the case of a mismatch, 2% was deducted. The reasoning behind the 2% deduction for mismatches was to discourage guesswork on the part of the examinee. Did committing to 41 out of the 50 cases suggest that the bitemarks resembled each other too closely or that the dentitions are no longer unique? Roberts claims that, given only the digitized images of the dentitions and the bitemarks, he could not commit to a positive identification for the remaining comparisons. 21.4.2 Comments on the Selection of Preorthodontic Models Roberts was asked to comment on the degree of difficulty of the project upon completion. The process of comparing preorthodontic models to the bitemarks was a relatively easy task that took approximately 3 days. Postorthodontic cases took about 9 days of comparison. Primarily the preorthodontic casts were easier to

324

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

distinguish among themselves, rendering the initial method of comparison as one of exclusion. The initial focus was on (1) tooth position and rotations within the same arch (i.e., the angle and relation between the two central incisors, followed by the relation of the laterals and their angular position in the arch and the adjacent teeth, and so on), and (2) the presence of a central diastema—often an obvious point on both casts and bites (whether one exists or not). These points were normally enough to reach a reasonable conclusion; then, additional details confirmed the identity. The line of thinking adopted by the observer was to choose a set of models, mentally note the major discriminatory factors in the arch alignment, and then compare those factors to the bitemarks by eliminating the obvious impossibilities. The process excluded many bites, leaving a handful of possibilities. The elimination process would eventually lead to a single possibility. The frontal views of the casts were not really necessary, but occasionally the extra points of consistency helped in a final decision. In only a handful of cases was it necessary to apply details of intercanine width and/or individual tooth characteristics to reach a conclusion. 21.4.3 Comments on the Selection of Postorthodontic Models The postorthodontic models and the bitemark comparisons were a completely different story, according to Roberts. Initially, mental notes on tooth angulation were useful in a few cases, but on the whole the eye was unable to distinguish differences in tooth position because the arches were too neatly aligned. The frontal views of the casts were incredibly important in identifying the biter since the variations of the incisal horizontal relationship proved to be of paramount importance. In fact, it was found that noting the horizontal level of the teeth in both arches and the expectation of prominence in the bitemark was a prime exclusionary factor in the selection process. For example, if the canines of the lower arch were very prominent, one might expect to find them in the bitemark. Whether both arches coincided with the bite in the comparison was very valuable. Intercanine width was the next point for which exclusion could be made. On the whole, intercanine width was highly variable, but many casts fell within similar parameters. When it came down to selecting one bite over another, more details were needed. This included tooth width and minute dental details such as tooth chipping and notching of the incisal edges. The presence of drag marks in the bitemark was a good point of reference. All these points—the horizontal relationships of the incisal edges,

Preorthodontic • Angulations (relation to arch/other teeth) • Positions (relation to arch/other teeth) • Level of teeth • Intercanine width • Individual tooth characteristics

Figure 21.7 Preorthodontic criteria. Postorthodontic • Level of teeth • Individual tooth characteristics • Intercanine widths • Positions (relation to arch/other teeth) • Angulations (relation to arch/other teeth)

Figure 21.8 Postorthodontic criteria.

notching, intercanine width, tooth widths, chips, and occasional tooth angulations (still present in some postorthodontic cases)—helped in matching biter to bitemark. The points of reference in descending order of usefulness are outlined in Figures 21.7 and 21.8.

21.5 Georget, 2003 On November 5, 2003, Dr. Charles Georget defended his PhD thesis, “A Contribution to the Study of Human Bite Marks on Humans Skin,” at the University of Nancy, Lorraine, France [104]. For part of his thesis, he worked on two live subjects and maintained that bitemark depressions are specific to each subject, depending on muscular tonicity, elasticity, tissue thickness and type, and the exerted pressure.

21.6 NIJ and Tom’s Toolbox, 2006 No one has yet seriously challenged the uniqueness of the human dentition. The factors that contribute to the uniqueness include the three-dimensional spatial relationship between crowns, roots, trabecular patterns, sinuses, individual morphological conditions, wear, and changes resulting from accidents and dental treatments on five crown surfaces of 16 teeth in the lower jaw and 16 teeth in the upper jaw. The permutations and combinations of these variables render duplication improbable. On the other hand, several persons have questioned the uniqueness of the human dentition for six upper and six lower anterior teeth that would normally be found in

Research, Emerging Technologies, and Recent Developments

325

Figure 21.9â•‡ Tom’s Toolbox measÂ�urÂ�ing software. (Photo courtesy of Dr. L. T. Johnson.)

a bitemark. Variations in the crowns of teeth only, which include dental alignment, rotation, wear, size, anomalies, diastemas, fillings, chipping, fractures, notching, spatial orientation (namely, the position), angulation, and horizontal relationship of six teeth within each dental arch, is quite another story. The permutations and combinations of these variables are not anywhere close to the variables associated to the full complement of teeth. The final report, “The Quantification of the Individual Characteristics of the Human Dentition,” claims to have established statistical evidence that quantification of the dental characteristics can be accomplished and that it is feasible to expand the study to begin a database. The development of this data set indicates that it is possible to support opinion testimony with statistical evidence and that an indirect benefit of the study was the development of an automated software program to measÂ�ure the characteristics effectively, rapidly, and even more accurately than the tools available in Adobe Photoshop do [9] . As a result of the study, an application, Tom’s Toolbox, was developed by Marquette University and collaborators. The application utilizes a palette of 10 markers, one pixel in size, each having a different green color value from 1 to 250. The markers are inserted at the starting and ending points of the areas to be measÂ�ured

(FigureÂ€ 21.9). Each image file is read by the program’s ability to recognize the difference in green color value of the markers and location of the marker (column and row); it mathematically calculates both distance and angles of rotation. The calculations are saved by the application and added to a developing data set. A highly favorable comparison of the automated measÂ�ureÂ�ments of Tom’s Toolbox with manual measÂ�ureÂ� ments of the same scaled images was undertaken with the measÂ�ure tool in Adobe Photoshop CS 2. According to Johnson, this validated the accuracy and reliability of the automated program [10]. Subsequent to the methodology paper, the completed study, quantifying six upper and six lower dental measÂ�ureÂ�ments in a sample of 400 males, aged 18–44, was published. FigureÂ€ 21.10 represents the mesiodistal widths of centrals and laterals and the arch widths of the adult male dentitions in Wisconsin (reproduced with kind permission from the Journal of Forensic Identification) [11]. The volunteer samples were derived from male Marquette University dental school clinic patients and volunteers from two Wisconsin Air National Guard wings in Milwaukee and Madison. They represented a population composed of white, black, Asian, and Hispanic individuals. Percentages of each group were not provided in the publication.

326

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

N

Very Uncommon Lower Width Values

Uncommon Lower Width Values

Common Width Values

Uncommon Upper Width Values

Very Uncommon Upper Width Values

Mandibular Arch Arch width (cm)

415

≤2.26

>2.26 to ≤2.37

>2.37 to ≤2.96

>2.96 to ≤3.11

>3.11

Right lateral incisor no. 26 (mm)

416

≤4.66

>4.66 to ≤5.02

>5.02 to ≤6.75

>6.75 to ≤7.00

>7.00

Right central incisor no. 25 (mm)

419

≤4.33

>4.33 to ≤4.58

>4.58 to ≤6.20

>6.20 to ≤6.63

>6.63

Left central incisor no. 24 (mm)

419

≤4.24

>4.24 to ≤4.63

>4.63 to ≤6.12

>6.12 to ≤6.52

>6.52

Left lateral incisor no. 23 (mm)

416

≤4.40

>4.40 to ≤5.09

>5.09 to ≤6.82

>6.82 to ≤7.14

>7.14

Maxillary Arch Arch width (cm)

412

≤2.86

>2.86 to ≤3.00

>3.00 to ≤3.66

>3.66 to ≤3.77

>3.77

Right lateral incisor no. 7 (mm)

416

≤3.46

>3.46 to ≤4.59

>4.59 to ≤7.44

>7.44 to ≤7.73

>7.73

Right central incisor no. 8 (mm)

419

≤6.95

>6.95 to ≤7.41

>7.41 to ≤9.57

>9.57 to ≤10.06

>10.06

Left central incisor no. 9 (mm)

418

≤6.66

>6.66 to ≤7.38

>7.38 to ≤9.49

>9.49 to ≤9.91

>9.91

Left lateral incisor no. 10 (mm)

419

≤3.92

>3.92 to ≤4.61

>4.61 to ≤7.24

>7.24 to ≤7.78

>7.78

Figure 21.10 Widths of teeth and dental arches. (Johnson, L. T. et al. 2009. Journal of Forensic Identification 59 (6): 609–625. Reproduced with permission.)

When it is fully developed, the pattern analysis technology will record an analyst’s examination of patterns for reproducibility by another analyst and enable a statistical comparison of the analysis measurements with the developing internal data set to quantify the occurrence and continue to add those measurements of the patterns to the size of the data set (L. T. Johnson, personal communication, 2010). The distribution and licensing of the software application can only be made with a governmental agency or academic institution. This author has not evaluated the application.

21.7 Avon, 2007 This 301-page thesis provided information on the clinical observations and histopathological aspects of bitemark injuries in an in vivo pig model [105]. It demonstrated that training and certification of professionals who are to give opinion evidence in cases of bitemark patterned injuries is important to the successful outcome of the analysis. Nevertheless, even members of the expert diplomate group can make mistakes in their conclusions. The results from this study could lead to the argument that bitemark analysis is subjective and does not belong in a court of law. This is not a valid conclusion, according to that author. As long as bitemark evidence recovered from the victim is of significant forensic quality and the examiner is a well-trained professional, thorough in

the analysis and conservative in conclusions, such analysis is a valuable tool to assist the trier of fact. Other conclusions included: • The use of a bitemark device to produce a bitemark on the skin of a pig in vivo results in wounds that are consistent with those of dermal bitemarks in humans. • Clinical observations of bitemarks on the skin and the analysis of the histopathological sections demonstrate a difference between bitemarks produced during life and those produced after death. • Transmission of light passing through the excised bitemark is not different prior to and following formalin fixation. • Transillumination of a bitemark provides additional information in the interpretation of bitemarks. • There are differences in the ability of ABFO diplomates, persons trained, and those untrained with respect to the ability to identify bitemark suspects correctly. • Training and the number of previous bitemark cases were significantly associated with an increased ability to identify the correct suspect. • Computer program analysis was significantly associated with an increased ability to identify the correct suspect.

Research, Emerging Technologies, and Recent Developments

21.8 The NAS Report, 2009 The National Academy of Sciences released its report, entitled “Strengthening Forensic Science in the United States: A Path Forward,” in February 2009. It was a virtual awakening—particularly for the fields of impression evidence in the forensic sciences (fingerprinting, shoe print, tire print, tool marks, firearms, bitemark, etc.). The questions the report raised can be summarized as follows: • Is there research to examine observer performance and cognitive psychology on the potential for bias and error in observers? • Is the forensic discipline founded on a reliable scientific methodology that gives it the capacity to analyze evidence and report findings accurately? • Are practitioners in a particular forensic discipline reliant upon interpretation that could be tainted by error, the threat of bias, or the absence of sound operational procedures and robust performance standards? • Are there established protocols for the forensic examinations, methods, practices, and standardized terminology and reporting methods? • Is there research that addresses issues of accuracy, reliability, validity, information sharing, and proficiency testing in the forensic science discipline? If not, the National Institute of Forensic Science (NIFS) should competitively fund peer-reviewed research in the following areas: (a) studies establishing the scientific bases demonstrating the validity of forensic methods, and (b) the development and establishment of quantifiable measures of the reliability and accuracy of forensic analyses. • Is there a code of ethics for the forensic science discipline and a certification process? • Is there training and education, beyond apprentice-type training, based on scientifically valid principles and practice with rigorous interdisciplinary education? The report was particularly critical of bitemark evidence: • On operator error and bitemarks, it claimed that there is no science on the reproducibility of the different methods of analysis that lead to conclusions about the probability of a match. This includes reproducibility between experts and with the same expert over time.

327

• There are no studies of large populations to establish the uniqueness of bitemarks. • Rarely are comparisons made between a bitemark and dental models from other individuals in addition to the biter. • There is no central repository of bitemarks and patterns. • There is no established science indicating what percentage of the population or subgroup of the population could also have produced the bite. • As with other “experience-based” forensic methods, forensic odontology suffers from the potential for large bias among bitemark experts in evaluating a specific bitemark. • Blind comparisons and second opinions are not widely sought. • Even though forensic odontologists understand the anatomy of teeth and the mechanics of biting, the scientific basis is insufficient to conclude that bitemark comparisons can result in a conclusive match. Some of the basic problems inherent in bitemark analysis and interpretation include: • The uniqueness of the human dentition has not been scientifically established. • The ability of the dentition, if unique, to transfer a unique pattern to human skin and the ability of the skin to maintain that uniqueness have not been scientifically established. With regard to the question of proficiency testing, the report stated that, although many forensic science disciplines have engaged in proficiency testing for the last several decades, several courts have noted that proficiency testing in some disciplines is not sufficiently rigorous. Regarding certification, it stated that individual certification of a forensic science professional should be mandatory and that all forensic science professionals should have access to a certification process. 21.8.1 AAFS Position Statement, 2009 The American Academy of Forensic Sciences (AAFS) is a multidisciplinary organization whose objectives are to promote education, foster research, improve practice, and encourage collaboration in the forensic sciences. Following the NAS report, it unanimously voted to support the recommendations of the report, while adopt-

328

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

ing seven principles and three specific actions. It noted that attorneys and judges who work with forensic scientists and forensic science evidence should have a strong awareness and knowledge of the scientific method and forensic science disciplines. 21.8.2â•…A BFO Response and Guidelines, 2010 The ABFO, in turn, implemented the recommendations of the NAS report for items under its mandate and created a formal Training/Education Committee and a Continuing Education Committee. Their goals are to design quality-control procedures that identify mistakes, fraud, and bias; confirm the continued validity and reliability of standard operating procedures and protocols; ensure that best practices are being followed; and correct procedures and protocols that are found to need improvement. The Certification and Examination Committee is to provide sample examination questions for and mentorship programs with trainees receiving a working knowledge of basic quantitative calculations, including statistics and probability. The Continuing Education Committee is to develop voluntary proficiency testing for diplomates accessible on the Web. Develop and implement feedback loops that allow the diplomate and the committee to develop corrective measÂ�ures and additional proactive programs. The use of the ABFO bitemark terminology guidelines and standards should be followed in all written communications regarding evidence, analysis, and opinions. This will eliminate a lot of confusion and misunderstanding concerning the expert’s opinions.

21.9â•…SUNY, 2006– In 2006, prior to the publication of the NAS report, a collaborative effort and information sharing to study bitemarks was under way between the faculties of dentistry at the State University of New York at Buffalo and McGill University in Montreal. The approaches between projects differed from human cadaver models in the former and to live porcine subjects in the latter. From 2008 to 2010, many papers on these studies were presented at the annual meeting of the American Academy of Forensic Sciences that mainly focused on the properties of skin, with subsequent publication in the Journal of Forensic Sciences [12–14].

21.10â•…McGill University, 2004– McGill University’s faculty of dentistry inaugurated the first continuing education forensic dentistry course online in 2004 [15]. It provides theoretic and practical training in forensic dentistry that runs from September to August of the following year. The 24 weeks are dedicated to theory, readings, assignments, and weekly live chats between participants and the course director. Two additional full weeks (10 days) are spent at the Laboratoire de Sciences Judiciaires et de Médecine Légale (forensic lab) for practical hands-on training—in May on identification and in August on bitemarks. The latter module provides not only practical material for participants but also significant amounts of material on bitemarks with a known biter (gold standard) for research purposes. The results have been reported in presentations at the American Academy of Forensic Sciences [16–19] in recent years and are presented here in written and photographic form for the first time. 21.10.1â•…Extracellular Fluid Expulsion Unreported phenomena until now have been the expulsion of extracellular fluid from the dermis when sufficient force is applied during bitemark infliction (FiguresÂ€ 21.11–21.13) and superimposed bitemarks (FigureÂ€ 21.14). FigureÂ€ 21.11 shows extracellular fluid expulsion resulting from squeezing of the tissue between the upper and lower teeth. FigureÂ€ 21.12 is a bitemark photographed from a variety of angles immediately after infliction. Note the extracellular fluid within the tooth indentations as well as between the dental arches. There was no fluid on the skin prior to infliction. FigureÂ€21.13 is a close-up photograph of the previous figure, and FigureÂ€21.14 shows superimposed bites with fluid expulsion. Readers should be aware that the perpetrator’s salivary DNA might be diluted as a consequence of commingling with the recipient’s extracellular fluid, in addition to the blood, if the bite or other object perforates the skin. 21.10.2â•…Clothing DNA collection from clothing is indicated if a pattern injury resembling a bitemark is found on the skin. If a bitemark has been inflicted through clothing with sufficient force, it might also cause extracellular fluid expulsion.

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Figure 21.11â•‡ Close-up views of bitemark infliction and cellular fluid expulsion.

This fluid expulsion may be visible on the clothing or might have evaporated. FiguresÂ€ 21.15–21.18 highlight bitemarks through a 50% cotton/50% polyester T-shirt. FigureÂ€ 21.15 illustrates absorption of extracellular fluid by a cotton shirt, an artifact indentation from the autopsy table in the alternate light imaging (ALI) photograph, and an “invisible” laceration between the dental arches viewed in ultraviolet and black and white photographs. FigureÂ€ 21.18 appears to have an intra-arch contusion, but it is a blood vessel engorgement that diminished with time. There are several photographs throughout this chapter where blood vessel engorgement may be misinterpreted as contusion, particularly in immediate postinfliction photographs. The gross appearance cannot be differentiated one from the other. A second phenomenon shows a widening/increase in the arch dimension since it is perpendicular to the tension lines (Langer’s). FigureÂ€ 21.19 depicts a bitemark through a 45% cotton/55% polyester shirt and an intra-arch blood vessel engorgement associated with the lower arch. FigureÂ€ 21.20 is a bitemark inflicted through a 100% cotton shirt. This bitemark, inflicted 29 minutes antemortem, shows blood vessel engorgement immediately after bitemark infliction. The postmortem photographs,

taken 5 days later, show no macroscopic signs of this engorgement (FigureÂ€21.21). FigureÂ€21.22 identifies a bitemark inflicted 50 minutes antemortem on the chest cavity through black pantyhose made of 97% nylon and 3% spandex. What is clearly identified as the lingual and incisal edges of the anterior teeth has clearly disappeared in the postmortem photograph taken 5 days later (FigureÂ€21.23). FiguresÂ€ 21.24–21.26 represent bitemarks through 100% nylon pantyhose. Usually, clothing interference will affect the clarity of the bitemark. Depending on the type and thickness of clothing and under certain circumstances, there may be very little transference of dental characteristics to skin. In the cited examples, the clearest of the bitemarks, inflicted 66 minutes antemortem in the middle of the back, was photographed in ALI 3 days postmortem (FigureÂ€21.25). FigureÂ€21.26 is a bitemark inflicted 35 minutes antemortem through ultrasheer pantyhose. Note the lateral hemorrhages resulting from the pinching of tissue between upper and lower dental arches. Fiber pattern transference may occasionally be seen within bitemark indentations (FigureÂ€21.27). These generally disappear shortly after bitemark infliction as a result of skin resiliency and elasticity.

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Figure 21.12â•‡ Bitemark immediately after infliction from several angles.

Another research project [20] studied various fabrics, including polyester (100%), nylon (90%)/Â�spandex (10%) blend, nylon (80%)/spandex (20%) blend, and polyester (64%)/nylon (36%) blend. All of the fabrics exhibited different weave patterns with varying primary fiber diameters. Bites were inflicted through each fabric on human cadavers and photographed at 1 hour, 24 hours, and 96 hours after bitemark infliction. Unlike the irregular detail seen on tooth surfaces, fabric possesses two recognizable geometric properties. One is the primary fiber diameter, and the second is the geometric nature of the weave. It is these features that transfer to and are recognizable on skin. One or the other of these properties may dominate in the bitemark imprint, depending on the relative sizes of these features. In this case, the fabric pattern dominates over the skin pattern when superimposed. In this study, the fabric weave imprint in cadaver skin persisted long after the bitemark had rebounded and become invisible by conventional photographic means. A correlation was demonstrated between the attributes of the fabric’s material and weave pattern to the time persistence of the bitemark. The SEM proved to be an invaluable tool in visualizing the patterns after

a period of time because they become essentially invisible to the eye. This study demonstrates that additional information may be obtained from microscopic analysis and best-practice exemplar fabrication. It indicates that there may be hidden information present on the skin surface that may persist and be recognizable for some time period after death. 21.10.3â•…Hair Presence and Removal Hair removal should only be considered following DNA collection, particularly if the underlying patterned injury is assumed to be a bitemark. FiguresÂ€21.28–21.33 illustrate the presence of hair camouflaging a patterned injury. Following partial hair removal (FigureÂ€ 21.28), the injury can be positively identified as a human bitemark. FigureÂ€ 21.34 illustrates a bitemark inflicted partially through an area containing hair. Several methods of hair removal have been evaluated [18] to minimize potential modifications to a bitemark. These include the use of electric shavers, disposable razor blades in combination with cleaning agents (ethanol, dishwashing liquid,

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Figure 21.13â•‡ Bitemark close-up immediately after inflic-

tion. Note the initial contact of the maxillary dentition and the cellular fluid expulsion.

and shaving cream) or depilatory substitution (Veet®). Clearly, the most effective means of hair removal without potential damage to the bitemark remains the cautious use of a depilatory applied to the bitemark indentations. Care should be employed to minimize dispersion of the depilatory beyond the bitemark outline. Failure to heed this warning may cause potential loss of adhesion of the impending excision ring to skin. FigureÂ€ 11.1 depicts depilatory application and FigureÂ€11.2 shows the area following hair removal from a bitemark. Following its application, FiguresÂ€11.3 and 11.4 highlight the clarity of the individual bitemarks, and the ALI photographs accentuate dental outline in particular (FigureÂ€21.35). 21.10.4â•…Bite Slippage FiguresÂ€21.12 and 21.13 show an initial contact of maxillary teeth with skin and a slippage to lessen interarch opening diameter. This is unusual since the lower arch typically produces drag marks. Note the extracellular fluid resulting from the bitemark. 21.10.5â•…Overlapping/Superimposed Bites FigureÂ€21.36 illustrates a vital bitemark on a hip at the time of infliction and a second blanching overlapping bite oriented 180° opposite the first (FigureÂ€ 21.37). FigureÂ€21.38 depicts superimposed bites on the creased

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lividity side 3 days postmortem, followed by the Dorion type V excision technique (FigureÂ€21.39). Note the degree of difficulty in orienting the bitemarks based upon the postmortem (color, ALI, ultraviolet [UV]) and excision photographs alone. The amount of postinfliction tissue rebound is also remarkable. FiguresÂ€21.40 and 21.41 illustrate side-by-side overÂ� lapping vital bitemarks (43 minutes) on a curved surface at the time of infliction and 3 days postmortem. FigureÂ€ 21.42 depicts the excised specimen and Figure 21.43 the transilluminated specimen. Note the amount of bitemark distortion from infliction to rebound. In addition, there is substantial internal tissue damage in the absence of skin perforation. FigureÂ€21.44 portrays side-by-side overlapping bitemarks with the same orientation. Note that the last inflicted bitemark is blanching. FigureÂ€ 21.45 displays bitemark photographs at the time of infliction, 3 days postmortem, and ALI photographs (FigureÂ€21.46). Note the amount of bitemark distortion from the time of infliction to skin rebound. Overlapping side-by-side bitemarks created on a curved surface may give rise to severe distortion of each component (FiguresÂ€21.47 and 21.48). FigureÂ€21.49 shows the creation of a bitemark and extracellular fluid on the skin. At first glance, there appears to be a single bitemark; however, closer observation denotes either slippage or a double bite. The 3-day postmortem photographs clearly indicate bitemarks that have changed in appearance following tissue rebound (FigureÂ€21.50). FiguresÂ€21.14 and 21.51 illustrate the creation of sideby-side overlapping bitemarks with the same maxillary to mandibular orientation and the presence of extracellular fluid. FiguresÂ€21.52 and 21.53 further record tissue rebound to its resting position, excised and transilluminated 5 days postmortem. Note the bitemark color changes in FiguresÂ€ 21.54– 21.62. All three sets of bitemarks are antemortem (20, 15, and 5 minutes, respectively); in the absence of clothing, double bites on the lividity side exhibit marked creasing during infliction and in postinjury tissue rebound (FigureÂ€21.56). Readers should be cautioned at this point that tissue rebound does not always equate to bitemark distortion. FiguresÂ€21.63 and 21.64 illustrate lividity-side bites that have undergone creasing from the body lying on them. 21.10.6â•…Disproportionate Dimensional Distortion Bitemark dimensional changes can result from a number of factors, including the location on the body; see FiguresÂ€ 21.65 (shoulder), 21.66 (chest/rib cage), 21.67

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Figure 21.14 Close-up of side-by-side overlapping bites. Note the presence of extracellular fluid resulting from the bitemarks.

(axillary area), 21.68 (axillary area), 21.69 (hip), and 21.70 (thigh), as well as Figure 21.23 (chest/rib cage). Readers are reminded that the previous site description refers to the piglet anatomy. There are undoubtedly areas of the human anatomy that would lend themselves to a comparable degree of distortion. Figure 21.70 records the amount of distortion from infliction to tissue rebound and a photographic comparison by superimposition. Figure 21.71 is a bitemark parallel to Langer’s lines. Note the elongation and narrowing of the bitemark. Examples of bitemarks oblique to Langer’s lines are seen in Figures 21.21, 21.27, 21.65, and 21.72. Figures 21.73–21.75 depict movement of the biter’s head and/or the recipient’s body. Figures 21.74 and 21.75 record the amount of distortion from infliction to tissue rebound and a photographic comparison by superimposition. The latter bitemarks are on the lividity side. Overlapping bitemarks are shown in Figures 21.44– 21.46, and Figures 21.76–21.81 illustrate creasing during biting. Figures 21.36, 21.67, 21.68, 21.72, 21.77, 21.82, and

21.83 illustrate additional lividity-side bites that have undergone creasing from lying on them. 21.10.7 Bitemark Profiling Figure 21.84 represents three bitemarks inflicted by the same dentition. They are different in size and appearance. One could lead investigators on an erroneous path if a dental profile is created based upon each bitemark: a wide, relatively flat dental arch (left), what appears to be diestemas or interdental spacing or missing teeth with lower misalignment (center), and two relatively elongated narrow arches (right). In recent presentations [14,21] and a soon to be published article, the authors caution against profiling the biter from a bitemark. The study looked at predicting dental characteristics from a bitemark (bitemark profiling) of 66 postmortem bitemarks in human cadaver skin. The results showed that distortional ranges were nonuniform between bites, as well as within each bite, and 38% of the bites created patterns that could be

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Figure 21.15â•‡ Bitemark through shirt (upper left) and with ALI (upper right), UV (lower left), and gray scale (lower right).

misleading if profiled. Features were present or absent that were inconsistent with the biter’s dentition. This author recently reported the results of a study on bitemark profiling based upon color, UV, and ALI photographic interpretation [21]. The bitemarks were created with a known biter (gold standard). Two experienced responders analyzed 25 scaled (ABFO no. 2) antemortem bitemark color photographs. They were asked to evaluate: • The evidentiary value of each bitemark (minimum, poor, excellent) • Whether the bitemarks could be identified as having been produced by the same person without having dental casts for comparison (i.e., how many biters inflicted the bitemarks) • The evidentiary value of the photographic type: color • The degree of certainty that bitemarks were created by the same person (reasonable medical certainty, probable, inconclusive, exclusion) Two weeks following that exercise, the responders were asked to evaluate 17 UV photographs of the same

bitemarks and, later, 23 ALI photographs, without referring to previous sets of photographs. The evidentiary value of the color and UV photographs had the responder with the most experience score higher, and the percentage distribution of correct answers was highest in the “poor” evidentiary value category. For the ALI photos, the responder with the least experience had the higher score, and the percent distribution of correct answers was highest in the “excellent” evidentiary value category. The conclusions were similar to the previous study: Bites created patterns that could be misleading if profiled since only a small percentage of the total number of correct answers can correctly be identified as coming from the same biter for color, UV, and ALI photography. 21.10.8â•…Lingual Markings Certain lingual markings remained 48 hours after infliction (FiguresÂ€ 11.4, 21.85, and 21.86), while others disappeared shortly after infliction (FiguresÂ€21.12, 21.22, 21.54, 21.55, 21.63, 21.66, 21.67, 21.72, 21.87, and 21.88). Why the difference? It might have to do in part with the amount of force applied and type of underlying tissue (mobility, cartilage, fat, muscle, etc.).

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Figure 21.16 Bitemark immediately after infliction (upper left, upper right), through clothing (lower right), and with ALI no. 12 filter 3 days postmortem (lower left).

Figure 21.17 Bitemark through cotton shirt (left) and immediately after infliction (right).

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Figure 21.18â•‡ Bitemark through cotton shirt immediately after infliction (upper left, upper right) and 3 days postmortem (lower left, lower right).

An ALI photograph (FigureÂ€ 21.89) depicts lingual markings that are not observed in the color photograph of the same bitemark (FigureÂ€21.28). This confirms the importance and even the necessity of getting as many types of photographs as one can—color, infrared (IR), UV, and ALI. 21.10.9â•…Disappearing Teeth In FiguresÂ€21.66, 21.90, and 21.91, it appears as though sufficient force was initially applied. However, with tissue rebound, the evidentiary value of the bitemark is poor because dental detail has diminished. 21.10.10â•…Bitemark in the Presence of Other Trauma Bitemarks in the presence of other trauma may render perpetrator identification more difficult. The trauma

may include such things as abrasions (scratch marks), stab wounds, bullet holes, etc. (FiguresÂ€ 21.15, 21.62– 21.65, 21.82, 21.92, and 21.93), or secondary factors, such as scars, tattoos, etc. 21.10.11â•…Autopsy Artifacts Autopsy artifacts are usually accidental. They include such things as scalpel nicks or perforations. At other times, there might be a simple explanation, such as the imprint from the autopsy table (FiguresÂ€21.65, 21.67, and 21.83). 21.10.12â•…Ears and Cartilage FigureÂ€ 21.94 illustrates an antemortem bitemark on a piglet ear immediately after infliction. The highly vascularized area did not demonstrate marked postinfliction hemorrhaging. In fact, the bitemark was barely visible postmortem.

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Figure 21.19â•‡ Bitemark through clothing immediately after infliction (upper left, upper right), 5 days postmortem (lower left), and initial use of depilatory in indentations (lower right).

21.10.13â•…Nipples FiguresÂ€21.21, 21.91, and 21.95–21.97 depict a complicating factor of bitemark assessment since it is adjacent to or through a piglet nipple. 21.10.14â•…Complementary Information FiguresÂ€21.28–21.30, 21.79, 21.88, 21.89, and 21.98–21.106 are photographs providing complementary information on the bitemark. The importance of having different types of photographs (color, IR, UV, ALI) or other forms of visual record such as transillumination to maximize information cannot be overstated. Readers should have observed the different appearance of ALI photographs in this atlas. In the 2005 bitemark project, the ALI photographs were taken with a no. 15 yellow filter at f/16 aperture, tripod stabilized. The Poly Light 500X at wavelength 450 nm and a Dell® computer acted as shutter with the Nikon capture card

4.0. In 2006, a Nikon D2X, CMOS, 12 megapixel with no. 12 yellow filter had replaced the Canon. By 2007, the color, UV, and IR photographs were achieved with the Fuji Fine Pix S3 Pro Ver. 2.72 camera. 21.10.15â•…Bitemarks Containing Fewer Than 12 Teeth Bitemarks containing fewer than 12 teeth may or may not pose a problem for perpetrator identification (Figures 11.2, 21.62–21.65, and 21.107–21.112). Figure 21.113 illustrates a dentition with 11 anterior teeth; however, the alignment and the horizontal relationship of these teeth would give rise to a very particular bitemark. 21.10.16â•…Bitemark Orientation It is not always an easy task to orient bitemarks, even with a complement of different types of photographs

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Figure 21.20â•‡ Bitemark through clothing immediately after infliction.

(FiguresÂ€ 21.12, 21.25, 21.37, 21.38, 21.73, 21.87, 21.104, and 21.114–21.116). 21.10.17â•…One-Sided Bite Following bitemark infliction, the cotton shirt was removed to expose the bitten tissue (FigureÂ€ 21.117). There appears to be more teeth registering on the right than the left side of the bitemark (also see FigureÂ€18.74). 21.10.18â•…Muscle Perforation: Three Dimensional In FiguresÂ€21.118 and 21.119, the skin damage appears to be minimal with no perforation. The connective tissue and muscle damage is extensive and three dimensional. In the first edition, this phenomenon was reported in a homicide case (FigureÂ€18.61 in this edition). It was possible to reproduce this experimentally on two separate occasions. It is still a mystery why and when this occurs, particularly in the absence of skin perforations.

Additional examples of skin perforations by teeth (FigureÂ€21.120) and in the deeper layers without skin perforation are seen in FiguresÂ€21.121–21.123. FigureÂ€21.124 is an example of a bitemark muscle injury and inadvertent scalpel perforation. 21.10.19â•…Contusion within a Bitemark Note the different hemorrhagic patterns in each of the previous examples. Some cover the entire surface between the upper and lower dental arch imprints, some outline the dentition, and others are a combination of the two. FigureÂ€21.29 depicts what appears to be a central contusion within a bitemark, and FigureÂ€21.125 shows a small intra-arch and a peripheral contusion to the right. Note that most of the extracellular fluid has been absorbed by the shirt and that the peripheral contusion seems to have disappeared with time. A partial explanation of the “disappearance” is due to freezing (Section 21.10.22). Compare FiguresÂ€ 21.92–21.125. The specimen in FigureÂ€ 21.92 was not frozen, however. A possible

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Figure 21.21 Bitemark immediately after infliction (upper left), 5 days postmortem (upper right), and with ALI (lower left, lower right). Note distortional changes with tissue rebound.

Figure 21.22 Bitemark at time of infliction through pantyhose (left) and 5 days postmortem (right).

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Figure 21.23â•‡ Bitemark through clothing immediately after infliction (upper left, lower left) and 5 days postmortem

(right).

explanation is that it is due to blood vessel engorgement that dissipates over time, rather than a contusion. Compare FiguresÂ€21.22, 21.26, 21.72, 21.112, 21.124, and 21.126–21.129. Cutaneous blood vessel engorgement and/or contusions can occur at the moment of infliction. Blood vessel engorgement can dissipate over time. Contusions, on the other hand, must heal. FigureÂ€21.130 is a postmortem bite running through a zone of lividity. The central portion of the bitemark could be misinterpreted as a contusion macroscopically. 21.10.20â•…A ntemortem versus Postmortem Bitemarks Postmortem bitemarks can be differentiated macroscopically from their antemortem counterparts by their lack of color. There is no hemorrhaging associated with these bitemarks. Bitemarks that were produced within 1 minute of death have the same result as those produced after longer periods of time. FiguresÂ€ 21.131–21.133

exemplify postmortem bitemarks inflicted at different time intervals (FigureÂ€ 21.131 at 2 hours, 21 minutes; FigureÂ€21.132 at 2 hours, 13 minutes; and FigureÂ€21.133 at 53 minutes). 21.10.21â•…Lividity Lividity, also known as livor mortis, is the settling of blood by gravitational forces within dilated capillaries. The lividity side is the side of the body facing the ground. There are two areas of interest on this side of the body: (1) the part in contact with the ground, and (2) the part not in contact with the ground, which is usually blue/ purple in color. FiguresÂ€21.134 (2 minutes), 21.136 (9 minutes), and 21.137 (10 minutes) represent antemortem bitemarks on the lividity side in contact with the ground. FiguresÂ€21.75 (19 minutes), 21.83 (52 minutes), 21.64 (4 minutes), 21.110 (41 minutes), 21.135 (9 minutes), and

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Figure 21.24â•‡ Bitemark immediately after infliction (upper left, upper right) and 3 days postmortem (lower right) in ALI (lower left).

21.138 (7 minutes) represent antemortem bitemarks with the lividity side in partial contact with the ground. FigureÂ€ 21.139 embodies a postmortem bitemark (2 hours, 20 minutes) with the lividity side in contact with the ground. FiguresÂ€21.107 (7 minutes) and 21.108 (13 minutes) represent postmortem bitemarks with the lividity side not in contact with the ground. FiguresÂ€ 21.104 (2 hours, 20 minutes) and 21.130 (3 hours, 40 minutes) represent postmortem bitemarks with the lividity side in partial contact with the ground. 21.10.22â•…Freezing Bodies can be found in freezers, after being frozen and then dumped, or after a cold winter. Bitemarks are affected by many factors and conditions. What happens to bitten mammalian skin that has been frozen and thawed? What are the variables that affect the speed of freezing and thawing of a body? Can freezing results be differentiated between a live versus a deceased person freezing? What are the effects of skin exposure, temperature, wind chill, humidity, clothing, and animal activity? Freezing may temporarily prevent decay, but skin may discolor slightly to an orange and go all the way to black for extremities. What are the macroscopic and

microscopic changes in bitemarks after freezing has taken place? Do these impact the evidentiary value of a bitemark and its analysis? Many of these questions were answered in a recent research project [22]. Freezer burn of a bitemark (FiguresÂ€ 21.110 and 21.142) occurs as a result of the cold air around the body being less humid than the body itself. The water molecules in tissue burst to equilibrate the vapor pressure. The part of the tissue that is deprived of moisture becomes dry and shrinks and can affect the appearance and the detail of a patterned injury. The result is a darkening of the skin color (FiguresÂ€ 21.102, 21.110, 21.111, and 21.140–21.142). The volume of a live human body results in a special freezing behavior, but dead bodies follow only physical laws. Laws are ruled by factors like heat transfer coefficient, the body’s surface, differences between surface and environmental temperatures, thermal conductivity, and the distance over which heat is transported. Because of its volume and the surface exposed, the human body is prone to freezing slowly. The process causes extracellular crystallization of the water that leads to an increased salt concentration in the remaining noncrystallized extraÂ�cellular fluid. This increased osmolarity creates a vacuum and the intracellular fluids are attracted out of the cell, causing dehydration of the cell, breakage

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Figure 21.25â•‡ Bitemark immediately after infliction (upper left), 3 days postmortem (upper right), with ALI no. 12 filter (lower left), and UV (lower right).

and deformation of the cell membrane, and deformation of the cell nuclei. The cell shrinkage created by this slow freezing process leads to cell-to-cell cohesion loss and/or vacuole formation in tissue (FigureÂ€21.143). See Chapter 22, Section 22.4, for additional examples. The freezing and thawing processes break cell organelles, thereby releasing enzymes. This causes diffusion of soluble contents of the body like blood. Also, fragile pulmonary capillaries are affected and a considerable amount of blood can be lost during the thawing process, further contributing to dehydration. All of these impact the bitemark. When skin is bitten, fluid displacement occurs. During biting, some fluids are pushed toward the exterior of the bite and will disperse in the surrounding tissue. The fluids that are pushed toward the center of the bite will not disperse as easily, and more freezing artifacts in the form of crystallization are prone to occur. At the level of tooth contact with skin, as with blunt trauma injury, fluids are pushed away from the site and freez-

ing does not cause much crystallization at the site of tooth impact. Lividity blood pooling and central contusions are generally present but at a lesser degree than at the stage prior to freezing. This is possibly caused by the dissolution of soluble constituents by release of enzymes during the thawing process and also the loss of blood caused by fragile capillaries affected during the freezing process.

21.11â•…Bitemark Comparison Methods used in bitemark comparison have changed over the years. There is no question that the methods currently employed are more accurate and less subjective than they were in the 1970s. At that time, handdrawn overlays were made of the suspect dentition and compared directly to a 1:1 life-size photograph of the bitemark. FigureÂ€21.144 demonstrates the “scraping” of the incisal edges dragging over the back. The alignment of the individual teeth is demonstrated.

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Figure 21.26â•‡ Bitemark made through pantyhose.

Dorion [23] discussed the method of using a photocopy machine to produce dental cast overlays. Alternatively, a scanner was used for the same purpose. The software programs used in 1997 were Photoshop 3.0, ImagePals 2.0, and SigmaScan/Image 1.2. In the 1980s video comparison techniques became popular. In FigureÂ€ 21.145, a suspect’s dental casts are compared to the excised fixed and transilluminated bitemark on a breast. Three-dimensional vinyl templates and Styrofoam were introduced as bite registration medium in bitemark analysis in 1990. Clear vinyl hygroscopic templates 0.02 mm in thickness—commonly known in dentistry as temporary splint material—are heated and molded to a dental cast under vacuum (FigureÂ€21.146). In the intervening years, computer-generated overlays have been favored over the hand-drawn variety. In FigureÂ€ 21.147, computer overlays are used to demonstrate the differences between two suspect dentitions in an infanticide case. This is by no means an ideal bitemark since it is dated, healing, and lacks individual

dental characteristics. On the other hand, the bruise has certain parameters that, when taken as a whole, can be analyzed in relationship to suspect dentitions. This example is a case of exclusive opportunity limiting the suspect population to two adults. In FigureÂ€ 21.148, the number and the quality of individual dental characteristics are somewhat limited. However, this is a case of exclusive opportunity with a limiting population of one adult. Authorities wanted to know whether the suspect’s dentition was consistent with the bitemark. Bitemarks on the living have certain limitations since they cannot be excised, transilluminated, and examined histologically. In addition, the healing process limits the time for analysis. FigureÂ€ 21.149 illustrates a healing bitemark on an adult’s arm. Observe the relationship between the abrasions and the suspect dentition. Clearly, the quality of photography must be exceptional to pick up minute details.

Research, Emerging Technologies, and Recent Developments

Figure 21.27 Fiber pattern transference within bitemark indentations.

Figure 21.28 Unshaved (left) and partially shaved (right) skin with bitemark.

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Figure 21.29 Unshaved and shaved skin with bitemark.

Figure 21.30 Color (upper left) and ALI no. 15 filter (upper right), unshaved (lower left) and partially shaved transilluminated (lower right) bitemark.

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Figure 21.31 ALI no. 12 filter bitemark photographs before (left) and after (right) depilatory in bitemark indentations.

Figure 21.32 Antemortem bitemark photographed 5 days postmortem and ALI.

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Figure 21.33â•‡ Bitemark immediately after infliction (upper left, lower left, lower right) and 5 days postmortem.

Retrospective studies and comparisons are interesting in light of the new technologies. New technologies were applied to a bitemark case of a female homicide victim from the mid-1980s. The effects of the new technologies are not only more visually appealing but are also more intelligible for the layman. FiguresÂ€21.150–21.154 represent a bitemark on an arm, the excised and transilluminated specimen, and the respective points of reference. The fixed bitemark demonstrates dental characteristics of tooth alignment, size, and detail not apparent on the arm itself (FigureÂ€21.150, upper left, upper right; FigureÂ€21.154, upper). Why certain details become more apparent following fixation is unclear. The buccal cusp of the perpetrator’s upper left first bicuspid (dental cast flipped to match the corresponding contusion on the bitemark photograph) is fractured and missing. The interrelationship between the underlying subcutaneous hemorrhage and the surface representing class and individual dental characteristics is decidedly more visual and intelligible.

Having the occlusal as well as the frontal view of the dentition makes it more three dimensional. I have chosen the maxim “pictures are worth a thousand words” for good reason.

21.12â•…Summary Human bitemark analysis is by far the most challenging and difficult aspect of forensic dentistry. Oral presentations devoted to bitemarks—and, in particular, bitemark research at the American Academy of Forensic Sciences’ annual meeting—have steadily increased from 1999 to 2010 [24–35], as have articles in the Journal of Forensic Sciences [36–103] and other journals [104–111]. What does the future hold? Continued research and educational programs are the key. Why are certain bitemark cases controversial? Such cases are usually associated with one or more of the following issues:

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Figure 21.34 Bitemark immediately after infliction (upper left, upper right) and 5 days postmortem (lower left,

lower right).

• The examiner’s lack of knowledge, training, and/or experience • Failure to follow established protocol or to limit methods • Examination of substandard material (quantity and/or quality) • Failure to obtain all of the available information before examination and conclusions • Using untested, unproven, or unpublished methods or procedures, or those that cannot be demonstrated or duplicated

In many controversial bitemark cases, the expert was asked to rely on limited information either about the case itself or the material provided. The expert may only have had access to limited and poorly defined photographs on which to base conclusions. As a result, the expertise has been brought into question. Even the most accomplished forensic dental expert should be in the position to qualify the conclusions based on the material received. Poor-quality photographs cannot be compared to the wealth of information available when standard protocol and methods have been employed.

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Figure 21.35 ALI bitemark photographs before (upper left, upper right) and following (lower left, lower right) depilatory use.

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Figure 21.36 Initial bite (upper left, upper right, lower right) and overlapping bite with 180° rotational change (lower

left).

Figure 21.37 Opposing (180° rotational change) overlapping bites immediately after infliction (left) and several minutes later (right).

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Figure 21.38 Opposing (180° rotational change) overlapping bites (upper right) and 3 days postmortem (upper left) with

UV (lower left) and ALI (lower right). The skin creasing is due to the body lying on the bitemarks. Note the absence of lividity in this case.

Figure 21.39 Excised Dorion type V bitemark.

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Figure 21.40 Overlapping side-by-side bites on a curved surface immediately after infliction (upper left) and 3 days later (upper right, lower left, lower right).

Figure 21.41 Overlapping side-by-side bites (left) with ALI no. 12 filter (right).

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Figure 21.42 Bitemark at infliction (upper left), 3 days postmortem (lower left), and Dorion type V excision (right).

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Figure 21.43 Four photographs of transilluminated excised bitemark.

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Figure 21.44 Initial bite after infliction (upper left) and overlapping bite on the left of the original bite (upper right, lower left, lower right)

Figure 21.45 Side-by-side overlapping bitemarks at the time of infliction (left) and 3 days later (right).

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Figure 21.46 Side-by-side overlapping antemortem bitemarks photographed 3 days postmortem (upper left, upper right) and with ALI no. 12 filter (lower left, lower right).

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Figure 21.47 Side-by-side overlapping bitemarks immediately after infliction.

Figure 21.48 Antemortem bitemark photographed 5 days postmortem (left) and with ALI (right).

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Figure 21.49 Bitemark immediately after infliction (upper left, upper right), 1.5 minutes later (center left, center right), with lateral (lower left) and frontal (lower right) views.

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Figure 21.50 Antemortem bitemark photographed 5 days postmortem (upper right, lower right) and with ALI before (upper left) and after (lower left) depilatory.

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Figure 21.51 Bitemark immediately after infliction (upper left, upper right) superimposed by an overlapping bite (lower left, lower right). Note the presence of extracellular fluid resulting from the bitemarks.

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Figure 21.52 Side-by-side overlapping bites immediately after infliction (upper left), 5 days postmortem (upper right, lower right), and with ALI (lower left). Note distortional changes with tissue rebound.

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Figure 21.53 Side-by-side overlapping bitemarks in color (upper left), with ALI no. 12 filter (upper right), with Photoshop “black and white” transilluminated (lower left), and with Photoshop “filtered” (lower right).

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Figure 21.54 Bitemark immediately after infliction. Note the presence of extracellular fluid resulting from the

bitemark.

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Figure 21.55 Side-by-side overlapping bitemarks immediately after infliction.

Figure 21.56 Bitemark photographed 5 days postmortem.

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Figure 21.57 Bitemark immediately after infliction (upper left, upper right) and second bite overlapping first bitemark (lower left, lower right).

Figure 21.58 Bitemark immediately after infliction.

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Figure 21.59 Overlapping side-by-side bitemarks immediately after infliction.

Figure 21.60 Color overlapping side-by-side bitemarks 5 days postmortem (left) and with ALI (right).

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Figure 21.61 Bitemark immediately after infliction (upper left, upper right) and second bite to the right overlapping first bitemark (lower left, lower right).

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Figure 21.62 Side-by-side overlapping bites (upper left, upper right) and several minutes later (lower left, lower right).

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Figure 21.63 Bitemark immediately after infliction (upper left, upper right) and 3 days postmortem lividity side (lower left, lower right).

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Figure 21.64 Bitemark immediately after infliction (upper left), 5 days postmortem (upper right, lower right), and with ALI (lower left).

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Figure 21.65 Three days postmortem color (upper left), at the time of infliction (upper right), with ALI no. 12 filter (lower left), and with UV (lower right) photographs of the same bitemark.

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Figure 21.66 Bitemark at infliction (upper left, lower left), 3 days postmortem (upper right), and with ALI no. 12 filter (lower right).

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Figure 21.67 Cast inflicting bitemark (upper left). Note the major bitemark distortion corresponding to the lower dental arch (upper right) and 3 days later (lower right) and with ALI (lower left).

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Figure 21.68 Bitemark immediately after infliction (upper left) and several minutes later (upper right) with close-up (bottom).

Figure 21.69 Color (left) and ALI (right) photographs of the same bitemark.

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Figure 21.70 Bitemark comparison from infliction (left) to rest position (center) and superimposition (right).

Figure 21.71 Three days postmortem color (upper left), UV (upper right), ALI no. 12 filter (lower left), and at the time of infliction (lower right) bitemark photographs.

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Figure 21.72 Bitemark immediately after infliction (upper left, upper right) and 3 days later (lower left) with ALI (lower right). Note the distortional changes and that the lividity runs through half of the bitemark (lower left) in this case.

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Figure 21.73 Distortional changes with tissue crimping (upper left, upper right), ALI (lower left), and UV (lower right).

Figure 21.74 Bitemark comparison from infliction (left) to rest position (center) and superimposition (right).

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Figure 21.75 Bitemark comparison from infliction (left) to rest position (center) and superimposition (right).

Figure 21.76 Close-up of bitemark immediately after infliction (upper left, upper right) and 3 days postmortem (refrigerated) with ALI no. 12 filter.

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Figure 21.77 Bitemark at the time of infliction on posterior piglet thigh. Note the major distortion of tissue.

Figure 21.78 Different views of a bitemark immediately after infliction of a small limb (piglet). Notice the major skin

distortion.

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Figure 21.79 Antemortem bitemark at infliction (upper left, upper right) and a short time later (lower left), and ALI 3 days postmortem (lower right).

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Figure 21.80 Bitemark immediately postinfliction (upper left), 3 days later (upper right), UV (lower left), and ALI (lower right). Note tissue crushing at infliction and distortional changes with tissue rebound.

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Figure 21.81 Bitemark immediately after infliction (upper left, lower left), 5 days postmortem (upper right), and transilluminated (lower right).

Figure 21.82 Bite and scratch mark superimposed in color, with ALI no. 12 filter, and with UV.

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Figure 21.83 Bitemark at infliction (upper left), following lividity (upper right), with ALI (lower left), and with UV (lower right). Note that the upper half of the bitemark is affected by the lividity.

Figure 21.84 These three bitemarks were inflicted by the same dental cast.

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Figure 21.85 Bitemark immediately after infliction (upper left, upper right) and 3 days postmortem (lower left, lower right).

Figure 21.86 Bitemark 3 days postmortem (left) and with ALI no. 12 filter (right).

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Figure 21.87 Color and ALI (lower right) bitemark photographs 3 days after infliction.

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Figure 21.88 Bitemark photographs after depilatory use: color (upper left), transilluminated (upper right), ALI (lower left), and UV (lower right) photos.

Figure 21.89 Two ALI bitemark photographs with no. 15 filter.

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Figure 21.90 Bitemark immediately after infliction (upper left, upper right), 3 days postmortem (lower left), and 9 months after freezing (lower right).

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Figure 21.91 Bitemark immediately after infliction adjacent to piglet nipples (upper left, lower left) and 3 days postmortem (upper right, lower right).

Figure 21.92 Bitemark immediately after infliction (left and center) and 3 days postmortem refrigeration (right). Note dimensional changes.

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Figure 21.93 Postmortem bitemark with a vital abrasion running through it (right) and with ALI no. 12 filter (left).

Figure 21.94 Bitemark on piglet ear immediately after infliction.

Figure 21.95 Bitemark through piglet nipples in color (left) and with ALI no. 15 filter (right).

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Figure 21.96 Bitemark adjacent to piglet nipples.

Figure 21.97 Bitemark adjacent to piglet nipples.

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Figure 21.98 ALI with no. 15 filter (left) and transilluminated bitemark (right).

Figure 21.99 Shaved (upper left) and ALI no. 15 filter (upper right) bitemark, with Dorion type V excised (lower left) and transilluminated partially shaved (lower right).

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Figure 21.100 Color (upper left), UV (upper right), and ALI no. 12 filter (lower left, lower right) photographs of the same

bitemark.

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Figure 21.101 Color (upper left, lower right), ALI (upper right), and UV (lower left) bitemark photographs.

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Figure 21.102 Bitemark 3 days postmortem (upper left), 9 months after freezing in color (upper right), ALI (lower right), and transillumination (lower left).

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Figure 21.103 Four photographs of transilluminated excised bitemark. Note the under-light intensity variation.

Figure 21.104 Postmortem bitemark (left) and ALI no. 12 filter (right) photographs. Note that the lividity runs through half of the bitemark in this case and bitemark interpretation is facilitated by the ALI photograph.

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Figure 21.105 Bitemark photographed 5 days postmortem (upper left, upper right), transilluminated (lower right), and with ALI (lower left).

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Figure 21.106 Bitemark photographed 5 days postmortem (upper left, upper right) and with ALI (lower left, lower

right).

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Figure 21.107 Bitemark inflicted 7 minutes postmortem on the lividity side that was not in contact with the ground.

Figure 21.108 UV (left) and ALI (right) bitemark photographs.

Figure 21.109 Bitemark in color and with ALI no. 12 filter (left).

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Figure 21.110 Bitemark immediately after infliction (upper left), 3 days postmortem (upper right), with ALI no. 12 filter (lower left), and 9 months after freezing (lower right). Note that the skin has freezer burn.

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Figure 21.111 ALI and UV photographs 3 days postmortem (upper left, lower left) and 9 months following freezing (upper right, lower right).

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Figure 21.112 Bitemark immediately after infliction (upper left), 5 days postmortem (upper right, lower right), and with ALI (lower left).

Figure 21.113 Suspect’s dentition is highly irregular.

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Figure 21.114 Bitemark immediately after infliction (upper left) and 3 days postmortem (upper right) with ALI no. 12 filter (lower left) and UV (lower right).

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Figure 21.115 Bitemark immediately after infliction (upper left) and 3 days postmortem (upper right) with UV (lower left) and ALI no. 12 filter (lower right).

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Figure 21.116 Bitemark immediately after infliction (upper left), 3 days postmortem (upper right, lower right), and with ALI (lower left).

Figure 21.117 Color (left) and ALI no. 12 filter (right) bitemark photos.

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Figure 21.118 Bitemark and retention of three-dimensional characteristics of the dentition in muscle tissue. Note the absence of skin perforation and dimensional change of bitemark to muscle damage.

Figure 21.119 Retention of three-dimensional characteristics of the dentition in muscle tissue.

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Figure 21.120 Perforation of skin by the teeth in overlapping bitemarks.

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Figure 21.121 Bitemark and Dorion type V excision technique. Note the subcutaneous hemorrhage in tissue.

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Figure 21.122 Dorion type V excision of overlapping bitemarks (upper left, upper right) with three-dimensional imprint of teeth in tissue (lower left, lower right).

Figure 21.123 Tear in epidermal layer resulting from a bitemark without skin perforation.

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Figure 21.124 Antemortem bitemark with Dorion type V ring placement and excision. Note the subcutaneous hemor-

rhage in tissue.

Figure 21.125 Bitemark views at infliction (upper left, upper right) and 3 days after refrigeration (lower left). Note that the bitemark was inflicted through clothing (lower right) with cellular fluid expulsion.

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Figure 21.126 Bitemark immediately after infliction (upper left), 5 days postmortem (upper right, lower right), and trans illuminated (lower left).

Figure 21.127 Bitemark and Dorion type V excision technique. Note the subcutaneous hemorrhage in tissue.

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Figure 21.128 Bitemark immediately after infliction and 5 days postmortem.

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Figure 21.129 Bitemark hemorrhage photographed immediately after infliction (upper left, upper right) and 13 minutes later (lower left, lower right).

Figure 21.130 Bitemark immediately after infliction (upper left, lower left, lower right) and 3 days postmortem (upper right).

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Figure 21.131 Three views of a postmortem piglet neck bitemark. Note the retention of the bitemark indentations.

Figure 21.132 Bitemark at infliction (upper left), 3 days postmortem (upper right), excised (lower left), and transilluminated (lower right).

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Figure 21.133 A bitemark inflicted 59 minutes after death and photographed 48 hours postmortem.

Figure 21.134 Bitemark inflicted 2 minutes antemortem on the lividity side in contact with the ground.

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Figure 21.135 Bitemark inflicted 9 minutes antemortem on the lividity side in contact with the ground.

Figure 21.136 Body lying on bitemark, lividity side.

Figure 21.137 Shaved (left) and ALI no. 15 filter (right) bitemark.

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Figure 21.138 Bitemark partially included in the lividity.

Figure 21.139 Postmortem bitemark on the lividity side in contact with the ground.

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Figure 21.140 Antemortem bitemark photographed 3 days postmortem (upper left, lower left) and 9 months after the specimen was frozen (upper right, lower right). Note the skin and bitemark color change.

Figure 21.141 Bitemark on nonlividity side photographed 3 days postmortem (left), 9 months after freezing (center), and after excision.

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Figure 21.142 Bitemark on lividity side photographed 3 days postmortem (left), 9 months after freezing (center), and after excision (right).

Figure 21.143 The slow freezing process causes vacuole formation in the epidermal tissue (left). Presence of numerous vacuoles in hair follicle (center). Loss of cellular cohesion by cell shrinkage, membrane breakage, and deformation (right).

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Figure 21.144 Hand-drawn overlays of suspect dentition over bitemark photograph.

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Figure 21.145 Bitemarks on breast (upper) and dental comparison/approximation with transilluminated specimen

(lower).

Figure 21.146 Bitemark on right thigh (upper left), excised specimen (upper right), suspect dentition with celluloid template (lower left), and incisally marked celluloid template comparison with transilluminated tissue (lower right).

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Figure 21.147 Superimposed dental comparisons of hemorrhagic pattern.

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Figure 21.148 Bitemark and suspect dental comparison.

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Figure 21.149 Healing abrasions and suspect dental comparison.

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Figure 21.150 Bitemark on the arm with areas of reference on the excised and transilluminated specimen.

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Figure 21.151 Frontal view of dentition and bitemark comparison.

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Figure 21.152 Occlusal and frontal views of the dentition and bitemark comparison.

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Figure 21.153 Bitemark comparison by superimposition of excised and transilluminated specimen.

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Figure 21.154 Bitemark comparison technique and transillumination.

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References 1. Dorion, R. B. J. 1977. Chairman, Committee for Recommended Methods, AAFS, odontology section, Feb. 1977. 2. Harvey, W. 1976. Dental identification and forensic odontology. London: Kimpton Publishers. 3. Morrison, H. L. 1979. Psychiatric observations and interpretations of bitemark evidence in multiple murders. Journal of Forensic Sciences 24 (2): 492–502. 4. Dorion, R. B. J. 1996. Forensic dentistry in Quebec from 1973 to 1995. Canadian Society of Forensic Science Journal 29 (4): 259–268. 5. Vale, G. L., and T. T. Noguchi. 1983. Anatomical distribution of human bite marks in a series of 67 cases. Journal of Forensic Sciences 28 (1): 61–69. 6. Pretty, I. A., and D. Sweet. 2000. The anatomical location of bite marks and associated findings in 101 cases from the United States. Journal of Forensic Sciences 45 (4): 812–814. 7. ABFO position paper on bitemark workshop no. 4. ASFO News 22 (2): 5. 8. Dorion, R. B. J. 2001. Bitemark project 2000—Objectivity. AAFS Meeting, odontology section, Seattle, WA, Feb. 23, 2001. 9. Johnson, L. T. 2007. NIJ grant MFRC07-06 final report. 10. Johnson, L. T., D. D. Blinka, P. VanScotter-Asbach, and T. W. Radmer. 2008. Journal of Forensic Identification 58 (4): 409. 11. Johnson, L. T., T. W. Radmer, T. S. Wirtz, N. M. Pajewski, D. E. Cadle, J. Brozek, and D. D. Blinka. 2009. QuantificaÂ� tion of the individual characteristics of the human dentition. Journal of Forensic Identification, 59 (6): 609–625. 12. Bush, M. A., R. G. Miller, R. B. J. Dorion, and P. J. Bush. The role of the skin in bite marks, part I: Biomechanical factors and distortion; Miller, R. G., P. J. Bush, R. B. J. Dorion, and M. A. Bush. The role of the skin in bite marks, part II: Macroscopic analysis; Bush, P. J., R. G. Miller, R. B. J. Dorion, and M. A. Bush. The role of the skin in bite marks, part III: Microscopic analysis; Phillips, B. G., P. J. Bush, R. G. Miller, R. B. J. Dorion, and M. A. Bush. The role of the skin in bite marks, part IV: Clothing weave transfer. AAFS, odontology section, Washington, D.C., Feb. 21, 2008. 13. Bush, P. J., R. G. Miller, R. B. J. Dorion, and M. A. Bush. The relationship of uniqueness and resolution in bite mark analysis; M. A. Bush, R. G. Miller, R. B. J. Dorion, and P. J. Bush. The response of skin to applied stress: The influence of force per unit area in bite mark analysis. AAFS, odontology section, Denver, CO, Feb. 20, 2009. 14. Bush, M. A., H. I. Cooper, and R. B. J. Dorion. 2010. Inquiry into the scientific basis for bite mark profiling and arbitrary distortion correction. Journal of Forensic Sciences 55 (4): 976–983. 15. http://www.mcgill.ca/dentistry/conted/forensic/ 16. Dorion, R. B. J., and A. Lauzon. Factors affecting bite mark analysis; Dorion, R. B. J., S. Laforte, M. J. Perron, and M. L. Nielsen. Bite mark research—Antemortem and

postmortem bite marks; Sweet, D. J., and T. E. Newell. ABFO no. 2 photographic scales—Quality assurance is now left to the user. AAFS, odontology section, Seattle, WA, Feb. 24, 2006. 17. Dorion, R. B. J. 2007. Bitemark analysis—Part 1 and 2 results; bitemark research—antemortem and postmortem bite marks: Part two. AAFS, odontology section, San Antonio, TX, Feb. 23, 2007. 18. Desranleau, S., and R. B. J. Dorion. 2009. Bite marks: Physical properties of the ring adhesion to skin. Phase 1. AAFS, odontology section, Denver, CO, February 20, 2009 (Journal of Forensic Sciences, in print March 2011). Desranleau, S., and R. B. J. Dorion. 2010. Bite marks: Physical properties of ring adhesion to skin—Phase 2. AAFS, odontology section, Seattle, WA, Feb. 25, 2010. 19. Dorion, R. B. J. 2010. Bite mark profiling based upon color, UV, and ALI photographic interpretation; Perron, M. J., and R. B. J. Dorion. 2010. Macroscopic and microscopic study of the effects of freezing and thawing on bite marks; Perron, M. J., and R. B. J. Dorion. 2010. Bite marks on a live victim: Data collection, healing process, and loss of details; Desranleau, S., and R. B. J. Dorion. 2010. Bite marks: Physical properties of ring adhesion to skin—Phase 2. AAFS, odontology section, Seattle, WA, Feb. 25, 2010. 20. Phillips, B. G., P. J. Bush, R. G. Miller, R. B. J. Dorion, and M. A. Bush. 2008. The role of the skin in bite marks, part IV: Clothing weave transfer. AAFS, odontology section, Washington, D.C., Feb. 21, 2008. 21. Dorion, R. B. J. 2010. Bite mark profiling based upon color, UV, and ALI photographic interpretation. AAFS, Seattle, WA, Feb. 25, 2010. 22. Perron, M. J., and R. B. J. Dorion. 2010. Macroscopic and microscopic study of the effects of freezing and thawing on bite marks. AAFS, odontology section, Seattle, WA, Feb. 25, 2010. 23. Dorion, R. B. J. 1997. Bitemark computer imaging, enhancement, measÂ�ureÂ�ment, analysis and overlays. AAFS, odontology section, New York, Feb. 21, 1997. 24. Gardner, C. D., H. H. Mincer, O. C. Smith, and S. A. Symes. 1999. Application of epiluminescence microscopy (ELM) to the evaluation of bite marks; Riley, C. K., B. K. Norling, and M. E. Alder. 1999. Dimensional stability and accuracy of a non-traditional modeling material: A pilot study; Gould, G. A. 1999. Bite mark analysis: A device to assist in the orientation of upper and lower arches; Johnson, L. T., V. Dhuru, and G. delCampo. 1999. The accuracy of elastomeric forensic models; Crowley, K. M., R. J. Evans, R. Gillies, M. Bamberg, and N. Kollias. 1999. Identification of saliva on skin using fluorescence spectroscopy; Kim, J. J., and D. Sweet. 1999. Evaluation of the use of ABFO bitemark guidelines in various geographic locations; Perrier, M., B. Horisberger, and P. Mangin. 1999. A bite mark case presentation: Examination and computer imaging analysis; Brzozowski, C. C., L. A. Nawrocki, and B. K. Friedman.

Research, Emerging Technologies, and Recent Developments

1999. A comparison of dimensional stability of excised patterned injuries using various fixatives: A preliminary study; Georget, C. E., and W. T. Baston. 1999. Recording and computerizing superimposition of human bite marks; Dorion, R. B. J. 1999. Knives, tissue resection, preservation and transillumination. AAFS meeting, odontology section, Feb. 1999. 25. Bowers, C. M., and I. A. Pretty. 2000. Critique of the knowledge base for bitemark analysis during the 60s, 70s, and early 80s; Brzozowski, C. C., L. A. Nawrocki, and B. K. Friedman. 2000. A comparative study of materials and methods used for collecting, stabilizing, and preserving excised tissue. AAFS meeting, odontology section, Reno, NV, Feb. 24, 2000. 26. Wiley, B. R., and R. D. Rawson. 2001. Classifying bitemark severity—A proposed modification of forensic odontological nomenclature; Pretty, I. A., and D. Sweet. 2001. The effectiveness of bitemark overlays; Valenzuella, A., S. Martin de las Heras, D. Fuentes, and J. C. Torres. 2001. Production of bitemark comparison overlays from 3-D scanned images; Senn, D. R., M. E. Alder, P. C. Brumit, and M. White. 2001. Scanning electron microscopy and digital imaging software in bite mark analysis: Technique in case report; Sweet, D. 2001. Blind testing as a scientific protocol—Use of a dental lineup for bitemark suspects. AAFS meeting, odontology section, Seattle, WA, Feb. 23, 2001. 27. Firestone, S. R., and B. K. Friedman. 2002. Objective bitemark analysis using an electronic occlusal diagnostic system; Weems, R. A., and J. H. Embry. 2002. Dynamic courtroom presentation of bitemark evidence via digital overhead camera and LCD projector; Parks, E. T. 2002. Bitemark analysis utilizing the computer pitfalls and brick walls; Lasser, A. J., A. J. Warnick, and G. M. Berman. 2002. A unique way to analyze bite marks using 3-D laser scanners and comparative software; Johansen, R. J., and M. Bowers. 2002. Digital analysis of evidence photographs (bitemark): Automated rectification of photographic distortion, resizing to life size, and rotation of images; Taylor, R. V., S. A. Blackwell, M. U. Yoshino, C. L. Ogleby, T. Tanijiri, and J. G. Clement. 2002. Three-dimensional noncontact morphometric comparisons of human dentitions with simulated human bite marks. AAFS meeting, odontology section, Atlanta, GA, Feb. 15, 2002. 28. McCormack, O., R. C. Hall, I. A. Pretty. 2003. Wound contraction and older bite mark injuries: Aspects of interest to odontologists; Avon, S. L., R. E. Wood, and B. Blenkinsop B. 2003. An in vivo porcine model of contusive bite mark injuries in human bite mark analysis; Tewes, W. 2003. Topographic mapping to improve objectivity in bite mark analysis for Adobe Photoshop hollow volume construction; Firestone, S. R., and B. K. Friedman. 2003. Objective bite mark analysis using an electronic occlusal diagnostic system. Part II; Brumit, P. C., and J. McGivney. 2003. A mathematical approach to bitemark analysis using Bite2000 software. AAFS, odontology section, Chicago, IL, Feb. 21, 2003.

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29. Freeman, A. J., D. R. Senn, and D. A. Arendt. 2004. A survey of the etiology, anatomical location, victim demographics, and legal disposition in 250 bite mark cases involving human victims; McNamee, A. H., D. Sweet, and I. A. Pretty. 2004. A comparative reliability analysis of computer-generated bitemark overlays; Tonn, E. M., D. J. Long, and D. Dechant. 2004. A comparison of intercanine widths among various animals and humans; Williams, R. G. 2004. Stereometric analysis of a human bite mark; Gould, G. A. 2004. Bitemark analysis: Findings of an exercise designed to measure accuracy and reliability; Brumit, P. C., J. McGivney, and B. A. Schrader. 2004. A mathematical approach to bite mark analysis using BiteMark 2003 software—Phase two; Souviron, R. R. 2004. Pattern injury bite mark investigative protocol. AAFS, odontology section, Dallas, TX, Feb. 21, 2004. 30. Murmann, D. C., D. R. Senn, P. C. Brumit, and B. A. Schrader. 2005. A comparison the animal jaws and bite mark patterns; Gould, G. T., N. T. Pham NT, and D. R. Senn. 2005. Bitemark analysis: Additional investigations of accuracy and reliability; Brzozowski, C., and J. B. McGivney. 2005. Determining the accuracy and reproducibility of Adobe Photoshop overlay techniques using WinBite software. AAFS, odontology section, New Orleans, LA, Feb. 25, 2005. 31. Van der Velden, B., M. Spiessens, and G. Willems. 2006. Bitemark comparison and analysis using image perception technology; Pretty, I. A., and R. C. Hall. 2006. Development and validation of a human bite mark severity and significance scale; Giordano, J. J., D. R. Senn, B. A. Schrader, and P. C. Brumit. 2006. The significance of inter-canine distance in bitemark analysis: A critical analysis of juvenile versus adult dimensions; Dorion, R. B. J., and A. Lauzon. 2006. Factors affecting bite mark analysis; Dorion, R. B. J., S. Laforte, M. J. Perron, and M. L. Nielsen. 2006. Bite mark research—Antemortem and postmortem bite marks; Sweet, D. J., and T. E. Newell. 2006. ABFO no. 2 photographic scales—Quality assurance is now left to the user. AAFS, odontology section, Seattle, WA, Feb. 24, 2006. 32. Lettie, J. R., P. C. Brumit, B. A. Schrader, and D. R. Senn. 2007. Determination of bite force; Lewis, J. M., P. C. Brumit, B. A. Schrader, and D. R. Senn. 2007. Comparative analysis of hollow volume overlays fabricated in Adobe Photoshop; Dorion, R. B. J. 2007. Bitemark analysis—Part 1 and 2 results; Dorion R. B. J. 2007. Bite mark research—Antemortem and postmortem bite marks—Part 2. AAFS, odontology section, San Antonio, TX, Feb. 23, 2007. 33. Metcalf, R. D., P. C. Brumit, B. A. Schrader, and D. R. Senn. 2008. On the uniqueness of human dentition; Johnson, L. T., T. S. Wirtz, T. W. Radmer, and D. Cadle. 2008. The verdict is in: Can dental characteristics be quantified?; Freeman, A. J., and T. J. David, 2008. The ABFO no. 2 scale: A 20 year retrospective study: The history and accuracy of the ABFO no. 2 scale; Pace, W. 2008.

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Hydraulic forces as the cause of human bitemark injury patterns; Pace, W. 2008. Three methods of measuring the force of a human bite; Scheper, R. J., P. C. Brumit, B. A. Schrader, and D. R. Senn. 2008. Demographic variation effects on human bite force; Avon, S. L., and R. E. Wood. 2008. Determination of the accuracy of decision making in the interpretation of bite mark analysis; Swyter, S., P. C. Brumit, B. A. Schrader, and D. R. Senn. 2008. Comparative analysis of hollow volume overlays fabricated using Adobe Photoshop; Dondero, H. J. A. 2008. Geometric analysis of the inherent inaccuracies found in linear measurement of curved bite mark surfaces; Bush, M. A., R. G. Miller, R. B. J. Dorion, and P. J. Bush. 2008. The role of the skin in bite marks, part I: Biomechanical factors and distortion; Miller, R. G., P. J. Bush, R. B. J. Dorion, and M. A. Bush. 2008. The role of the skin in bite marks, part II: Macroscopic analysis; Bush, P. J., R. G. Miller, R. B. J. Dorion, and M. A. Bush. 2008. The role of the skin in bite marks, part III: Microscopic analysis; Phillips, B. G., P. J. Bush, R. G. Miller, R. B. J. Dorion, and M. A. Bush. 2008. The role of the skin in bite marks, part IV: Clothing weave transfer. AAFS, odontology section, Washington, D.C., Feb. 21, 2008. 34. Tuceryan, M. T., H. L. Blitzer, L. Fang, E. T. Parks, J. A. Platt, and G. Flora. 2009. Use of 3-D imaging and mathematics in assigning the probability of a match between a dental model and a bite mark; Bush, P. J., R. G. Miller, R. B. J. Dorion, and M. A. Bush. 2009. The relationship of uniqueness and resolution in the bite mark analysis; Bush, M. A., R. G. Miller, R. B. J. Dorion, and P. J. Bush. 2009. The response of skin to applied stress: The influence of force per unit area in bite mark analysis; Dashkow, S., M. A. Bush, and P. J. Bush. 2009. A study of familial bite marks: Can we discern the uniqueness?; Dalle Grave, C. M., A. A. Da Luz Dos Santos, P. C. Brumit, B. A. Schrader, and D. R. Senn. 2009. Three-dimensional analysis and comparison of human anterior teeth and experimentally created bite mark depressions; Desranleau, S., and R. B. J. Dorion. 2009. Bite marks: Physical properties of the ring adhesion to skin—Phase 1. AAFS, odontology section, Denver, CO, Feb. 20, 2009. 35. Dorion, R. B. J. 2010. Bite mark profiling based upon color, UV, and ALI photographic interpretation; Perron, M. J., and R. B. J. Dorion. 2010. Macroscopic and microscopic study of the effects of freezing and thawing on bite marks; Perron, M. J., and R. B. J. Dorion. 2010. Bite marks on a live victim: Data collection, healing process, and loss of details; Desranleau, S., and R. B. J. Dorion. 2010. Bite marks: Physical properties of ring adhesion to skin—Phase 2; McGivney, J. 2010. Using fractal dimension to classify human dentitions; Penola, D. T. 2010. Mammelons and the diastemas in adult population: Frequency and implications in bite mark evidence; Bush, M. A., H. I. Cooper, and R. B. J. Dorion. 2010. An inquiry into the scientific basis for bite mark profiling and

arbitrary distortion correction; Bush, M. A., P. J. Bush, and H. D. Sheets. 2010. Description of the human dentition using three-dimensional landmarks: An investigation of similarity and match rates; Brzowski, C., L. A. Nawrocki, P. Ho, H. D. Sheets, P. J. Bush, and M. A. Bush. 2010. Similarities of the human dentition in an open population using two-dimensional geometric morphometric analysis; Sheets, H. D., P. J. Bush, and M. A. Bush. 2010. The use of geometric morphometric methods in forensic odontology: Overview analysis of the human dentition; Maness, H., P. C. Brumit, B. A. Schrader, and D. R. Senn. 2010. The effect of dental model placement on the image distortion during scanning for overlay production in digital bite mark analysis; Maness, H., P. C. Brumit, B. A. Schrader, and D. R. Senn. 2010. Use of common orthodontic measurements to investigate the uniqueness of the human dentition and biting complex; Fancher, J. P., P. C. Brumit, B. A. Schrader, and D. R. Senn. 2010. An investigation of the uniqueness of the human dentition. AAFS, odontology section, Seattle, WA, Feb. 25, 2010. 36. Dinkel, E. H., Jr. 1974. The use of bite mark evidence as an investigative aid. Journal of Forensic Sciences 19:3. 37. Vale, G. L., R. F. Sognnaes, G. N. Felando, and T. T. Noguchi. 1976. Unusual three-dimensional bite mark evidence in a homicide case. Journal of Forensic Sciences 21:3. 38. Morrison, H. L. 1979. Psychiatric observations and interpretations of bite mark evidence in multiple murders. Journal of Forensic Sciences 24:2. 39. Glass, R. T., E. E. Andrews, and K. Jones, III. 1980. Bite mark evidence: A case report using accepted and new techniques. Journal of Forensic Sciences 25:3. 40. Vale, G. L., and T. T. Noguchi. 1983. Anatomical distribution of human bite marks in a series of 67 cases. Journal of Forensic Sciences 28:1. 41. Karazulas, C. P. 1984. The presentation of bite mark evidence resulting in the acquittal of a man after serving seven years in prison for murder. Journal of Forensic Sciences 29:1. 42. Krauss, T. C. 1984. Photographic techniques of concern in metric bite mark analysis. Journal of Forensic Sciences 29:2. 43. Krauss, T. C., and S. C. Warlen. 1985. The forensic science use of reflective ultraviolet photography. Journal of Forensic Sciences 30:1. 44. Bernstein, M. L. 1985. Two bite mark cases with inadequate scale references. Journal of Forensic Sciences 30:3. 45. David, T. J. 1986. Adjunctive use of scanning electron microscopy in bite marks analysis: A three-dimensional study. Journal of Forensic Sciences 31:3. 46. Rawson, R. D., G. L. Vale, N. D. Sperber, E. E. Herschaft, and A. Yfantis. 1986. Reliability of the scoring system of the American Board of Forensic Odontology for human bite marks. Journal of Forensic Sciences 31:4. 47. Rawson, R. D., G. L. Vale, E. E. Herschaft, N. D. Sperber, and S. Dowell. 1986. Analysis of photographic distortion in bite marks: A report of the Bite Mark Guidelines Committee. Journal of Forensic Sciences 31:4.

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Experimental Bitemarks and Histology Michelle Houde

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Contents 22.1 Introduction 22.2 Normal Porcine Skin Histology 22.2.1 The Epidermis 22.2.2 The Dermis 22.2.3 The Hypodermis 22.3 Microscopic Examination of Bitemarks on the Fresh Piglet 22.3.1 The Architecture of a Bitemark 22.3.2 Histologic Lesions 22.3.3 Lividity 22.3.4 Age and Vitality 22.4 Microscopic Examination of Bitemarks on Frozen Pigskin 22.4.1 Piglet No. 8 22.4.2 Freezing Artifacts 22.4.3 Principal Observations 22.5 Microscopic Examination of Human Bites 22.5.1 Bitemark on a Young Adult 22.5.2 Bitemark on a Young Child 22.6 Conclusion Acknowledgments References

22.1â•…Introduction Studies by Meyer et al. [1], Lavker et al. [2], and Sullivan et al. [3] have all shown that pigskin has several morphological and functional characteristics comparable to human skin. The availability, the cost, and the ease of handling piglets make the pig the animal of choice for the study of bitemarks. Under the direction of Dr. Robert Dorion, forensic odontologist at the Laboratoire de Sciences Judiciaires et de Médecine Légale in Montreal, a team of dentists undertook a macroscopic study of bitemarks on piglets over a number of years. The piglets were bred from Landrace and Yorkshire sows combined with Duroc boars, making them Duroc (50%), Landrace (25%), and Yorkshire (25%). The average age of the piglets was approximately 8 weeks and they weighed from 5 to 10 kg. Without being the subject of a specific study, certain bites were randomly chosen for microscopic examination in order to study the lesions caused by this type of trauma, the contribution of lividity, and the changes observed in antemortem and postmortem bites. Because Canada is a northern country, Drs. Dorion and Marie-

433 433 433 434 435 436 436 437 437 438 440 440 440 441 442 442 443 446 451 452

Josée Perron wanted to include the effects of climatic changes (freezing in particular) in the study of bitemarks. Thus, the studied bites were on a 9-month frozen piglet. The microscopic examination of these bites brought about certain observations and interesting conclusions.

22.2â•…Normal Porcine Skin Histology Like human skin, porcine skin is composed of three layers whose thickness varies according to site. As in humans, the skin consists of epidermis (A), dermis (B), and hypodermis (C), with fascia (D), and muscle (E) (FigureÂ€22.1, right). 22.2.1â•…The Epidermis The skin is a stratified, keratinized epithelium made up of a superficial compact layer called cornified layer (stratum corneum; A), a granular layer (stratum granulosum; B), a spinous layer (stratum spinosum; C), and a basal layer (stratum basale; D) (FigureÂ€22.2, left). Certain authors (Vardaxis et al. [4], Marcarian and Calhoun [5],

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition A B

C 2.0 mm E

D

2.0 mm

Figure 22.1â•‡ Skin from the lumbar region (2×, HPS; left). Skin from the thigh (2×, HPS; right).

A B C D

F

E

G

200 µm

Figure 22.2â•‡ Skin from withers showing the epidermis with its different layers, epidermal ridges, and papillary dermis (60×, HPS; left). Skin from the lumbar region: There is no clean-cut demarcation between the papillary and the reticular dermis (20×, HPS; right).

and Smith and Calhoun [6]) do not distinguish the basal layer and the spinous layer. For them, it is a single layer: stratum germinativum. The keratinocytes are the principal cellular component of the epidermis. The inferior border of the epidermis is corrugated. It forms epidermal ridges, more or less broad and long, that alternate with the dermal papillae (E). The basal layer (stratum basale) is the deepest layer. It is made up of a layer of cuboidal or columnar cells attached to the basement membrane. Within this layer, which is mitotically active, skin regenerates. The spinous layer (stratum spinosum) bears its name because of the cells of which it is composed. Indeed, the keratinocytes have intercellular bridges that resemble a crown of spines around each cell. This histological aspect is quite visible when intercellular spaces widen. The thickness of this layer varies according to the anatomical site. The cells are polygonal in shape and have more cytoplasm than the basal layer; as the surface is approached, they become flattened. The granular layer (stratum granulosum) is made up of one to three flattened nucleated layers of keratinocytes whose cytoplasm contains basophilic granules of keratohyaline. Finally, on the surface of the skin, there is the corneum layer.

This layer is prominent and compact on the snout. It consists of several layers of lengthened dead cells, flattened and without a nucleus. 22.2.2â•…The Dermis The dermis is made up of two layers without clear separation: the papillary layer (stratum papillare; F) and the reticular layer (stratum reticulare; G) (FigureÂ€22.2, right). With its fine elastic and collagen fibers, the connective tissue of the papillary dermis (F) presents a more delicate appearance than the reticular dermis (G) (FigureÂ€22.2, right), where the elastic fibers (H; FigureÂ€22.3, left), with coarser and intermingled collagen fibers, create a denser connective tissue. Between collagen fibers, there are many scattered fibroblasts (I). One also finds eosinophils (J) and mast cells (K) (FigureÂ€ 22.3, right). The latter are especially localized around the vessels of the papillary dermis [5]. In the dermis, one finds hair follicles (left) (Figure 22.4, left), sweat glands, blood vessels, and nerves. The hair follicles are isolated or in groups of two to three. The bulbs of the largest follicles are located either in the major part of the reticular dermis or in the higher portion of

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H

H

J

I

K

Figure 22.3â•‡ Thigh skin: elastic fibers in papillary and reticular dermis (40×, Weigert-HPS; left). Skin from withers: perivascular mast cell, eosinophil, and fibroblast (60×, HPS; right).

L

M 200 µm

Figure 22.4â•‡ Flank skin: hair follicle in the hypodermis (4×, HPS; left). Skin from the leg: hair follicle and rudimentary sebaceous gland (20×, PAS; right).

the hypodermis, where the adipose tissue extends outward in the dermis and forms dome-like architecture around the bulbs of the follicles [7,8]. The sebaceous glands attached to the hair follicles (M; FigureÂ€22.4, right; FigureÂ€22.5, right) are rather rudimentary and the excretory duct empties into the superior portion of the hair follicle. Though distinct, the apocrine sweat glands (Figure 22.5, right) are associated wherever hair follicles are present, usually in a one-to-one ratio. The secretory coil rests in the deep reticular dermis or at the dermo-hypodermal junction. The cuboidal or columnar secretory epithelium may protrude into the lumen or may be flattened and is externally bordered by myoepithelial cells. The ducts of the glands are arranged parallel to the hair and open to the surface of the epidermis independently (N; FigureÂ€22.5, right) near the follicle orifice [1,5,7,8].

The vascularization of piglet skin is similar to that of humans. There are vascular networks in the middle and deep portions of the subepidermis and dermis. However, the subepidermal vascular plexus is less dense and the perifollicular and periglandular areas are less vascularized than those in humans [1,4,7]. 22.2.3â•…The Hypodermis As in humans, thermal insulation in the pig is reliant on adipose tissue rather than on hair or fur. The adipocytes or fat cells of the hypodermis are contained in pockets (O; FigureÂ€ 22.6, left) delimited by elastic and collagen fibers. The formation of these chambers (in German, Fettkammern) depends on the age and gender of the animal [1,4]. This layer of subcutaneous fat also contains

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R

M 200 µm

500 µm

Figure 22.5â•‡ Skin from the leg: apocrine sweat glands (40×, PAS; left). Skin from the abdomen: excretory duct of apocrine gland arranged parallel to the hair follicle (10×, PAS; right).

O

P

2.0 mm

Figure 22.6â•‡ Abdominal skin: pocket formation in subcutis (2×, HPS; left). Piglet photos, dependent and nondependent sides. The sites where the bitemarks are identified on the skin (right).

blood vessels and nerves. According to the site and the depth of the tissue excision, under the subcutis one can find a layer of connective tissue, the fascia, or skeletal muscle (P; FigureÂ€22.6, left).

22.3â•…Microscopic Examination of Bitemarks on the Fresh Piglet Microscopic examination was made of antemortem bitemarks, ranging from 1 to 53 minutes, on 11 piglets. The bites were located on various places of the body and dependent and nondependent sides in order to evaluate the influence of lividity (Q; FigureÂ€ 22.6, right) on the bites. One to three sample excisions were analyzed from each bite (FigureÂ€22.7). After fixation in 10% formalin and paraffin preparation, each block was cut and prepared with standard staining solutions—namely, HPS (hematoxylin, phloxine, and saffron). The changes observed on several slides appeared insufficient compared to the macroscopic anomalies; cuts on three levels of each block were carried out (FigureÂ€22.7). This enabled the observer to highlight

the various layers of the skin and allowed for an appreciation of the extent of histological damage. 22.3.1â•…The Architecture of a Bitemark All of the studied bitemarks had a microscopic architecture that enabled orientation of the specimen. Indeed, the compression of the various layers of skin reflected the direction of movement of the jaw at the time of bitemark infliction. This resulted histologically as an acute angle of compressed tissue between the skin surface and the depth of the hypodermis. Thus, in a cutaneous excision, the site of compression and indentation on the surface of the skin was always on the external side (right), whereas the compressed hypodermis was on the internal side (left) (FigureÂ€22.7, right; FigureÂ€22.8, left). If one refers to the macroscopic aspect of the bitemark, the external side was the convex side of the dental arch, whereas the internal side corresponded to the concave side of the dental arch. This picture was all the more obvious as the trauma inflicted increased. Conversely, when the histological changes were minor, the identification of the compression zone in the hypodermis allowed

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Figure 22.7â•‡ Tissue excision from a bite site (left). Identification from the internal and external aspects of the cutaneous specimen lifted from a leg bitemark (right).

S

S

R

R 2.0 mm

2.0 mm

Figure 22.8â•‡ Skin from the leg, nondependent side: compression and focal indentation of the epidermis (2×, HPS; left, and 20×, HPS; right).

for back sourcing the area of skin compression (going toward the surface of the skin). If this was not identified on the slide, successive slides permitted finding the epidermal lesion and subsequently orienting the specimen. 22.3.2â•…Histologic Lesions The exerted force and the anatomical site are factors that influence the extent and the importance of the cutaneous lesions. The damage that can be observed in the various layers of the skin includes the following: • Epidermis: indentation of the surface, partial or total erosion, compression of the superficial layers or of the entire thickness of the epiderÂ�mis (FigureÂ€ 22.10, right), necrosis of the epidermis (FigureÂ€ 22.9, left), cellular edema (Figure 22.9, right) • Dermis: cellular and interstitial edema in the papillary dermis (FigureÂ€22.11, left), focal edema in the reticular dermis (FigureÂ€ 22.11, right), congestion of the blood capillaries of the superior dermis on both sides of the zone of indentation with compression of the skin, discrete focal interstitial hemorrhage in the reticular dermis

• Hypodermis: compression (FigureÂ€ 22.12, left), more or less important interstitial hemorrhage, interstitial edema, dilation and congestion of the blood vessels in the zone of hemorrhage (FigureÂ€22.12, right), perivascular nuclear dust, rupture of the fat cells • Skeletal muscle: hemorrhage, focal necrosis (FigureÂ€22.13, right) of skeletal muscular cells 22.3.3â•…Lividity When blood circulation ceases at the time of death, stagnant blood in the blood vessels settles by gravity toward the surface closest to the ground. This phenomenon is visible on the skin, which generally takes on a purplish color. The localization of lividity is a function of the position of the body. Thus, the piglet that rests several hours on its right side after death will develop lividity on this side, except at the places supported against a surface. The blood vessels in these zones are under passive pressure— the body’s own weight—and the skin remains pale. Certain authors have observed the presence of dilated and congestive blood vessels in bitemarks located on the dependent side [9]. We did not find that to be the case in our samples. In fact, in all the bitemarks

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200 µm

Figure 22.9â•‡ Skin from the anterior thorax, nondependent side: compression and necrosis of the epidermis (long arrow). Focal loss of the horny layer (short arrow) (40×, HPS; left). Skin from the leg, nondependent side: compression and cellular edema of basal layer of the epidermis (long arrow). Congestion of the vessels of the upper dermal layer (60×, HPS; right).

Figure 22.10â•‡ Skin from the thorax, nondependent side: vascular congestion and extravasation of the red blood cells in the superior dermis (60×, HPS; left). Skin from the leg, nondependent side: compression of the dermis (60×, HPS; right).

500 µm

Figure 22.11â•‡ Skin from the leg, nondependent side: edema of the papillary dermis (60×, HPS; left). Skin from the neck, nondependent side: site of severe edema in the reticular dermis (10×, HPS; right).

sampled, regardless of side, a certain number of blood vessels—small ones and larger-diameter ones, dilated and congested—were always in the hemorrhagic and compressed zone. In only one sample did we find a large dilated and congested blood vessel in the deep hypodermis external side (FigureÂ€22.14, left). This specimen was identified as a bite on the shoulder—the dependent side of the animal. Thus, the aspect of the blood vessels did

not prove to be a discriminating factor to determine the side of lividity. 22.3.4â•…Age and Vitality All cutaneous examined specimens presented hemorrhages of varying degrees and a more or less marked edema. The hemorrhages were mainly in the hypodermis.

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500 µm

Figure 22.12 Skin from the hip, nondependent side: compression of the hypodermis (10×, HPS; left). Skin from the thigh, nondependent side: congestion of blood vessels of the hypodermis (20×, HPS; right).

200 µm

Figure 22.13 Skin from the leg, nondependent side: extravasation of red blood cells in the hypodermis (20×, HPS; left). Skin from the anterior thorax, nondependent side: focal necrosis of skeletal muscle cells and extravasation of red blood cells (20×, HPS; right).

500 µm

200 µm

Figure 22.14 Skin from the shoulder, dependent side: congestive and dilated blood vessel in the hypodermis, external

side (10×, HPS; left). Skin from the hip, nondependent side: inflammatory infiltrate around a hair follicle (40×, HPS; right).

When the trauma was severe and created important damage, there were also rare small areas of extravasated red blood cells in the superior dermis. The presence of extravasated red blood cells in tissue following blood vessel rupture in a contusion is, most of the time, an indication of vitality. However, it is possible to produce a contusion after death when certain conditions are combined (fluidity of blood, sufficient force of impact, gravity). All of the specimens examined

came only from antemortem bitemarks. Examination of postmortem bites remains to be done. However, in light of our observations, the study of the bitemark hemorrhage requires that the entire thickness of the hypodermis be taken into account, especially when the trauma is minor. The presence of edema is indicative of a vital reaction. The presence of edema was variable between different specimens and the same specimen. Vacuoles of

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 22.15â•‡ Skin from the anterior thorax, nondependent side: neutrophils in the hypodermis (Figure 22.28; 60×, HPS; left) and several neutrophils around the small blood vessels in the superior dermis (Figure 22.29; 60×, HPS; right).

edema were generally observed in the papillary dermis. Intracellular edema could be seen in the keratinocytes of the skin and, more rarely and in severe trauma, sites of large vacuoles occupying a part or all of the thickness of the reticular dermis, which caused marked swelling of the skin surface. The inflammatory reaction is an indisputable sign of the vitality of a lesion. This process is complex and, to date, the age of a wound according to the histological, biochemical, histochemical, and enzymatic changes observed in such a reaction cannot be determined with precision. From the histological point of view, this is all the more true the closer the lesion is inflicted to the moment of death. In the current study, bitemarks were inflicted from 1 minute to 53 minutes before death. In certain specimens, a preexisting inflammatory reaction associated with the hair follicles could be identified (FigureÂ€22.14, right). In a bitemark from the anterior thorax nondependent side made 41 minutes before death, a small group of polynuclear neutrophils in the hypodermis and some neutrophils around blood vessels of the upper dermis were observed in an area outside the hemorrhagic zone (FigureÂ€22.15). On the succeeding cuts from these blocks, there was no obvious preexisting inflammatory lesion to the bitemark. Such histological changes were not identified on the other slides, regardless of the age of the bites.

22.4â•…Microscopic Examination of Bitemarks on Frozen Pigskin 22.4.1â•…Piglet No. 8 Among the group of piglets used in this 4-year study, one was used to evaluate the effects of freezing on the bites. The times between the antemortem bites varied

from 82 minutes before death until death, and some were inflicted postmortem. Otherwise, the same protocol was used for bitemark infliction and postinfliction, but then the animal was frozen for 9 months. At the end of this period, the bites were excised using the Dorion type V technique described elsewhere in this book. After photographs and macroscopic examination were done, one to four representative areas were excised from the bitemarks on the dependent sides and six from the nondependent sides; they were processed for microscopic examination. The results were partially presented at the American Academy of Forensic Sciences annual meeting in February 2010 [10]. The mechanisms that underlie cellular and tissue deterioration in bitemarks in the frozen piglet were the main theme. The following section will describe the principal histological aspects of these bitemarks following prolonged freezing. 22.4.2â•…Freezing Artifacts The intranuclear, intracellular, and interstitial vacuoles are observed in all layers and structures of the skin (FiguresÂ€22.16 and 22.17). They are isolated, in groups, or confluent. The red blood cells are autolyzed, thereby eliminating any trace of hemorrhage, which would have indicated an antemortem infliction. The cellular components are often badly preserved, with hyperchromatic and shrunken nuclei; this prevents accurate cellular identification. Moreover, the compression of cells around structures like the blood vessels and the hair follicles gives the impression of hypercellularity seen in an inflammatory reaction (FigureÂ€22.18). The various layers of skin pile up more than the single effect of compression caused by the bite, but they are compounded by dehydration and cellular lysis. The cutaneous appendages and the blood vessels of the

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Figure 22.16â•‡ Skin from the hip, nondependent side: intranuclear vacuoles in the keratinocytes of the epidermis

(60×, HPS; left). Skin from the posterior abdomen, nondependent side: vacuoles in the papillary and reticular dermis (60×, HPS; right).

200 µm

Figure 22.17â•‡ Skin from the hip, nondependent side: vacuoles in the hair follicles (20×, HPS).

2.0 mm

200 µm

Figure 22.18â•‡ Skin from the back, nondependent side, 66 minutes prior to death: compression of the hypodermis and red blood cell absence in the compressed zone (4×, HPS; left, and 40×, HPS; right).

skin lose their rounded contours and become angular (FigureÂ€ 22.19, right). When there is compression with surface indentation of the skin or laceration of tissue, this creates a nest favorable for the postmortem proliferation of bacteria.

22.4.3â•…Principal Observations The microscopic architecture of a bitemark—namely, the compression of all the layers of skin at right angles starting from the point of compression or indentation—is much more obvious in the frozen piglet. This

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200 µm

200 µm

Figure 22.19â•‡ Skin from the back, dependent side, 41 minutes before death: perivascular hypercellularity (40×, HPS; left). Abdominal skin, dependent side, 3 hours 40 minutes after death: perivascular hypercellularity (40×, HPS; right).

200 µm

Figure 22.20â•‡ Skin from the shoulder, nondependent side: The apocrine glands and the hair follicle are flattened and the

contours angular (20×, HPS; left). Skin from the back, nondependent side: compression of elastic and collagen fibers of the hypodermis and disappearance of the red blood cells at the compression site (60×, HPS; right).

is explained by the disappearance of the red blood cells and the compression of tissue, among other things (see FigureÂ€22.20). The hemolysis of the red blood cells makes it impossible to see the congestive dilated blood vessels, whether in the middle of the compression zone or outside this area. On a specimen taken from the dependent side, a dilated vessel was found in the hypodermis. In another specimen, on the dependent side as well as the nondependent side, blood vessels with angulated contours and opened lumen could be seen. Lastly, regardless of the side of the animal, there were several blood vessels with sagging walls. Thus, the congestive and dilated blood vessels, which, according to certain authors, are observed on the dependent side, are absent in frozen piglet. As for the dilated blood vessels, we have only identified one of them in the sample from the dependent side of the animal. In all other specimens, it was not possible to draw any conclusions regarding blood vessels (see FigureÂ€22.21). The vitality of a lesion based on the tissue presence of hemorrhage also proved impossible to determine. As for the inflammatory reaction, in the absence of skin controls

coming from the same animal and taking into account the degenerated aspect of the cells around the blood vessels, we could not rule on the presence or absence of inflammatory reaction, regardless of the time between the bites and death (FigureÂ€22.22, left). However, this was not the case when there was a well developed preÂ�existing inflammatory reaction, as in the example from a posterior thigh bitemark in FigureÂ€22.22 (right). With regard to the intracellular and intratissular vacuoles, some of them are undoubtedly the result of edema caused by antemortem bites. However, the vacuoles that are freezing artifacts are numerous and at the same places, so it is impossible to draw any conclusions.

22.5â•…Microscopic Examination of Human Bites 22.5.1â•…Bitemark on a Young Adult The external examination of the corpse of a young homicide victim revealed a bite on the external surface of the right arm. The odontological expertise highlighted the hemorrhagic intensity following excision with the

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200 µm

200 µm

500 µm

Figure 22.21â•‡ Skin from the neck, dependent side: dilated blood vessel in the hypodermis. No visible red blood cells (20×, HPS; left). Skin from the posterior back, dependent side: presence of nondilated blood vessels, empty of red blood cells (20×, HPS; right).

200 µm

Figure 22.22â•‡ Skin from the shoulder, nondependent side: presence of nondilated blood vessels, empty of red blood cells. (20×, HPS; left). Skin from the posterior thigh, dependent side: perifolliculitis (10×, HPS; right).

Dorion type V technique. FigureÂ€ 22.23 illustrates the bitemark with different photographic techniques. Figures 22.24 and 22.25 depict preservation techniques as well as the hemorrhage and the transilluminated specimen. Three histological specimens were excised and prepared for microscopic examination from the bite site (FigureÂ€22.25, left). On the HPS stained slides, one could easily identify the hemorrhage, mainly in the subcutaneous fat, even at low power (FigureÂ€ 22.26). The extravasated red blood cells infiltrated the adipocytes and the conjunctive septa (FigureÂ€ 22.27, left). In the zones where the hemorrhage was less intense, there was interstitial edema. Also notice the coalescence of small groups of fragmented adipocytes. The hemorrhage observed in the reticular dermis was in the form of extravasated red blood cells around the blood vessels,

whereas in the deep dermis, as in the C histologic sample (FigureÂ€22.25, left), the hemorrhage was more diffuse. On the surface of the skin, there were zones of erosion with loss of the corneal layer (FigureÂ€ 22.28, left). One also could identify the indentation produced by compression of the skin (FigureÂ€ 22.28, right). The ecchymotic component of this bite was very important. Inflammatory cells were not present. 22.5.2â•…Bitemark on a Young Child On the body of an infanticide victim, three bites were identified. They were located on the posterior surface of the left leg and on both arms. The macroscopic aspect of these lesions, as well as the transilluminated tissue, is illustrated in FiguresÂ€22.29–22.31.

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Figure 22.23â•‡ A color (upper left, upper right), ALI (lower left), and UV photograph (lower right) of an arm that has been “black and white” enhanced with Photoshop®.

From the start, with the macroscopic examination it was obvious that some of the bites on the right arm (FiguresÂ€22.29 and 22.31, upper left and lower left) presented with a combination of new and older bites. These observations were confirmed microscopically. FigureÂ€ 22.32 contains zones where the skin was hyperplastic and hyperkeratotic. In the center of this specimen, there was a zone of indentation covered with regenerated skin (FigureÂ€ 22.32, left). On one side of this depression, a second zone of regenerated skin was found. The subjacent papillary dermis contained dilated and congestive blood vessels accompanied at times by extravasated red blood cells (FigureÂ€22.33, right). In the reticular dermis, there was a light perivascular infiltrate of lymphocytes and histiocytes as well as some neutrophils. Deeper in the widened conjunctive septa was a proliferation of fibroblasts in the presence of lymphocytes, macrophages, and some neutrophils. Areas of fat necrosis were noted in the hypodermal fat and in the presence of small clusters of spumous macrophages (FigureÂ€ 22.34, right). The lower border of this cutaneous specimen showed areas of hemorrhage, fibrin, and a mixed inflammatory cell infiltrate with a predominance of mononuclear cells (FigureÂ€22.35, left). As for specimen B (FigureÂ€ 22.37, left), the skin presented with two regions of epithelial regeneration

separated and bordered on both sides by hyperplastic and hyperkeratotic skin that, contrary to specimen A (FigureÂ€ 22.36, right), was irregularly pigmented. The deep dermis and the hypodermis were hemorrhagic and contained fibrin, small fibrinous thrombi, and a mixed inflammatory infiltrate composed of degenerated neutrophils and lymphocytes (FigureÂ€22.36, left). Two histology specimens were taken from the leg bite. At low magnification, a more important hypodermic hemorrhage was visible in specimen A compared to B, as well as the presence of subcorneal blisters in the former (FigureÂ€22.37, right). Under higher magnification, the floor of the subcorneal blister consisted of partially necrotic epidermis (FigureÂ€ 22.38, left). Adjacent to the large blister, there were some small centers of necrosis throughout the entire thickness of epidermis, as well as isolated necrotic keratinocytes. Within the dermis, the blood vessels were congested and there were some focal areas of extravasated red blood cells. In addition, there was a beginning of the cellular inflammatory reaction with margination of the neutrophils in certain blood vessels (FigureÂ€22.38, right); at other places, the neutrophilic infiltrate was in the perivascular interstitium (FigureÂ€22.39, left).

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Figure 22.24â•‡ Bitemark impression of the previous arm (upper left), ring placement (upper right), excision (center left, center right, lower left), and transillumination (lower right).

Figure 22.25â•‡ The previous excised arm bitemark with specimen removal for histological examination (left). A massive amount of hemorrhage within the fat tissue can be seen on the underside.

The amount of hemorrhage in the subcutaneous fat was significant and was accompanied by fibrin deposits (FigureÂ€22.39, right). Necrotic adipocytes could be noted here and there. As for specimen B, a zone with a small depression of compressed skin was found. The dermis was unremarkable and, in the hypodermis, the hemorrhage was mild.

The three cutaneous specimens of the bite on the left arm showed hemorrhage in the subcutaneous fat accompanied by an acute inflammatory reaction. Each one of them was centered on a recent epidermal lesion. In specimen A, there was a central area of necrosis involving the entire thickness of the skin with adjacent

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Figure 22.26â•‡ Epidermis of the arm specimen A: hemorrhage in subcutaneous fat (2×, HPS; left). Epidermis of the arm specimen C: important hemorrhage in the deep dermis and subcutaneous fat (1.25×, HPS; right).

Figure 22.27â•‡ The extravasated red blood cells dissect the fat conjunctival septa and the fat cells. Coalescence of the broken adipocytes (10×, HPS; left). Presence of extravasated RBCs between collagen fibers of the reticular dermis (20×, HPS; right).

Figure 22.28â•‡ Focal loss of the corneal layer on the surface of skin (40×, HPS; left). An indentation compression zone of skin (20×, HPS; right).

edematous epidermis with loss of the stratum corneum (FigureÂ€22.40, right). In the center of specimen B, there was a superficial surface erosion of the corneum layer and intercellular edema in the epidermis. As for specimen C, the epidermis was ulcerated; the ulceration extended into the superficial dermis with an overlying fibrinoleucocytic exudate (scab) (FigureÂ€22.41, left). In these three cutaneous specimens, one could observe an acute inflammatory reaction that was relatively important in the middle and deep dermis. The inflammatory cells were around the vessels and in the

interstitium. The inflammatory infiltrate was more discrete in the superficial dermis.

22.6â•…Conclusion Although the microscopic study of these bites enabled us to collect interesting histological data and to draw certain conclusions, it proved to be a very partial synopsis. How do we continue and refine this study, whose ultimate goal is to understand human bitemarks better? There is still much to do and the challenge is great.

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Figure 22.29 Multiple overlapping healed and fresh bitemarks on the right arm.

Figure 22.30 Bitemark on posterior left leg (upper left) and left arm (upper right) excised (lower left) and transilluminated (lower right).

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Figure 22.31 Excised multiple overlapping healed and fresh bitemarks on the right arm (upper left, lower left) and transilluminated bitemark from the left leg (right).

Figure 22.32 Specimen of the bite on the right hand (2×, HPS; left). Specimen B of the bite on the right hand (2×, HPS; right).

Figure 22.33 Hyperplastic and hyperkeratotic skin (10×, HPS; left). Zone of indentation covered with a regenerated epithelium (40×, HPS; right).

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Figure 22.34 Located near the central zone of indentation, the surface of the skin is covered with regenerated skin. The

blood vessels of the papillary dermis are dilated and congestive and there is extravasation of RBCs (20×, HPS; left). The conjunctival septa of the hypodermis are widened and fibrous. Presence of small clusters of spumous macrophages in the adipocytes (10×, HPS; right).

Figure 22.35 Hemorrhage in the major part of the cutaneous specimen with deposits of fibrin, granulation, and inflammatory cells both acute and chronic (10×, HPS; left). Presence of hemorrhage, fibrin, granulation tissue, and fibrinous thrombi in the subcutaneous fat (10×, HPS; right).

Figure 22.36 With enlargement, a small fibrinous thrombus is seen (40×, HPS; left). Specimen A of the bite site on the posterior surface of the left leg, where the presence of a subcorneal vacuole and a hemorrhage in subcutaneous fat can be seen (2×, HPS; right).

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Figure 22.37 Specimen B of the bite site on the posterior surface of the left leg. Light hemorrhage in the hypodermis in

comparison with specimen A (20×, HPS; left). Subcorneal vacuole with cellular remains intravesicular and necrosis of the skin of the floor of the vacuole (20×, HPS; right).

Figure 22.38 Small central necrosis of all the layers of the skin, isolated necrotic keratinocytes and extravasated RBCs in the papillary dermis (40×, HPS; left). Margination of the neutrophils in a blood vessel of the deep dermis (60×, HPS; right).

Figure 22.39 Perivascular and interstitial acute inflammatory infiltrate in the deep dermis (40×, HPS; left). Specimen B of the bite site on the left arm, at low power, showing a focal hemorrhage in the hypodermis (20×, HPS; right).

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Figure 22.40 Perivascular acute congestion in the hypodermis and infiltration of the wall of an artery by neutrophils (20×, HPS; left). Loss of the corneal layer, necrosis of all the thickness of skin, and intracellular edema of the adjacent keratinocytes (40×, HPS; right).

Figure 22.41 Scab covering the entire thickness of the skin (20×, HPS; left). Infiltrate of neutrophils between collagen fibers of dermis (40×, HPS; right).

Acknowledgments I wish to thank the following people: Serge Gauvin and Sylvie Auger, Laboratoire de Sciences Judiciaires et de Médecine Légale (LSJML) histology technicians, for the professionalism and excellence of their work and collaboration Dr. Robert Dorion, forensic odontologist at the LSJML, for the passion and enthusiasm he transmits to others for his work, the indispensible aid in the translation of this chapter, and the confidence and encouragement he instilled for this project and work in progress

Dr. Yasmine Ayroud for proofreading this chapter Dr. Marie-Josée Perron for her smile, her professionalism, and the confidence she imparted during the study Louise, Isabelle, Claude, Pauline, Albert, Gilles, Claudette, Carole, and Helene for their friendship and their unwavering support Above all, I want to dedicate this work and future research projects to “Zaza,” collaborator of the first order and ardent assistant pathologist with an exceptional talent, for whom courage and perseverance take on a special meaning.

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References 1. Meyer, W., R. Schwarz, and K. Neurand. 1978. The skin of domestic mammals as a model for the human skin, with special reference to the domestic pig. Current Problems in Dermatology 7:39–52. 2. Lavker, R. M., G. Dong, P. Zhen, and G. F. Murphy. 1991. Hairless micropig skin: A novel model for studies of cutaneous biology. American Journal of Pathology 138 (3): 687–697. 3. Sullivan, T. P., W. H. Eaglstein, S. C. Davis, and P. Mertz. 2001. The pig as a model for human wound healing. Wound Repair and Regeneration 9:66–76. 4. Vardaxis, N. J., T. A. Brans, M. E. Boon, R. W. Kreis, and L. M. Marres. 1997. Confocal laser scanning microscopy of porcine skin: Implications for human healing studies. Journal of Anatomy 190:601–611. 5. Marcarian, H. Q., and M. L. Calhoun. 1966. Microscopic anatomy of the integument of adult swine. American Journal of Veterinary Research 27 (118): 765.

6. Smith, J. L., and L. Calhoun. 1964. The microscopic anatomy of the integument of newborn swine. American Journal of Veterinary Research 25 (104): 165–173. 7. Montagna, W., and J. S. Yun. 1964. The skin of domestic pig. Journal of Investigative Dermatology 43:11–21. 8. Mowafy, M., and R. G. Cassens. 1975. Microscopic structure of pig skin. Journal of Animal Science 41 (5): 1281–1290. 9. Avon, S. L., J. T. Mayhall, and R. E. Wood. 2006. Clinical and histopathological examination of experimental bite marks in vivo. Journal of Forensic Odontostomatology 24:53–62. 10. Dorion, R. B. J., and M. J. Perron. Macroscopic and microscopic study of the effects of freezing and thawing on bite marks. Proceedings of the 62nd Annual Meeting of American Academy of Forensic Sciences, Seattle, WA, Feb. 25, 2010.

Genotypic Comparison of Bacterial DNA Recovered from Bitemarks and Teeth Geoffrey R. Tompkins

23

Contents 23.1 Introduction 23.2 Oral Microbiology 23.3 Pioneering Work 23.4 Recovery of Oral Streptococci from Bitemarks 23.5 Genotypic Identification of Oral Streptococci 23.6 Current and Future Research 23.7 Conclusions Acknowledgments References

453 454 454 455 455 459 459 459 459

23.1â•…Introduction Recent concerns over the scientific validity of entrenched forensic procedures, such as fingerprinting, have caused judicial systems worldwide to question the evaluation of evidence by expert witnesses [1]. The conventional morphometric analysis of bitemarks has received particular attention in this regard, in part because of the lack of statistical determination of the uniqueness of an individual’s dentition [2–4]. Despite increasingly sophisticated and rigorous methods of analysis, as highlighted in this volume, this fundamental issue and the informed yet necessarily subjective interpretation required in the analysis of many bitemarks will likely continue to cloud and even discourage morphometric analysis. A principal driver in the demand for rigorous scientific support for forensic analyses comes from the astonishing resolving power of deoxyribonucleic acid (DNA) analyses that have been introduced and accepted as evidence over the last couple of decades [1]. An individual’s unique genetic profile can now be determined from very small samples of blood, semen, hair, or epithelial cells, and such profiles, in conjunction with other biochemÂ�ical and immunological tests, have the statistical capability to distinguish all humans [5]. The National Academy of Sciences report [3] demands a reevaluation of current approaches to bitemark analysis, and developÂ� ment of robust techniques will more than likely focus on molecular methods for the present [1]. Whatever new technological developments are adopted by the forensic community, the continued involvement of the examining forensic odontologist is assured because his or her skills will be essential in identifying bitemarks and

obtaining appropriate samples to submit for DNA analysis by an approved laboratory. Despite significant advances in DNA technology, the recovery of the biter’s DNA from a bitemark inflicted on human skin (living or not) remains a difficulty because enzymes (nucleases) present in saliva rapidly degrade DNA [6]. The temperature of living skin undoubtedly promotes the activity of the nucleases; the half-life for DNA maintained at 37°C in saliva has been estimated at less than 1 minute [7]. Furthermore, some salivary components can interfere with the polymerase chain reaction (PCR), the central technique used to amplify DNA sequences from forensic samples [8]. These problems have been addressed and, to an extent, overcome by David Sweet and collaborators, who reasoned that the biter’s DNA will be protected from salivary nucleases by sequestration within oral epithelial cells deposited in the bitemark; they devised a method to lift intact oral cells gently from bitemarks for subsequent DNA analysis [6]. However, even under controlled experimental conditions, using human cadavers and drops of saliva, this DNA recovery method is not always successful [6]. Other researchers also report encouraging yet incomplete results in amplifying human DNA markers from saliva deposited experimentally on living human skin [9] and on inanimate surfaces [8]. Anecdotal reports suggest that the success rate for amplifying human DNA from saliva stains and bitemarks is lower in field situations. Owing to the difficulty of amplifying human DNA, this author has investigated the recovery and analysis of other potentially discriminative markers that may be deposited in bitemarks. Specifically, the feasibility of genotypically matching oral bacteria from the teeth of a

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suspected biter to those taken from a bitemark has been assessed. From the outset, though, it should be emphasized that this approach is not intended as an alternative to recovering the biter’s DNA, but rather as a contingency that may provide valuable evidence in situations where human DNA is not recovered. Every attempt should be made to recover human DNA derived from the biter because this provides the most compelling evidence to associate that individual to the recipient [10].

23.2 Oral Microbiology The human mouth contains a diversity of microbial habitats, and estimates indicate that as many as 500 distinct species of bacteria may inhabit the oral cavity [11]. Of these, the genus Streptococcus is the most prolific group [12]. Members of this genus not only are the most common bacteria on the surfaces of the teeth but also include the colonizing “pioneers” that attach to the tooth surface within minutes of removal by mechanical prophylactic procedures [12,13]. Thus, in the absence of aggressive antimicrobial treatment, the human teeth are inevitably coated with millions of bacteria, many of which belong to the genus Streptococcus. Most species of Streptococcus are largely benign (nonpathogenic) and live on various surfaces within the mouth, including the teeth and the oral soft tissues [14]. Streptococci are rarely cultured from healthy human skin. The more pathogenic species such as Streptococcus pyogenes (the causative agent of streptococcal pharyngitis, which is a prequel to rheumatic fever, scarlet fever, and other potentially fatal conditions) and Streptococcus pneumoniae (the most common etiologic agent of community-acquired pneumonia) have been intensively studied taxonomically. However, the more common oral species, with the possible exception of the group known as the mutans streptococci (implicated in the initiation of dental caries), are relatively poorly defined. The majority of benign supragingival plaque streptococci are often collectively referred to as the “mitis group” and include the species S. sanguinis, S. parasanguinis, S. mitis, S. oralis, S. gordonii, and S. crista [15]. Traditional taxonomic methods, such as the ability to ferment specific carbohydrates, offer poor discrimination between the oral streptococci, suggesting that the species’ distinctions may be ill founded [16]. However, attempts to resolve these issues by molecular methods have revealed tremendous genotypic diversity within the group. Thus, although they are physiologically and biochemically similar, the arrangement of their genetic material is quite heterogeneous. Taxonomic

comparisons by restriction fragment-length polymorphism (RFLP) analysis of whole genomic DNA and by arbitrarily primed polymerase chain reaction (AP-PCR) techniques have served only to emphasize the genotypic diversity [17–19]. For example, of a collection of 72 isolates compared by AP-PCR, none shared identical amplicon profiles [19]. An underlying reason for this diversity may stem from the widespread ability of these bacteria to exchange and rearrange genetic material by the process known as genetic transformation. Competence for transformation in the oral streptococci is chromosomally encoded [20] and occurs under experimental conditions designed to mimic the oral environment [7]. The ubiquity and number of streptococci colonizing the human teeth would seem to imply that such bacteria are deposited on every surface bitten by human teeth. In view of the extreme genotypic diversity displayed by these organisms, the question arises as to whether bacteria recovered from bitemarks inflicted on human skin can be genotypically matched, with any degree of specificity, to bacteria derived from the teeth responsible for the bite.

23.3 Pioneering Work Elliot and colleagues originally proposed the concept of recovering oral bacteria from bitemarks for forensic purposes [21]. In their studies, freshly collected human saliva was applied as droplets to living human skin, and the sites were sampled at intervals to determine the number of viable bacteria [21]. The study concentrated on isolating S. salivarius, which, although not strictly a tooth-colonizing organism, is probably the most abundant bacterium in the mouth [22] and likely to be deposited in most bitemarks. The experiment involved the selective and differential bacteriological culture medium Mitis-Salivarius agar [23] to isolate and culture viable streptococci from the skin surface. The study found that S. salivarius is cultivable for at least 3 hours following deposition of the saliva but that bacterial viability decreases rapidly over this period [21]. The experiment was not extended beyond 7 hours. A subsequent publication reported the application of a mass spectrometric method to distinguished strains of S. salivarius [24]. Thus, although not a genotypic approach, the essential principle of recovering and distinguishing (at the subspecies level) oral bacteria derived from the biter was investigated. Unfortunately, the research program seems to have ended before determination of the statistical resolution of S. salivarius strain distinction by

Genotypic Comparison of Bacterial DNA Recovered from Bitemarks and Teeth

this method; to this author’s knowledge, there have been no reports of field application.

23.4â•…Recovery of Oral Streptococci from Bitemarks Over a decade later, our group initiated studies using a similar approach but elected to focus on the streptococci associated with the tooth surface, rather than S. salivarius [25]. There were two reasons for this choice. First, essentially every healthy human being harbors large numbers of these organisms on the teeth, and therefore it may be anticipated that significant numbers of such bacteria are likely to be deposited in a bitemark. Second, several studies [17–19] report the extreme genotypic diversity of the (non-salivarius) oral streptococci (there is little such information on S. salivarius). In our studies [25,28], it was essential to deposit the bacteria in the most authentic way possible, and thus the experiments involved participants biting themselves as firmly as they could on the upper arm. It is surprising how hard an individual can bite himself or herself, and many of the self-inflicted bites produced marked contusions with subsequent bruising (FigureÂ€23.1). Our studies also used Mitis-Salivarius agar to cultivate viable streptococci. Sampling concentrated on the imprints of the mandibular incisors and canines because these teeth generate the principal force in biting, and therefore the shearing interaction between skin and tooth is likely to be the greatest and should result in deposition of larger numbers of bacteria. The experiment was protracted such that bitemarks were sampled for up to 24 hours following the bite. The finding reiterated those of the earlier study [21] by demonstrating that the numbers of recoverable bacteria decreased exponentially following deposition on the skin surface [25].

455

Nevertheless, thousands of bacteria were recoverable after a 24-hour interval, provided the bitemark remained relatively undisturbed, whereas only one or two colonies (at most) were ever recovered from unbitten (control) upper-arm sites [25]. Female assault victims, on average, seek medical attention within 11 hours of an attack [26], and thus there should be opportunity to recover viable oral bacteria derived from the biter in many instances where biting occurs. Extrapolation of the data suggests that viable bacteria would not be recoverable from living skin beyond 30 hours, but we have not yet studied survival of streptococci on nonliving skin. Under authentic circumstances, however, a number of factors could conceivably reduce either the viability or recoverability of deposited bacteria. For example, a physical struggle could generate heat and perhaps sweat at the skin surface. Thus, the effect of 10 minutes of moderate exercise (running on a treadmill) was assessed immediately before biting and demonstrated that, indeed, this led to decreased bacterial recoverability [25]. Furthermore, prior application of moisturizing lotion (containing preservatives), manual rubbing immediately after biting, and (not surprisingly) washing with soap all reduced bacterial recoverability [25]. However, with the exception of washing with soap, informative numbers of bacteria could be recovered from all experimental subjects. Bacteria could also be recovered from a variety of tested fabric types through which bites were inflicted [25]. Note that a recent study that sought to catalogue the microbiome of human skin by PCR amplification of microbial ribosomal DNA sequences from six volunteers revealed that Streptococcus mitis (generally regarded as an oral species) may compose 5–10% of bacteria on the skin of humans [27]. However, in sampling unbitten skin sites, it is rare to cultivate more than one or two streptococcus colonies [25], suggesting that streptococcal DNA amplified from human skin derives largely from nonviable cells.

23.5â•…Genotypic Identification of Oral Streptococci

Figure 23.1â•‡ Self-inflicted (experimental) bitemark on the upper arm after 3 hours.

Having established that oral bacteria survive in bitemarks long enough for many practical forensic purposes, the next phase of the study aimed to determine whether recovered bacteria could be genotypically matched to those isolated from the teeth responsible for the bite and to get an indication of the exclusivity of streptococcal strains isolated from different individuals. Genotypic comparison of bacterial strains was initially accomplished by RFLP analysis of whole genomic

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DNA (genotypic “fingerprinting”) [25]. Although this is more labor intensive than PCR-based approaches, it offers potentially greater resolution. By comparing 10 bacterial isolates from the teeth with 10 from the self-inflicted bitemarks of eight subjects, the study demonstrated that at least one strain (usually more) could be matched between the two sites [25]. Specific bacterial genotypes were unique to each individual within the study [25]. In other words, there was no evidence of bacterial strain sharing between unrelated participants (53 genotypes isolated in total). It was anticipated that one or two strains would dominate the teeth of an individual, but the results suggested that there are likely to be several frequently isolatable strains [25]. In addition, the study indicated that the skin exerts a selective pressure on the deposited bacteria. Thus, the bacterial strains surviving for protracted periods on the skin were not necessarily the most dominant strains on the tooth surface. Subsequent investigations required examination of a greater number of isolates. As a result, an AP-PCR method was adopted that allowed more rapid identification of larger numbers of bacteria. The AP-PCR assessment was structured as a simulated crime situation in which an investigator compiled a genomic database of bacteria isolated from the teeth of eight participants [28]. He was then given two Mitis-Salivarius agar plates bearing bacterial colonies cultured from swabbed samples from self-inflicted bitemarks, purportedly from two of the eight individuals, and attempted to identify the biters. In the course of this study, 50 streptococcal isolates from the teeth of each participant and from each of the two bitemarks were genotypically typed. Examples of PCR amplicon profiles comparing bacteria isolated from teeth and bitemarks are shown in FigureÂ€23.2. Analyses of the dental isolates indicated that in most individuals one or two genotypes compose around 60% of isolates, but that there may be as many as 23 strains harbored by an individual [28]. The study also supported the previous observation that strains predominating on the tooth surface were not always the prevalent strains recovered from the bitemarks. A total of 105 genotypes were isolated from the eight individuals; again, none of the bacterial genotypes were shared between individuals [28]. The investigator was confidently and correctly able to identify one of the biters by comparing the bacterial genotypes from the bitemark to those in the database (FigureÂ€ 23.2). However, despite repeated attempts, the origin of the second bitemark could not be determined. In fact, the second sample did not derive from one of the participants from the original database (i.e., it was included as a negative control).

One year later, the teeth of the same eight individuals were again sampled, and AP-PCR analyses indicated that identifiable bacterial genotypes had been retained by each of the participants [28]. This strain stability implies a reasonable likelihood that bacteria recovered from an authentic bitemark associated with criminal activity may be matched to the biter some months (and possibly years) following an attack. The effects of oral pathologies and of antibiotic and antiseptic treatments on streptococcal genotypes have yet to be investigated. Deriving from the idea that oral bacteria are inevitably associated with saliva, two recent studies report the value in amplifying oral bacterial DNA from forensic material to determine its origin. Nakanishi et al. determined that S. salivarius DNA is a more reliable marker for saliva than is S. mutans because the former was amplified from all saliva stain samples tested and the latter only from 60% [29]. By this method, neither organism was amplified from various other body fluids or from skin swabs; therefore, S. salivarius DNA can be considered an accurate and sensitive marker for saliva [29]. More recently, using multiplex PCR with primers designed to three common oral bacterial species, Power et al. were able to detect DNA in bloodstains contaminated with as little as 0.01 µL of saliva, providing a sensitive method for identifying expirated blood [30]. An important element of the current research is to ensure that it is ultimately accessible to forensic investigators. One potential obstacle to cultivation of oral bacteria from an authentic bitemark might be the unavailability of the selective culture medium, which is generally prepared at least a day before use. If there is no stock of Mitis-Salivarius agar plates, then the attending examiner cannot expect to recover viable bacteria within the time frame required. Since recovery and amplification of human DNA must always be given priority, analysis of bacterial DNA will inevitably be a secondary consideration. It is unlikely that forensic examiners will consider apportioning even a small and potentially valuable saliva sample to cultivate oral bacteria even if the necessary selective agar is available. Nevertheless, the examiners will have swabbed the bitemark to recover oral epithelial cells, and this sample will contain bacteria that could be exploited if amplification of human DNA markers is unsuccessful. A further perceived advantage in amplifying streptococcal DNA directly from the bitemark follows from the demonstration that oral bacteria can be cultivated from bitemarks for no more than 24 hours following biting [25]. The bacteria will die (becoming uncultivable); however, because streptococci are gram-positive and relatively resilient to lysis, nonviable bacteria (contain-

Genotypic Comparison of Bacterial DNA Recovered from Bitemarks and Teeth

457

Kb 12.2

Kb 12.2

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12.2

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Figure 23.2â•‡ Comparison of arbitrarily primed PCR amplicon profiles of streptococci isolated from an experimental bitemark with those from the teeth of three participants. Each lane resolves the amplicons generated by one bacterial colony. The extreme lanes on each gel contain molecular size standards. Note the similarity in profiles between the bitemark and participant 4, who was responsible for the bitemark. (Rahimi, M. et al. 2005. Journal of Applied Microbiology 99:1265–1270. Reproduced with permission.)

ing DNA) should persist in the bitemark considerably longer than 24 hours following biting, if the bitemark remains relatively undisturbed. This has implications for the forensic examination of a deceased victim discovered several days following a crime; if there is a bitemark, then there should be associated streptococcal DNA derived from the biter. Recent investigations have therefore focused on direct amplification of streptococcal DNA from bitemarks (i.e., without the need to culture the bacteria first). The approach involved resolution of PCR-generated amplicons by denaturing gradient gel electrophoresis (PCR-DGGE) according to their melting characteristics, following the method of Rudney, Pan, and Chen [31]. Using the previously described streptococcus-specific primers [31], streptococcal amplicons generated from self-inflicted bitemarks were compared with those from teeth [32]. Amplification was successful from 19 of 24

self-inflicted bitemarks and from 24 sampled lower incisor arches [32]. The number of bitemark amplicons was always less than those from the corresponding teeth, except in one case in which there were equal numbers of perfectly matching amplicons. When the amplicon profiles from all bitemarks and teeth were compared (excluding profiles with less than six amplicons), the mean proportion of amplicons from bitemarks that matched those from the teeth responsible for the bite was 82.8%; the average match between bitemarks and teeth that did not cause the bitemark was significantly less at 36.2% [32]. The 16S rDNA locus is relatively conserved throughout the genus, so there is good reason to expect that targeting multiple and more variable loci will provide highly individualized amplicon profiles from bitemarks that can be matched with a high degree of confidence to the teeth responsible. Examples of PCR-DGGE profiles are shown in FigureÂ€23.4.

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M

B

T

B

T

B

T

B

T

M

Kb 12.2 4.0 2.0 1.0 0.5

Figure 23.3â•‡ Direct comparison of AP-PCR products derived from four Streptococcus colonies isolated from a self-

inflicted bitemark (B) with four from the lower incisors of the biter (T). Calibration markers (M) are in the extreme lanes.

M

S1

B1

T1

S2

B2

T2

S3

B3

T3

Figure 23.4â•‡ PCR-DGGE comparison of streptococcal amplicons generated from unbitten skin site (S), bitemark (B), and lower incisors (T) from each of three participants (indicated by subscripted number). Lane M contains amplicons generated from a selection of oral streptococcus species constituting standards to facilitate intergel comparisons.

Genotypic Comparison of Bacterial DNA Recovered from Bitemarks and Teeth

23.6 Current and Future Research An important affirmation from our PCR-DGGE study was that streptococcal DNA may be amplified directly from bitemarks [32]. Originally, it was intended to increase the resolution of the PCR-DGGE approach using multiple loci. However, with recent dramatic improvements in DNA sequencing technology, the focus has been switched to the applicability of high-throughput DNA sequencing [33] in order to characterize and compare streptococcal DNA. Initial attempts using four loci (including the 16S rDNA used in the PCR-DGGE) have yielded approximately 10,000 sequence reads from each of 20 saliva samples with as many as 15 distinct sequences (i.e., bacterial strains) per locus (unpublished). Our current challenge is to adapt available sequencing software to manage and analyze the large amount of data generated and, in particular, to determine the statistical probability of two individuals sharing common streptococcal sequences.

23.7 Conclusions These studies have established that streptococci deposited in bitemarks inflicted on living human skin by human teeth exhibit sufficient genotypic diversity to suggest that each human harbors a distinct dental microbiota that could be exploited in the analysis of bitemarks. Bacteria and bacterial DNA recovered from bitemarks can be genotypically compared with isolates from the teeth of suspects, with a high degree of confidence that matches will be made to isolates from the biter. The long-term stability of bacterial strains harbored by an individual indicates that the biter, even if apprehended months later, is likely to retain many of the same bacterial genotypes on his or her teeth. Although this researcher has been consulted by forensic laboratories, the application of the techniques described by Borgula et al. [25], Rahimi et al. [28], and Hsu et al. [32] or others [24] to the investigations of crimes involving bitemarks has, as of this writing, not been used. Certainly this is ongoing research, and the development of techniques that are not only accessible to the examining forensic odontologist but also comprehensible to jurors is part of the research challenge.

Acknowledgments The support of the New Zealand Dental Research Founda tion, the New Zealand Lottery Board, and the Maurice

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and Phyllis Paykel Trust is gratefully acknowledged. Permission to reprint the photograph in Figure 23.2 was obtained from John Wiley & Sons.

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15. Rudney, J. D., and C. J. Larson. 1999. Identification of oral mitis group streptococci by arbitrarily primed polymerase chain reaction. Oral Microbiology and Immunology 14:33–42. 16. Truong, T. L., C. Menard, C. Mouton, and L. Trahan. 2000. Identification of mutans and other oral streptococci by random amplified polymorphic DNA analysis. Journal of Medical Microbiology 49:63–71. 17. Rudney, J. D., E. K. Neuvar, and A. H. Soberay. 1992. Restriction endonuclease-fragment polymorphisms of oral viridans streptococci, compared by conventional and field-inversion gel electrophoresis. Journal of Dental Research 71:1182–1188. 18. Alam, S., S. R. Brailsford, R. A. Whiley, and D. Beighton. 1999. PCR-based methods for genotyping viridans group streptococci. Journal of Clinical Microbiology 37:2772–2776. 19. Wisplinghoff, H., R. R. Reinert, O. Cornely, and H. Seifert. 1999. Molecular relationships and antimicrobial susceptibilities of viridans group streptococci isolated from blood of neutropenic cancer patients. Journal of Clinical Microbiology 37:1876–1880. 20. Jenkinson, H. F. 2000. Genetics of Streptococcus sanguis. Washington, D.C.: American Society for Microbiology. 21. Brown, K. A., T. R. Elliot, A. H. Rogers, and J. C. Thonard. 1984. The survival of oral streptococci on human skin and its implication in bite-mark investigation. Forensic Science International 26:193–197. 22. Gibbons, R. J., B. Kapsimalis, and S. S. Socransky. 1964. The source of salivary bacteria. Archives of Oral Biology 9:101–103. 23. Chapman, G. H. 1944. The isolation of oral streptococci from mixed cultures. Journal of Bacteriology 48:113–114. 24. Elliot, T. R., A. H. Rogers, J. R. Haverkamp, and D. Groothuis. 1984. Analytical pyrolysis of Streptococcus salivarius as an aid to identification in bite-mark investigation. Forensic Science International 26:131–137.

25. Borgula, L. M., F. G. Robinson, M. Rahimi, K. Chew, K. R. Birchmeier, S. G. Owens, J. A. Kieser, and G. R. Tompkins. 2003. Isolation and genotypic comparison of oral bacteria from experimental bite marks. Journal of Forensic Odontostomatology 21:23–30. 26. Peipert, J. F., and L. R. Domagalski. 1994. Epidemiology of adolescent sexual assault. Obstetrics & Gynecology 84:867–871. 27. Gao, Z., C. H. Tseng, Z. Pei, and M. J. Blaser. 2007. Molecular analysis of human forearm superficial skin bacterial biota. Proceedings of National Academy of Sciences USA 104:2927–2932. 28. Rahimi, M., N. C. K. Heng, J. A. Kiesser, and G. R. Tompkins. 2005. Genotypic comparison of bacteria recovered from human bite marks and teeth using arbitrarily primed PCR. Journal of Applied Microbiology 99:1265–1270. 29. Nakanishi, H., A. Kido, T. Ohmori, A. Takada, M. Hara, N. Adachi, and K. Saito. 2009. A novel method for the identification of saliva by detecting oral streptococci using PCR. Forensic Science International 183:20–23. 30. Power, D. A., S. J. Cordiner, J. A. Kieser, G.R. Tompkins and J. Horswell. 2009. PCR-based detection of salivary bacteria as a marker of expirated blood. Science & Justice doi:10.1016/j.scijus.2009.04.006. 31. Rudney, J. D., Y. Pan, and R. Chen. 2003. Streptococcal diversity in oral biofilms with respect to salivary function. Archives of Oral Biology 48:475–493. 32. Hsu, L., D. A. Power, J. P. Burton, J. H. Hauman, J. R. Tagg, and G. R. Tompkins. 2007. Comparison of streptococcal DNA amplified from human bite marks and teeth by denaturing gradient gel electrophoresis. New Zealand Medical Journal 120:2–3. 33. Nasidze, I., D. Quinque, J. Li, M. Li, K. Tang, and M. Stoneking. 2009. Comparative analysis of human saliva microbiome diversity by barcoded pyrosequencing and cloning approaches. Annals of Biochemistry 391:64–68.

Collection of Evidence from the Suspect

VII

24

The Suspect L. Thomas Johnson Contents 24.1 Court Order/Informed Consent 24.2 Dental History 24.3 Standard/Digital Photography 24.4 Extraoral Examination 24.5 Intraoral Examination 24.6 Impressions 24.7 Study Casts References

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24.1â•…Court Order/Informed Consent In 1984 the American Board of Forensic Odontology (ABFO) established guidelines covering the subject of bitemark analysis. It has subsequently updated these guidelines from time to time to include the collection of evidence from the suspect. The guidelines are available on the ABFO’s Web site (www.abfo.org) and are outlined in Appendix 1 of this edition. Before collecting evidence from a suspect, the requesting agency should obtain a search warrant, court order, or informed consent. The forensic odontologist should discuss with appropriate authorities and list all procedures required under the warrant for the collection of evidence from a suspect, prior to submission to a court for approval. Once the request is approved, the odontologist should retain a copy of the search warrant. The document should be read carefully before proceeding, to assure that it clearly specifies the requested collection of evidence. This is an essential component to admissibility of the evidence in court. Motions filed by opposing counsel may later challenge any warrant shortcomings or the collection of unspecified material. In most jurisdictions, the warrant applicant (officer or detective) is present for its execution. In practice, it is also advisable to have the law enforcement case investigator present even when informed consent has been obtained. It is also good practice to have the session video recorded to demonstrate exactly what was done and when, who was present, and the demeanor of all parties present. As a precautionary measÂ�ure, the odontologist should monitor his or her actions with a checklist. This serves at least two purposes: It assures that the mandated procedures are followed—and no more, and it provides a detailed recording of a myriad of other information.

Details such as the date, time, location, and names and titles of those present, affected, witnessing, and assisting in the procedure should always be documented. All of these details will ultimately serve in report writing and as a refresher for court testimony.

24.2â•…Dental History The suspect’s complete dental history, including recent dental treatment, periodontal disease, and other pathology, should be documented. The maximum extent of jaw opening, the degree of lateral excursions, and the ability to protrude the mandible may be crucial to the analysis. Mobility and missing, supernumerary, or damaged teeth should be charted. The subject’s present and past dental records should be subpoenaed to establish the dental condition at the time of bitemark infliction. This is particularly important if there has been an extended period of time from infliction of the bite to examination of the suspect. Additional photographic (smiling photographs) and radiographic (medical, orthodontic, etc.) records and casts might be important for this purpose. Consult the checklist in Appendix 2.

24.3â•…Standard/Digital Photography A protocol should be established before beginning dental and suspect photographs. Conducting the photographic documentation in the same orderly fashion each time avoids unintentional omissions and reduces the time allotment. It is desirable for the odontologist to have an assistant when executing the collection of evidence. Since the odontologist will be wearing personal protective gear, it

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would otherwise be necessary to remove the gloves to avoid contamination of the camera and accessory equipment. Having a competent assistant or, even better, a professional photographer set up the camera alleviates this problem. The odontologist should guide the placement of the camera, determining the views required. Since there will generally be only one opportunity to document the subject, it is advisable to bracket each exposure [1,4,5]. This author suggests using a 35-mm single-lens reflex camera with normal and macrolenses with full manual capability as the ideal photographic armamentarium for the collection of evidence from a suspect. An alternative zoom lens is suggested with focal length from medium-wide angle (28–35 mm) to medium telephoto (70–135 mm) [1]. Close-up capability with a minimum of 1:4 magnifications is advantageous [1]. Zoom lens or a noncalibrated system poses a problem for 1:1 intraoral photographs of occlusal surfaces. A camera with interchangeable lenses is most desirable. A ring light, detachable hot shoe flash, PC connector, cheek retractors, and a quality front surface intraoral mirror are advantageous. A medium-format camera for extraoral photographs is also desirable. Even more desirable is a large-format camera capable of 1:1 images. The author utilizes a Polaroid CU-5 scientific camera with the dental accessory kit for 1:1 and 2:1 images. This camera is capable of accepting either a Polaroid model 545i, 4 × 5-inch film holder with Polacolor ER, type 59 professional 4 × 5-inch sheet film or a 4 × 5-inch negative film holder with KodakPorta NC (100 ISO). There are two advantages in using this camera: The Polaroid exposures serve as test images and also provide 1:1 instant working photographs. The exposure values for the negative film are very similar. Since the camera produces 4 × 5-inch prints with the intraoral kit, captured images are approximately 1:1, making enlargements unnecessary.

However, with the availability of instant sheet film in the 4 × 5-inch format becoming a problem, being able to view immediate test images may no longer be possible. The CU-5 large-format scientific camera with its 1:1 dental intraoral accessories is still preferred, as long as negative print film remains available. Begin with fullface, midrange photographs for identification of the suspect. To avoid distortion, if a medium-format camera is unavailable, use a long lens. Remember that identification of the subject of a workup at trial might be delayed for months or, in unusual cases, years. Some photographers also expose right and left lateral subject profiles. Autofocus cameras must allow for full manual override or at least offer aperture and shutter priority. Using cheek retractors, close-up photographs of the dentition should be made with the teeth in occlusion (FigureÂ€ 24.1, left) and also at maximum opening (FigureÂ€24.1, middle). Photographing the biting surfaces of the teeth requires specialized equipment. An intraoral, front surface mirror and ring light are recommended for documenting the incisal and occlusal surfaces (FigureÂ€ 24.1, right). The CU-5 scientific camera with a 4 × 5-inch negative film holder with KodakPorta NC (100 ISO) and 1:1 dental kit enables the exposure of life-size images. Be aware, though, that images of the tooth surfaces taken with an intraoral mirror must be reversed when printed or visualized for comparison purposes. To avoid fogging of the mirror, request the subject to hold his or her breath momentarily while the mirror is inserted into the mouth and the exposure made. Increasingly, digital photography is replacing standard photography (see Chapters 7 and 8). There are some advantages to digital photography; however, expensive, high-end, megapixel equipment is necessary to create high-quality enlargements. Consider also that full manual capability is required for the desired goal. The effects of long-term storage of digital images have yet to be demonstrated, whereas negatives can be archived

Figure 24.1â•‡ Frontal view of the dentition in occlusion (left). A record of the subject’s maximum opening diameter. Note use of self-retaining cheek retractor (center) and the presence of a rotated, supernumerary incisor in the midline (right). Intraoral photographs taken with a mirror require reversal for bitemark comparison.

The Suspect

indefinitely. Digital files are also subject to accidental deletion or corruption. The FBI’s Scientific Working Group on Imaging Technologies (SWGIT) states that digital imaging processing is an accepted practice in forensic science (see Chapter 9). However, to be acceptable, any changes made to an image must meet the following criteria: The original image is preserved. The processing steps are logged. The end result is presented as a processed image that may be reproduced by applying the logged procedures. The recommendations of the SWGIT guidelines are followed [2]. In practice, the original images are placed in a separate directory called primary images, and the properties are changed to read-only, making it more difficult to overwrite them (D. E. Cadle, personal communication, 2009). Consequently, if the odontologist uses digital photography, the original digital image file must be maintained, and only copies should be used to make adjustments. By maintaining a log of the adjustments made to the copies and the computer program used to view and adjust them, the processes used and results obtained are reproducible. The more recent versions of Adobe® Photoshop® can be programmed to record all changes automatically. Interestingly, for viewing raw and processed images, the courts have yet to require supplying the appropriate software to opposing counsel.

24.4â•…Extraoral Examination The examiner should observe and record any significant factors that could influence the subject’s ability to bite (e.g., facial asymmetry, the classification of occlusion, any deviations of the jaws in opening and also in lateral excursions) [3]. Complaints of joint clicking or joint pain should be evaluated and recorded. Record the presence of facial hair (e.g., moustache or beard). This also is a time to record the subject’s demeanor and any other information that may be pertinent.

24.5â•…Intraoral Examination Approach the intraoral examination as you would a complete oral/dental workup for any new patient. When possible, an assistant can chart the findings as dictated. This avoids chart contamination and saves time. The

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examiner should record all virgin, unerupted, missing, decayed, and restored teeth; prosthetic replacements; periodontal health; mobility; and overall oral health. A graphic representation of existing restorations and other dental conditions should be placed on an odontogram. The subject’s tongue size and functionality should be recorded, (e.g., ankyloglossia) [3]. Buccal swabs should be taken if enumerated in the search warrant or court order. Depending on the laboratory preference, swabs might need premoistening with sterile distilled water or saline solution. Be aware of the laboratory preference. The laboratory might require air-drying the swabs before packaging and returning them to the DNA unit. It is important to avoid crossÂ�contaminating the swabs with other DNA.

24.6â•…Impressions Full-arch dental impressions should be made with an American Dental Association (ADA)-accepted dental impression material, following the manufacturer’s directions. An elastomeric, accurate, and stable material (e.g., vinyl polysiloxane) is recommended. If it is at all possible, depending on the warrant mandate, a second set of impressions might prove beneficial. Record the type, manufacturer, and expiration date of the material used. Consult the Appendix 2 checklist. Water-based impression materials such as alginates are not recommended since they are not dimensionally stable, must be poured immediately, and the impressions cannot be preserved undistorted. The impression trays and/or the containers in which they are held should be immediately marked with case number, date, and personal identifiers such as initials. Along with the full-arch dental impressions, sample bites can be taken in an appropriate material to record the subject’s bite pattern. This author uses a horseshoeshaped wax wafer, called CoprWax, manufactured by the Surgident Corporation (FigureÂ€ 24.2, left). This is a valuable three-dimensional adjunct to dental casts and two-dimensional photographs. By using at least three separate registrations at progressive depths, a threedimensional representation of the dental characteristics is produced. The variation in patterns resulting from differences in incisal heights that can be seen in the bitemark is then more readily apparent.

24.7â•…Study Casts Casts should be poured in an ADA-approved dental material such as type II dental stone (FigureÂ€24.2, right) and

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Figure 24.2â•‡ Example of three-dimensional depth of closure into a softened wax wafer (left). Dental casts poured in type II beige dental die stone (right).

prepared in accordance with the manufacturer’s instructions. Common dental plaster and white die stone are not recommended; the latter is difficult to photograph and the former is too weak. Teeth or adjacent soft tissue on casts should not be altered, trimmed, or marked [3]. Casts should be identified at their base by case number and other personal identifiers. Models should be stored in identified boxes or containers as orthodontic casts would be in the dental office. Additional working duplicates of the master cast may be made using accepted duplication procedures and should be marked as duplicates. Warrant or court-ordered collected specimens, whether biologic, photographic, impressionistic, poured, or duplicated, may be considered evidence. Some jurisdictions consider only the photographic negatives and impressions as evidence. The photographic prints and poured models in those instances are considered work product. It is vital that the odontologist become thoroughly familiar with the legal concept of evidence in the jurisdiction in which he or she is working and the necessity for maintaining a chain of custody or possession. The integrity of evidence must be protected

from damage, alteration, and loss. It must be stored in a secure area and be accessible only to those entitled to use or view it.

References 1. Groffy, R. L. 1998. Criminal investigation photography. Unpublished monograph, Wisconsin Department of Justice, Crime Laboratory Bureau, 1–2. 2. Recommendations and guidelines for the use of digital imaging processing in the criminal justice system. Proceedings of the Scientific Working Group on Imaging Technologies (SWGIT), Ver. 1.2, June 2002 (http://www. fbi.gov/hq/lab/fsc/backissu/jan2000/swigit.htm). 3. American Board of Forensic Odontology. ABFO bitemark analysis guidelines, Diplomate reference manual (www.abfo.org). 4. Groffy, R. L. et al. 2008. Recognition, preservation and collection of bite mark evidence. Wisconsin 6. DepartÂ� ment of Justice, Crime Laboratory Bureaus. 5. Physical evidence handbook, 8th ed. 2009. Chapter 2, PhoÂ� tography. Wisconsin Department of Justice (http://www. doj.state.wi.us/dles/crimelabs/physicalEvidenceHB/).

Methods of Comparison

VIII

25

Methods of Comparison Jon Curtis Dailey Contents 25.1 Introduction 25.2 Test Bites 25.2.1 Static Test Bites 25.2.2 Wax 25.2.3 Styrofoam 25.2.4 Dental Impression Materials 25.2.5 Identical Substances 25.2.6 Animal Skin 25.2.7 Human Cadaver Skin 25.2.8 Dynamic Test Bites on a Volunteer 25.3 Direct Comparison 25.3.1 Suspect Biter and the Excised Tissue 25.3.2 Suspect Biter and the Bitemark Impression 25.4 Dental Nomenclature 25.5 Inverting Cast (Flip Horizontal) for Comparison 25.6 Overlays 25.6.1 Simple Overlays 25.6.2 Computer-Generated Overlays 25.7 Metric Analysis 25.8 Digital Analysis 25.9 Other Comparison Techniques 25.9.1 Pattern Analysis in Three Dimensions 25.9.2 Videotape 25.9.3 Ink Immersion Technique 25.9.4 The Dental Line-Up 25.9.5 Other Methods of Computer-Aided Visualization 25.10 Pattern Recognition Ability 25.11 Conclusion References

25.1â•…Introduction When authorities have identified the potential biter, his or her dental records provide the basis for comparison with the bitemark. The results of this comparison culminate with the forensic dentist’s opinion on the correlation between the suspected biter and the patterned injury. It must be noted that, from a historical perspective, the terminology used by forensic dentists for linking a suspected biter to the patterned injury has changed with time. This evolution has occurred to minimize ambiguity and to strengthen opinions related to bitemark casework as recommended by the

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National Academy of Sciences (NAS) report [1]. It is safe to conclude that such terminology will continue to evolve. Ideally, the biter’s dental casts would be directly apposed to the tooth-created indentations in the patterned injury on the skin. This is an extremely rare occurrence because the elastic rebound of skin renders tooth indentations fleeting. When present, they should be recorded and preserved and an accurate impression material should reproduce the three-dimensional replica of the bitemark. A more likely scenario for apposition exists with bitemarks in foodstuffs or other inanimate objects. FigureÂ€25.1 reveals a bitemark left in a piece of cheese.

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 25.2 A clear acrylic resin study model on a

bitemark photograph (note: no. 23 universal system of nomenclature).

Figure 25.1 Bitemark in cheese exhibiting maxillary (a) and mandibular (b) teeth imprints.

Unfortunately, in a large number of bitemark cases, the only evidence collected is photographs—a twodimensional representation of a three-dimensional object. The photographic evidence is currently compared to a two-dimensional overlay of the suspect’s teeth. Alternatively, transparent acetate overlays, photocopies, and other forms of recording tooth edges are employed. The three-dimensional version may be used to produce sample bites on a volunteer’s skin or on various materials serving as tissue substitutes. For clarity, this edition refers to two types of overlays: bitemark and dental. Each represents a transparent view of the bitemark or the suspect dentition.

25.2 Test Bites Test bites or sample bites are produced on various materials. The goal is to visualize the pattern produced by the biting edges of teeth in a position that simulates the bitemark injury. While apposition of the dental model to the bitemark itself might seem more logical, the process often obstructs the examiner’s view and, if applied directly to skin or the object that contains the bitemark, could modify it, especially if it were not the correct dentition. The issue has been addressed in part by the fabrication of clear dental models made of urethane dimethacrylate (Triad Clear Colorless Gel from Dentsply International, York, Pennsylvania), crystalclear epoxy resin (Marglass 658 from Acme Chemicals and Insulation Co., New Haven, Connecticut), and acrylic resin (Leocryl from Leone Orthodontics, Beaconsfield, New South Wales, Australia) [2,3]. The author considers Triad insufficiently transparent and recommends other

materials [2]. Figure 25.2 depicts a nonaltering/destructive method of apposing a clear dental model to a bitemark photograph. 25.2.1 Static Test Bites Static test bites represent a recording of the biting edges of the maxillary or mandibular teeth at one depth, at one moment in time, and without recording movement of the edges in the bitten substrate. 25.2.2 Wax Numerous types of waxes have been used over the years. Currently, Aluwax (Aluwax Dental Products Company, Grand Rapids, Michigan) remains very popular owing to its physical properties. This material is sold as U-shaped wafers in which a cloth base is sandwiched between layers of wax. The material is semirigid at room temperature, but can be softened in a variety of ways. Aluwax wafers were used to record the test bites in Figure 25.3. The quandary with wax lies in the question of how far the examiner should push the tooth edges into the wax. If teeth differ in horizontal plane or are otherwise malpositioned, how much should the wax be forced to bend before the teeth register? Does this introduce significant distortion, discrepant from the bitemark pattern? Figure 25.4 depicts wax bending. 25.2.3 Styrofoam Numerous illustrations from published literature demonstrate the limitations of test bites made into Styrofoam [4]. In 1984, the American Board of Forensic Odontology (ABFO) published the Bitemark Analysis Guidelines, which recommend the use of American Dental Associa tion (ADA)-approved materials for impression making

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#10

#10

#10

a #23

b #23

c #23

Figure 25.3â•‡ Static test bites in Aluwax (a). The suspect’s dental models (b) have been flipped horizontally to align with the pattern they would create. The Aluwax image has been digitized and “inverted” using Photoshop (c).

a b

Figure 25.4â•‡ Wax distortion created when the misaligned mandibular tooth was brought in contact with the wax.

and for the fabrication of dental models [5]. In 1994, the ABFO surveyed diplomates for the analytical methods used in comparison of bitemark evidence. The results were published as findings rather than as recommendations [6]. Styrofoam was one material in the analytical armamentarium of the time. Since accuracy in reproduction is an objective, the use of this material should be restricted to recording the biting edges of teeth for screening purposes only. It is not an ADA-approved dental material and does not meet the quality standards set forth by the ABFO standards for bitemark analytical methods [7]. 25.2.4â•…Dental Impression Materials When the bitemark involves inanimate objects, test bites can be created in similar objects for comparison. The goal is to reproduce dental details in the original

Figure 25.5â•‡ A bitten bolus of setting PVS impression material showing compressive distortion (a) and stretching distortion (b).

bite, using the suspected biter’s dental models. The use of a bolus of previously set impression material has been advocated [8]. This is not applicable following the final set of a rigid impression material such as polyvinylsiloxane (PVS) or polyether, which sets with an enormous biting resistance. An alginate impression material (irreversible hydrocolloid) would be the material of choice in such a situation. FigureÂ€25.5 demonstrates a bite into a bolus of PVS prior to the final set of the material, resulting in poorly recorded tooth edges.

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1 mm

mm 1

22

23 24 25

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on the living animal and removing it later. Therefore, these test bites differ little from the other forms of static test bites. Avon [20] and Dorion [21–25] (and elsewhere in this edition) have created antemortem and postmortem bites on pigskin. 25.2.7â•…Human Cadaver Skin

Cut 1 Cut 2

Recent human cadaver skin studies [26–28] (also discussed elsewhere in this edition) have served to increase our understanding of the dynamics and distortion properties of human skin greatly.

#1 22

B

#2 22

27

2 23 24 5 26

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Cut # 2

Figure 25.6â•‡ Cheese bite with the negative impression of the teeth (A), the positive profiles created with horizontal slices through the positive model (cuts 1 and 2), and the suspect dentition (B).

25.2.5â•…Identical Substances Numerous papers have been published concerning bitemarks in foodstuffs and other inanimate objects. Pieces of cheese [9–12], soft cake [13], chocolate [14], chewing gum [15], a sandwich [16], and soap [17] have been collected as evidence and presented as case reports. Test bites into similar objects should be attempted using a duplicate set of dental models. Models can be partially protected from damage to some degree by coating them with an air-thinned layer of cyanoacrylate, liquid floor wax, or fingernail hardener. In most of the cited cases (chewing gum excepted), incisive bites predominate with the facial configuration (outline or profile) of the teeth recorded. With chewing gum, the posterior occlusal surfaces of teeth are usually captured. With all of these substances, a replica can be created using an impression made of the original object. These are considered the negative representations of the biting teeth. From the negative, a model of the positive profile can be fabricated and compared to the suspect dentition. FigureÂ€25.6 illustrates the profile comparison technique. 25.2.6â•…A nimal Skin Porcine (pig) skin has been used as a substitute for human skin in creating test bites [18,19]. These studies used the pigskin after the animal had been sacrificed and the tissue resected, rather than making the test bite

25.2.8â•…Dynamic Test Bites on a Volunteer A test bite created on a human volunteer is considered dynamic owing to observable interplay of tissue and teeth and the potential of observation of healing tissue when sufficient force has been applied. The goal is to create a facsimile of the original bitemark for comparative study. The most common method of creating test bites uses dental models (stone, acrylic, or Vitalium®) attached to a Vicegrip® or mounted on a dental articulator, or biting the volunteer directly to the maximum degree of subject tolerance. The resultant bitemarks are usually short-lived, and evidence of tissue damage and bruising is quite minimal if present at all. Harvey et al. discuss the creation of test bites on volunteers who were bitten under general anesthesia in an operating room [29]. In the study, the biters used their own natural dentition to create the bitemarks. Even when goaded to make a more severe mark, the biters could not generate tissue damage to the extent commonly seen with real bitemarks. Harvey et al. related this finding to the psychological state of the criminal biter and any simultaneous response by the victim at the moment of the injury. Another recent study [30] mimicked test results of short-lived bitemarks and little evidence of tissue damage or bruising on an unanesthetized volunteer. When test bites are created on a volunteer’s skin, it is important to consider the influence of the complex bouillabaisse of variables that affect the appearance of any injury created. Most of the variables that contribute to the bitemark injury are interdependent. With test bites, the applicable variables can only be correlated to each individual bite at that anatomic location, at that moment in time, and by the force creating the mark, not to mention other variables mentioned elsewhere in this textbook. Dailey and Bowers published a literature review enumerating the variables affecting the appearance of bruises other than bitemarks and a comparison chart

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473

Missing Tooth = No Mark

Figure 25.7â•‡ The migration and expansion of a bruise: days 1 and 4.

of the previously published time-related color changes observed with healing bruises [31]. The processes of wound healing are poorly understood—even less so as applied to bitemarks in particular (see the histology and the research chapters in this edition for further information). Any or all of the 19 published variables involved in the evolution, appearance, and eventual degradation or disappearance of bruises are certainly in play for bitemarks and may even vary among multiple bitemarks on the same victim. Furthermore, quantifiable conclusions related to the appearance of such injuries are examiner dependent, since color discrimination is widely variable between members of the human race. FigureÂ€25.7 demonstrates the difference in the appearance of a bruise on a shoulder on the first and fourth days of healing. The color change is minimal, yet the expansion and migration of the bruise are significant. Since no scientific ruler was included, the author used triangulation of the anatomically stable nevi to establish and confirm accurate sizing between the two photos. As would be expected, the direct comparison of static test bites with dynamic test bites yields both similar and discrepant findings. It has been demonstrated that transparent dental overlays made from test bites of the same dental model in wax, in Styrofoam, and on skin will not be identical [32]. This is primarily due to the flat configuration and rigid nature of the two former test materials versus the near-infinite configuration of the skin’s surface and its elastic and compressible character.

25.3â•…Direct Comparison 25.3.1â•…Suspect Biter and the Excised Tissue Using Dorion’s type V excision technique (described in this textbook), direct apposition and comparison as well as metric analysis with and without transillumination

Figure 25.8â•‡ The biter’s stone dental model compared

directly to the excised bitemark. (Photo courtesy of Dr. Robert Dorion.)

can be realized (FigureÂ€ 25.8). Additionally, the comparison of the models to the tissue can be videotaped or photographed to create a courtroom presentation. Photographs made of the transilluminated tissue injury have additional advantages over the conventional overlay comparison. 25.3.2â•…Suspect Biter and the Bitemark Impression When impressions are made of the tissue injury, the replicas can be compared directly to the suspected biter’s dental models. Where significant tooth indentations are present in the bitemark, the incisal edges of the stone teeth can often be placed directly into their corresponding negative configuration on the bitemark replica. In cases of dramatic tissue indenting, the biting edges of some teeth may be positioned above the horizontal plane and distant to the stone bitemark model (FigureÂ€25.9). This can be explained by the elasticity of tissue as compared to the noncompressibility of the stone model. Using a set polyvinylsiloxane bitemark model instead of stone can mimic slight tissue compressibility.

25.4â•…Dental Nomenclature Authorities should routinely collect the suspected biter’s complete dental records. The records may include documentation of tooth numbering different from the one currently used by the examiner. This is commonplace when records are obtained from outside the United States. Consequently, it behooves the examiner to be cognizant of such possibilities and have ready access to information explaining the various tooth numbering systems. The appendices in this edition present comparative dental nomenclatures for the primary and secondary dentitions.

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7

10

c

Figure 25.9â•‡ Teeth 7 and 10 are above the horizontal plane

of the other anterior teeth and do not approximate the indentations created in the original bitemark. The curvature of the bitten surface (an arm) is demonstrated by (c).

25.5â•…Inverting Cast (Flip Horizontal) for Comparison One of the most difficult concepts for the forensic dental neophyte, trier of fact, and the jury is the concept of “sidedness” in relating teeth to bitemark. While this point may seem mundane to the dentist looking at a patient’s dentition through a mirror, bitemark versus dentition may be confusing. The dental health professionals (dentist, dental specialists, dental nurse, dental hygienist, etc.) think opposite sides when seeing through a dental mirror. However, the tendency for the forensic dental neophyte is to see the bitemark as a patient, thus reversing sides. If, instead, the investigator thinks of himself or herself as the biter, then bitemark sidedness does not become an issue. The concept, however, has to be related in a written report and to the trier of fact and the jury. The use of a transparent overlay—a clear acetate sheet outlining the hand-drawn dental incisal edges— was a common comparison method with bitemark photographs. Overlay sidedness can be an issue. To avoid confusion, the overlay should be clearly marked with an “R” and/or “L,” for right- and left-sided dental quadrants. If the acetate is flipped, the letters will be also. Other overlays are created using photocopiers, flatbed scanners, or digital cameras to capture the incisal/occlusal edges of the dentition or dental models. Regardless of the technique used to make dental overlays from dental models, an unwritten convention has developed among forensic dentists to place an ABFO no. 2 scale alongside the models. This automatically resolves sidedness issues.

Flipped to Coincide with Bitemark

Figure 25.10â•‡ Scanned maxillary model indicating left and right sides (upper) and flipped horizontally (lower).

There are other ways of maintaining the proper orientation throughout an analysis. Another technique takes advantage of the large depth of field utilized by photocopiers and scanners during image capture. The letters “L” and “R” can be inscribed on the model distant from the dental structures (FigureÂ€25.10). Alternatively, photographs can be taken reflected into a mirror (FigureÂ€25.11). Without proper image labeling, during the stress of testimony, it is easy to become confused about sidedness while attempting to demonstrate the relationship of transparent overlays to bitemark photographs. Additionally, the exemplars, which now become court exhibits, should not confuse the trier of fact or members of the jury. Many expert witnesses currently prefer to use video or a PowerPoint® or Photoshop® (Adobe Systems Incorporated, Seattle, Washington, Version 7.0, hereafter referred to as Photoshop) presentation rather than a hands-on demonstration of dental acetate overlay to bitemark photograph. The latter becomes part of the court record/exhibit. Whatever the means may be,

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(a)

#22

(b)

Looking at the Patient

6

7

27

8

26

9

25

24

10

23

11

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Figure 25.11â•‡ Dental models (foreground to the right) seen

through a mirror (top). Dental models in normal view identified with the universal dental nomenclature (bottom).

successful analysis and presentation of bitemark evidence can be minimized when steps are taken to prevent confusion over sidedness.

25.6â•…Overlays 25.6.1â•…Simple Overlays Historically, the most common method of recording bitemark evidence is through two-dimensional photographs. A straightforward method to relate the biting edges of a suspected biter’s dentition to the bitemark photograph is with a dental overlay. These are generally colorless, transparent acetate sheets containing information transferred by the examiner from the dental models either by hand or electronically. The goal of the various overlay techniques is to capture the biting edges of the teeth as objectively as possible. Overlays can be made to demonstrate the outlined edges of the teeth (hollow-volume overlays), or the edges can be filled in (filled-volume overlays). Additionally, the actual tooth

(c)

Figure 25.12â•‡ Hollow volume overlay (a), filled volume overlay (b), and compound overlay (c).

image, either solid or semitransparent, can be captured within the outline (compound overlay). The three types are illustrated in FigureÂ€25.12. Originally, the acetate sheets were placed directly on the edges of the dental models and the examiner marked the outline of the incisal edges by hand in indelible ink. The overlay was then laid onto the bitemark photograph for comparison. From this very unsophisticated and subjective beginning, forensic dentists have developed other methods for greater accuracy and reproducibility and have published and/or presented them at scientific meetings. Such a technique uses radiographic plates made by placing amalgam powder, barium sulfate, or other radio-opaque substances into indentations created by tooth edges in wax, plaster, or other materials. Another recent technique inks the incisal edges with what the author calls “invisible” fluorescent ink [33]. It blends simple and computer-generated techniques discussed in the next section of this chapter. At the opposite extreme is a photographic technique that is time and labor intensive [34] and that utilizes computed tomography (CT) scans [35].

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Right Case: M.N. JCD: 04-04-2003

Figure 25.13â•‡ A transparent dental overlay created with Dailey’s photocopy technique and showing a wear facet on tooth 11.

When this author published a photocopy technique for bitemark overlay fabrication [36], the ubiquitous photocopy machine was employed to produce a quick, accurate, and inexpensive dental model image. This copy is placed image side down onto an x-ray viewer and the examiner traces the incisal outlines. The outlined image is then photocopied and printed on a clear acetate sheet with an ABFO no. 2 scale, producing a hollow-volume overlay, as shown in FigureÂ€25.13. In the illustration, a small circle is visible within the traced outline of the worn left canine, tooth 11. This subtle characteristic may not be captured by other methods, such as computergenerated overlays. 25.6.2â•…Computer-Generated Overlays The search for the “Holy Grail” moved from photocopy machine to computer. Forensic dentists discovered graphic art software that could enhance bitemark photographs and produce overlays. While numerous programs are available, Photoshop will be discussed since it is the most widely used by forensic dentists. A graphics tablet facilitates greater operator control in Photoshop, ensures economy of motion, and provides for operator ergonomics. A pen is a substitute for the conventional mouse, finger mouse pad, or miniature joystick. Its controls can be customized by the operator, allowing for more precision than conventional alternatives do. The significance of quick and precise

Figure 25.14â•‡ A transparent computer-generated dental overlay showing the pixilated tooth outlines.

pixel selection with this device is plainly apparent from first use. Computer-generated overlays outline the biting edges of teeth (FigureÂ€25.14). Some present as irregularly pixilated shapes that barely look like the tooth edges it purports to represent (FigureÂ€25.15). Naru and Dykes [37,38] introduced the fabrication of computer-generated overlays to forensic odontology in 1996. While innovative, this method required the examiner to adjust the image brightness and contrast (a subjective interpretation) in order to facilitate selection of tooth edges—a technique known as “edge detection.” It was printed on clear acetate sheets, producing an overlay. The promoters described a very small-scale study conducted to test interoperator reproducibility by providing identical images to each candidate. According to the authors, the candidates were able to generate identical overlays; this was not the case and the process did not reduce subjectivity. Several authors have published on the fabrication of computer-generated overlays using Photoshop [39–42].

Methods of Comparison

477

(a)

(b)

(c)

(d)

Figure 25.15â•‡ A demonstration of the variability of the results created by the MWST in Photoshop when two adjacent pixels are selected.

There is an apparent disagreement concerning the degree of subjectivity in using the technique. The primary issue concerns the selection of the biting edges of the teeth with the magic wand selection tool (MWST) resident to the Photoshop software. After establishing the settings, the examiner selects pixel outlines for the incisal edges of each anterior tooth. The decisions of where to select and when to stop selecting pixels are subjective decisions. This process may involve dozens to hundreds of keystrokes, depending on operator ability. Because of variations in the quality and temperature of each image imported from different scanners into Photoshop, the examiner must frequently adjust the brightness and contrast before the MWST process can begin. This is another subjective decision. The issue with MWST subjectivity highlights the lack of interand intraoperator reproducibility. The avocation of the use of the history palate in Photoshop is presented as a method of archiving the steps taken by an examiner while enhancing an image. While this is necessary, the use of this tool is fraught with problems for several reasons: The user must be knowledgeable in altering the software presets under “Preferences” in Photoshop. If not, the default settings for history information are set such that the information exists only as long as the image is open; that is, the history information is discarded when the image file is closed. Therefore, in order to save and archive the history list of operations done to an image—or “states,” as operations are called—the list of history states must be recorded elsewhere by the examiner or the program. It may be necessary to keep careful track of what has been done to a file in Photoshop for the examiner’s records, client records, or legal purposes. In more recent versions of Photoshop, the edit history log helps to keep a textual history of changes made to an image. By default, history log data about each session are saved as metadata embedded in the image file where the history log data are saved and the level of detail contained in the history log can be specified. The edit history log metadata can be reviewed using Adobe Bridge or the file info dialog box. If it is necessary to prove that the log file has not been tampered with, the edit log should be kept in the file’s metadata; Adobe Acrobat can then be used to sign the log file digitally. • The examiner must establish a preference setting in the program to tell Photoshop how many history states to record. If the program’s default of 20 is used, when the 21st state is created, the

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first state (operation no. 1) will be eliminated from the top of the list. This is easily corrected since the examiner is allowed to create a preference setting of up to 1,000 saved history states. More history states require more memory, so if computer temporary memory, or RAM, is minimal, a much smaller number of history states will be the rule. • Undoubtedly, the most significant point to discuss about the history palate concerns what is actually being recorded with each operation performed. The information recorded concerns only what the keystroke did, such as inverting the image, making a selection with the MWST, and so on. With selections made by the MWST, the pixel selected at that moment is not recorded. This strikes to the heart of the reproducibility issue: Every overlay must have the exact pixels selected every time, by every operator. For this to occur between two examiners would require an astronomical degree of luck. Figure 25.15 demonstrates the difference in pixel selection when the MWST is moved only one pixel apart during the selection process. In (a), the life-size (100%) view of the image is seen on the computer screen to demonstrate the minute size of the two adjacent pixels that are bounded in black. When the examiner uses the MWST with the life-size image or even the 200% image (twice life size), the size of the tool on the screen blocks the pixel selection from the examiner’s view. In (b) the image has been enlarged to the maximum size possible (1600%) in Photoshop to show the two pixels. When the MWST is touched to the rightside pixel (c), that one keystroke selected only the one chosen pixel. When the left-side pixel was touched with the MWST, hundreds of pixels across two tooth edges were chosen (d). This is easily illustrated at the 1600% magnification possible in Photoshop; however, when the image is that magnified, the examiner loses perspective and orientation. There is no happy median. The contention that computer overlay fabrication increases interoperator and intraoperator reliability and reproducibility is incorrect. Reconsidering Naru and Dykes’s study of operator variability, the issue previously raised concerning achieving nearly identical results becomes significant when reconsidered in a different light. Consider a technique that was accurate and reproducible at each step and that allowed a permanent record to be made of each

step that could be passed between experts, similar to the passing of photographic and dental model evidence, as is currently done. If the computer-generated overlay could be created with only one selection click of the MWST in Photoshop, regardless of where on a group of teeth the tool was placed, would all of the criticism and discussion of subjectivity disappear? The answer should be yes. What follows is such a technique. A technique was developed to allow stone dental models to be enveloped in a contrasting color [43]. This has been shown to eliminate subjectivity in biting edge selection. In Figure 25.16, the anterior incisal plane of the dental model is identified by scoring each of the three tooth edges that create that plane in space with a red dot. A flat-plane denture tooth setting plate is affixed to the model at the three red points. The model and plate are placed in a retaining receptacle, and an enveloping layer of a contrasting color stone is poured around the original model (Flowstone, Whip Mix Dental Product, Louisville, Kentucky).

Figure 25.16 The horizontal plane created by three anterior tooth contacts and marked by a red dot in the maxillary and mandibular dentition.

Methods of Comparison

479

Figure 25.17â•‡ The three red dots at the surface of the horizontal plane and recorded in the enveloping stone layer.

Figure 25.19â•‡ The transparent enveloped overlay.

#24

Figure 25.18â•‡ MWST use for outline selection for all six maxillary anterior teeth in the enveloped model.

When the enveloping stone sets and the flat-plane plate is removed, the three red dots are seen at the stone surface (FigureÂ€ 25.17). Next, the opposite side of the model is cut parallel to the plane of occlusion on an orthodontic model trimmer. With the base now parallel to the plane, the model is turned toward the cutting wheel and trimmed sequentially in 1-mm cuts. The models are dried and scanned into Photoshop. All tooth edges are selected simultaneously with a single keystroke of the MWST because of the difference in color (FigureÂ€25.18). FigureÂ€25.19 represents the final envelopment overlay.

#25

Layer 4

Figure 25.20â•‡ A V-shaped notch on the edge of tooth 25 is clearly demonstrated by this cut into the enveloped model, while tooth 24 is not yet visible (see also Figure 25.24).

As often happens in research, a tangential finding showed that discrepant horizontal alignment of teeth could produce irregular shapes and sizes, such as a V-shaped notch (FigureÂ€25.20), at different levels of cut (see also FigureÂ€25.24). When these sequential cuts were stacked upon each other in Photoshop, a topographic map of the teeth was created. This has also been referred

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

First Cut Second Cut Third Cut Fourth Cut

Figure 25.21â•‡ The maxillary topographic overlay.

to as a pseudo-CT technique. A combined topographic overlay is presented in FigureÂ€25.21. If several duplicated models were simultaneously enveloped using this technique and the entire sequential series of models could then be given to all examiners for a one-keystroke operation for each overlay, it could end the debate over inter- and intraoperator reproducibility. As demonstrated, there are several methods for creating accurate overlays. FigureÂ€ 25.22 summarizes #10

1a #10 2a

the envelopment technique (1a, 1b), the photocopy technique (2a, 2b), the computer-generated technique (3a, 3b), comparison to the dental models (4), and the bitemark photograph (5). With the development of a technique that allows all examiners to analyze the same layers recorded in stone objectively, the debate over variations between overlay fabrication techniques should subside. The direction of future research should be aggressively pursued toward tissue-healing dynamics and the gleaning of additional evidence from bitemark photographic techniques not currently recognized. The creation of objective overlays is well intentioned, but transfer of dental detail to skin is another story altogether. Importantly, this does not preclude an analytical comparison of the overlay to the patterned injury. FigureÂ€25.23 demonstrates a high degree of correlation of mandibular teeth transfer to skin in both overlays (a, b). The maxillary teeth were less accurately correlated, but the fit of all overlays was similar to that of the topographic overlay (see the research section in this edition for further information on the reasons for these findings). However, rotation of the overlay around the fulcrum point at the tip of the arrow between the central incisors aligns teeth numbers 1–8 in (a) and 9–6 in (b). Such demonstrations and their explanations allow the trier of fact to decide the weight of the evidence. Concomitant with the various methods of comparison previously discussed, the forensic odontologist will already have performed, where applicable, a metric analysis of the bitemark. Ultimately, the comparison leads to a conclusion of whether there is proximate cause between bitemark and the suspect dentition. The current ABFO terminology to relate a suspected biter to a bitemark is in the Appendix 1.

#10

25.7â•…Metric Analysis

3a

3b #23

5

2b

1b

#23

4

#23

Figure 25.22â•‡ Comparison of the three methods of transparent dental overlay with the bitemark photograph.

A metric analysis is performed on the bitemark or bitemarks (the singular will be used henceforth) and suspected dentition or dentitions (the singular will be used henceforth) independently one from the other. The goal of the metric analysis is to ascertain as much quantitative information about the suspect dentition and the patterned injury as possible. For the dentition, the size of each tooth (metric measÂ�ureÂ�ment) within both dental arches (spatial relationship to all others including occlusion and horizontal plane) is required. This is usually accomplished directly from the suspect’s dental stone models or from sample bites. Additionally, measÂ�ureÂ� ments in the third plane can be recorded (FigureÂ€25.24).

Methods of Comparison

481 4

5

1 mm

3

Hand Drawn Overlay

B 5

5

4

A

4

3

3

2

First Cut Second Cut Third Cut Fourth Cut

2

2

1 mm

mm 1

Computer Generated Overlay

Figure 25.23â•‡ Maxillary topographic overlays shown with mandibular overlays produced by Dailey’s photocopy technique (a) and the computer-generated technique (b).

b

a #24

#25

Figure 25.24â•‡ Two (a) of the three teeth making up the horizontal plane (b), and the relationship of all of the other incisal edges.

Calipers, rulers, compasses, protractors, and other instruments have been used for metric analysis with great success [44]. Recently, digital metric analysis has facilitated the task without sacrificing accuracy. While computers are pervasive in today’s world, a form of what Dr. Thomas R. O’Connor called “digital divide” can exist between the old and the new [45]. The manual methods of metric analysis are tried and true, and these old ways still work well. Initially, however, identifying the maxillary from the mandibular teeth represented in the bitemark will orient the bitemark. Finally, the mesial-to-distal width and degree of rotation from the x-axis or y-axis will be recorded for each tooth represented in the bitemark.

25.8â•…Digital Analysis The digital tools available in Photoshop and other software programs allow for accurate measÂ�ureÂ�ment of width and angulation [42,46,47]. FigureÂ€ 25.25 demonstrates the digital metric analyses from the dental models and the scanned-inverted digital image of its wax bite. While the angles of the teeth to the x-axis are the same,

the mesiodistal widths are different. This finding relates to the earlier discussion of depth recording in wax. Additionally, images can easily be enhanced; this requires little time and effort compared to darkroom techniques. A color image can now be screened by individual color channel, converted to gray scale, changed for brightness or contrast, and inverted—all with a few keystrokes. It is imperative that the untouched archival original images remain untouched (see Chapter 7).

25.9â•…Other Comparison Techniques 25.9.1â•…Pattern Analysis in Three Dimensions Pretty [48] has stated, “Indeed, it could be argued that most biologic features are unique if measÂ�ured with sufficient resolution.” This statement seems validated when one reviews the SEM images of the incisal edges of teeth as recorded in selected bitemark cases. True three-dimensional comparisons—direct dental cast apposition/comparison to the tissue or with model of the tissue—are infrequent for the reasons discussed throughout this edition. Pseudo three-dimensional computer image visÂ� ualization software is changing the way forensic scientists, the triers of fact, and juries see the evidence. Pathology, questioned documents, fingerprints, bitemarks, ballistics, crime scene analysis, and accident reconstruction have all used some form of this emerging technology. Measurement of internal consistencies software (MICS) from Limbic Systems (Bellingham, Washington) displays all 256 shades of gray (the human eye perceives fewer than 50). MICS allows viewing of two-dimensional images as pseudo three-dimensional images. FigureÂ€ 25.26 is an MICS enhancement of an original black-and-white bitemark photograph that appeared in the first edition of this

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

Figure 25.25â•‡ The metric information for the anterior teeth from dental models (left) and wax bites (right). Density 255 191 128 64 0

Figure 25.26â•‡ A pseudo three-dimensional image created from the original grayscale bitemark photograph using the MICS software.

book (2005). A subsequent paper discussing a similar technique using Photoshop, labeled the pseudo threedimensional approach as image perception technology, appeared in 2006 [49]. True three-dimensional scanning, using either touch-probe digitization scanning or laser-scanning, has been utilized in bitemark analysis and comparison bench studies [50–52] in an ongoing search for applicable CAD-CAM hardware and software that will capture real dental models, recreate virtual dental models, and generate slices at various levels in horizontal profile. In the third study cited, video animation of the comparison process is discussed. Due to the theatrical potential of such high-tech approaches to bitemark analysis and comparison, acceptance for admissibility in court should occur only after extensive research verifying the reliability and reproducibility of these methods. The

Methods of Comparison

authors of the aforementioned papers are to be complimented for discussing the limitations of the techniques. The continuing research of the touch-probe technique has resulted in follow-up papers discussing the need for further refinement of computer-based methods of image processing and demonstrating the technique to be applicable only when tooth indentations are present in the bitemark—a rare occurrence, as discussed previously [53,54].

483

A

25.9.2â•…Videotape The use of videotape in an attempt to demonstrate the dynamics of the biting event has been published in the forensic literature [55]. Such reenactments should be kept as simple as possible and limited to the obvious facts as recorded in the evidence. Videotape is also a useful way for the expert to demonstrate to the trier of fact the sequence of steps taken during the various comparison techniques utilized for bitemark analysis.

B

C

25.9.3â•…Ink Immersion Technique The ink immersion technique, which involves placing a stone dental model into a bowl or other receptacle, is used at the University of Queensland, Australia. Black ink is slowly poured into the receptacle and videotaping is used to record the ink slowly covering the teeth until all tooth edges disappear. The video is then viewed in reverse to simulate first tooth edge contact to last tooth edge contact. This is claimed to be relatable to the premise that the earlier the contact is, the greater is the extent of the subsequent injury observed in the bitemark injury. While this approach seems logical, there is not yet any scientific proof to substantiate the validity of this hypothesis. Also, the inter- and intraexaminer reproducibility required of such techniques has not yet been demonstrated. FigureÂ€25.27 is a photographic representation of the technique: Teeth strike the tissue (A); sequentially, more teeth surfaces engage the tissue (E). 25.9.4â•…The Dental Line-Up There are situations in which all potential biters are known—a closed population scenario. In such cases, the forensic dentist has a viable comparison option that does not exist with an open-population situation: the dental line-up. Test bites of all members of the closed population are arranged next to each other and visualized as a group. The goal is to identify one pattern exhibiting great similarity to the bitemark. This special circumstance has an added advantage. If there is an absence of a scale in the bitemark photograph and no measurable

D

Figure 25.27â•‡ The ink immersion technique, simplified in serial time photography, demonstrating the successive tooth contact in the creation of a bitemark.

references (FigureÂ€ 25.29), there are scaled comparative dental models. Which one fits best to the bitemark? FigureÂ€25.28 depicts a dental line-up of four suspect dentitions recorded in Aluwax. “B” presents a pattern quite similar to the injury, while “A,” “C,” and “D” can be excluded as biters. Individual “B” is included as the probable biter because metric analysis and comparison between wax bite and bitemark can be layered in Photoshop. When one considers the strength of such analysis, without a scale for life-sizing the evidentiary image, the expert opinion must be conservative. That said, with appropriate education of the trier of fact, it should be possible to apply the appropriate weight to this limited, but useful, comparison technique.

484

Bitemark Evidence: A Color Atlas and Text, 2nd Edition #9 #8

#9 #8

#9 #8 #11

Tooth #11 #5 missing

#11

A

#H#11D #5

#5 C

B

#F/9D-#E/8D

#B/5D D

Figure 25.28â•‡ The wax bites from four suspects in a dental line-up.

Figure 25.29â•‡ The bitemark to be compared to the dental line-up in the previous figure.

25.9.5â•…Other Methods of ComputerAided Visualization In FigureÂ€ 25.30, the maxillary wax wafer sample bite (center) has been layered onto the bitemark photograph (upper right) and the inverted bitemark image in Photoshop. The opacity of the image of the wax wafer has been lowered to allow the bitemark to show through.

25.10â•…Pattern Recognition Ability A 2007 article in Time magazine stated, “The human brain is designed to seek out patterns” [56]. Throughout evolution, an individual’s survival depended upon

recognition of patterns. Visual pattern recognition allowed for identification of threats before they could produce fatal results. The correct identification of dangerous flora and fauna made survival more likely. Not all humans have the same abilities or skill sets. All have varying degrees of innate abilities and learned abilities. It would seem fair to say that no two humans are identical in cognitive abilities. Cognition is the psychological concept that refers to such processes as perceiving, knowing, recognizing, conceptualizing, judging, and reasoning. The logical extension of the preceding discussion is that not all humans recognize patterns equally well; bitemark patterned injuries are no exception. Forensic dentistry has recently been tasked, in a report by the National Academy of Sciences, with improving the scientific reliability of bitemark analysis [57]. One has to wonder if there is some scientifically measurable biologic basis responsible for the conclusion by the NAS that “wide variability exists across forensic science disciplines with regard to techniques, methodologies, reliability, error rates, reporting, underlying research, general acceptability, and the educational background of its practitioners.” In focusing on forensic odontology, the report stated, “In numerous instances, experts diverge widely in their evaluations of the same bitemark evidence, which has led to questioning of the value and scientific objectivity of such evidence.” Until proven otherwise, it is this author’s opinion that there is a logical explanation beyond the claim of experiential differences between examiners for the aforementioned widely divergent conclusions between forensic dentists examining the same evidence. In part, that explanation is variations in the visual acuity of

Methods of Comparison

485

Figure 25.30 A bitemark photograph (upper left), negative image (lower left), with the wax bite semitransparent layer (upper right, lower right).

those practicing patterned injury analyses. Perhaps this explains why published studies have shown a wide range of results in the ability to analyze bitemarks between nondentists, neophyte dentists, and board-certified forensic dentists, as well as within the members of each group [58–60]. Such studies were initial investigations that were done with minimal consideration and inclusion of the myriad variables between and within these groups that may have contributed to the results and subsequent conclusions. None of these publications considered or studied the visual acuity of the individual participants and, therefore, between the groups. To their credit, these studies recommended further research into why the observed variations from the expected results occurred. I am suggesting that the difference between examiners in these studies was due, in some measure, to visual acuity (the ability to see) affecting the concomitant related biological and psychological processing of that visual data (the pattern seen). Subsequent perception and interpretation of the data may be singularly experiential, but scientific studies need to be developed that test those who wish to

perform bitemark patterned injury analysis. At a minimum, such visual acuity and pattern recognition studies need to be developed under the guidance and auspices of neurologists, psychologists, and optometrists, or ophthalmologists. Once it is developed, the American Board of Forensic Odontology can administer required testing. One result of such testing—and a finding of validity in the concept of biologic differences in the innate ability to see patterns—will be the creation of a board-certified subspecialty of forensic dentistry for those who will be separately certified to perform patterned injury analysis. Others will be able to become board-certified forensic dentists, only without this subspecialty. Research into a heretofore unimagined biologic basis for unexplainable differences in conclusions and opinions between otherwise equally experienced forensic dentists will serve to bring our specialty into compliance with the recommendations of the NAS report. Specifically, “more research is needed to confirm the fundamental basis for the science of bite mark comparison.” While the NAS report was referring directly to research into the uniqueness of human dentition, the ability of that dentition to transfer unique characteristics

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

to the skin, and distortion issues within the skin, this author feels that the report’s authors were unknowingly prophetic.

25.11 Conclusion There are advantages and disadvantages for each method of comparison during the bitemark analysis process. At this time, there is not one all-encompassing method for the comparison of bitemark patterned injury evidence with that from a suspected biter. The standard among forensic odontologists is to use two methods of comparison in the analysis process. Owing to the generally heinous nature of crimes that produce bitemark evidence and the concomitant severity of the punishment to be meted out with a guilty verdict, two methods of comparison should be considered the minimum for the analysis of such cases, rather than the recommended requirement. Currently, looking at a photograph of a bitemark injury is analogous to looking at a photograph of a home run being hit during the World Series or the running of the bulls in Pamplona, Spain. That is, an event that occurs over a period of time, in a known spatial location, and in three dimensions is captured as a single frozen moment in time of extremely short duration and reduced to a two-dimensional photograph. While the picture may tell a very compelling story and reveal a wealth of information about the event it depicts, it cannot reveal everything related to the circumstances that were occurring before, during, and after the moment the photograph was made. An important point is raised by this analogy. Forensic odontologists know there is often a wealth of information available within each piece of evidence that goes unrecognized or unused because the techniques or technology have yet to be discovered to allow its utilization. It is a fact that we are not yet able to use all of the available evidence recorded in the patterned injury. Critics claim that bitemark patterned injury analysis is not yet founded on adequate scientific research. It is important to remember that pattern recognition is something the human brain is genetically wired to do thousands, if not millions, of times per day. During the reading of this book, each word is recorded as an image by the eyes and transmitted to the brain, where it is recognized first as a printed word, rather than as an image of a flower, an animal, a glass of wine, or a loved one; the exact word is then recalled; and, finally, its meaning and the context are registered in the conscious mind of each individual. Additionally, most images in this textbook have short, one- or two-sentence legends, yet the readers are capable of discerning many additional facts from those

images. The readers will undoubtedly formulate opinions related to the image quality (such as clarity, contrast, and adequate size of the area of concern in the photo), as well as appropriateness for inclusion as an illustration of the point being presented by the author. Finally, they will search the images for information unrelated to the discussion at hand. Humans are, by nature, good at solving puzzles. Most readers have had some experience at putting together jigsaw puzzles. They have been able to look at the photograph of the soon-to-be-completed image on the box cover, review the work in progress before them, formulate a mental image of the shape or pattern of the next piece to be searched for, and then scan across dozens or even hundreds of puzzle pieces scattered at random on the tabletop to successfully find the needed piece and slip it into place. With rapidly advancing information technology delivery systems invading every aspect of human life, most people have observed video images from surveillance cameras recording a crime in progress at a bank, convenience store, or other crime scene. While the quality of these images is poor compared to well-focused photographic images, associations with the perpetrators of the crimes are usually quite easily made by individuals trained to recognize the facial patterns and other telltale characteristics of humans. It is important that such associations are often made just as easily by the untrained watching these videos on television or via the Internet. There is validity to the discussion that the experience and training of the examiner of a bitemark patterned injury is crucial to the successful outcome of the analysis, as well as the convention that it is better to be conservative in the approach to an analysis and the final opinions rendered concerning the value of the bitemark evidence and the correlation with any suspected biters. What is not valid is the argument that bitemark analysis is totally subjective and does not belong in a court of law. As long as the bitemark evidence recovered from the victim is of high quality and the examiner is thorough in his or her analysis and conservative in his or her conclusions, such analysis is a valuable tool for the courts. If such evidence and the analysis are obvious, logical, and understandable to the trier of fact, they should be admissible and the appropriate weight should be given to that evidence. A common recurring question in this arena asks if bitemark patterned injuries are unique enough to allow individualization (segregation) of the causative dentition from among the pool of suspected biters developed by the investigating authorities. Importantly, research in this direction is beginning to take place in the field of forensic odontology. Admissions of guilt by suspected biters,

Methods of Comparison

concurrent DNA evidence, observed biting, and other means of authenticating “gold standard” (i.e., “known”) bitemarks validate many successful bitemark analyses. Another area of frequent discussion involves the accuracy of the evidence when the events surrounding the moment of the bite are unknown. Unless the recipient of the bite survives his or her assault and can duplicate, via demonstration, the exact spatial position of the bitten area of his or her anatomy at the moment of the bite, the examiner will never know the true circumstances surrounding the event. Therefore, when the bite evidence is recorded in all other situations, the photographs and impressions of the patterned injury will be captured with the tissue in a position most likely discrepant from that at the moment of injury infliction. When Harvey discussed experimental human bitemarks in his textbook, published over a quarter of a century ago and apparently forgotten by a new generation of forensic scientists, he stated that, while discrepancies created by positional changes of the body do occur, unique characteristics that exist within the pattern, “which can be clearly recognized throughout changes in posture,” would still be clearly ascertainable to the examiner [61]. Harvey also stated that while “superimposition is negated, it is also superfluous.” This is the fundamental principle that will ensure the viability of bitemark patterned injury analysis in our legal system. It seems illogical that controversy should exist if the quality of the evidence is high, the pattern demonstrates unique characteristics that can be correlated to a suspect biter’s dentition, and the conclusions derived from the bitemark analysis are conservative.

References 1. Committee on Identifying the Needs of the Forensic Sciences Community, National Research Council. 2009. Strengthening forensic science in the United States: A path forward. Washington, D.C.: National Academies Press. 2. McKinstry, R. E. 1995. Resin dental models as an aid in bite mark identification. Journal of Forensic Sciences 40:300–302. 3. McKenna, C. J., M. I. Haron, and J. A. Taylor. 1999. Evaluation of a bitemark using clear acrylic replicas of the suspect’s dentition—A case report. Journal of Forensic Odontology 17:40–43. 4. Wright, F. D., and J. C. Dailey. 2001. Human bite marks in forensic dentistry. Dental Clinics of North America 45:365–397. 5. American Board of Forensic Odontology. 1997. ABFO guidelines and standards. In Manual of forensic odontology, 3rd ed., ed. C. M. Bowers and G. L. Bell, 338–341. Colorado Springs, CO: American Society of Forensic Odontology.

487 6. American Board of Forensic Odontology. 1997. ABFO guidelines and standards. In Manual of forensic odontology, 3rd ed., ed. C. M. Bowers and G. L. Bell, 337. Colorado Springs, CO: American Society of Forensic Odontology. 7. American Board of Forensic Odontology. 1997. ABFO guidelines and standards. In Manual of forensic odontology, 3rd ed., ed. C. M. Bowers and G. L. Bell, 338. Colorado Springs, CO: American Society of Forensic Odontology. 8. Wright, F. D., and J. C. Dailey. 2001. Human bite marks in forensic dentistry. Dental Clinics of North America 45:365–397. 9. Layton, J. J. 1966. Identification from a bite mark in cheese. Journal of Forensic Science Society 6:76–80. 10. Sweet, D., and D. Hildebrand. 1999. Saliva from cheese bite yields DNA profile of burglar: A case report. International Journal of Legal Medicine 112:201–203. 11. Bernitz, H., S. E. Piper, T. Solheim, et al. 2000. Comparison of bitemarks left in foodstuffs with models of the suspects’ dentitions as a means of identifying a perpetrator. Journal of Forensic Odontology 18:27–31. 12. Bernitz, H., and B. A. Kloppers. 2002. Comparison microscope identification of a cheese bitemark: A case report. Journal of Forensic Odontology 20:13–16. 13. Aboshi, H., J. A. Taylor, T. Takei, and K. A. Brown. 1994. Comparison of bitemarks in foodstuffs by computer imaging: A case report. Journal of Forensic Odontology 2:41–44. 14. McKenna, C. J., M. I. Haron, K. A. Brown, et al. 2000. Bitemarks in chocolate: A case report. Journal of Forensic Odontology 18:10–14. 15. Nambiar, P., G. Carson, J. A. Taylor, and K. A. Brown. 2001. Identification from a bitemark in a wad of chewing gum. Journal of Forensic Odontology 19:5–8. 16. Simon, A., H. Jordan, and K. Pforte. 1974. Successful Identification of a bite mark in a sandwich. International Journal of Forensic Dentistry 2:17–21. 17. Corbett, M. E., and D. A. Spence. 1984. Forensic investigation of teeth marks in soap. British Dental Journal 157:270–271. 18. Whittaker, D. K. 1975. Some laboratory studies on the accuracy of bite mark comparison. International Dental Journal 25:166–171. 19. Rothwell, B. R., and A. V. Thien. 2001. Analysis of distortion in preserved bite mark skin. Journal of Forensic Sciences 46:573–576. 20. Avon, S. L. 2007. An in vivo model for the study of the accuracy of human bite mark analysis: Development of the system and testing the experts [dissertation]. Univ. of Toronto. 21. Dorion, R. B. J., M. J. Perron, S., and M. L. Nielsen. 2006. Bitemark research—Antemortem and postmortem bitemarks. American Academy of Forensic Sciences, Seattle, WA, Feb. 24, 2006. 22. Dorion, R. B. J., R. Beehler, T. Gromling, E. Meza, M. J. Perron, and S. Laforte. 2007. Bitemark research—Antemortem and postmortem bitemarks—Part 2. American Academy of Forensic Sciences, San Antonio, TX, Feb. 22, 2007.

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23. Dorion, R. B. J. 2007. Bitemark analysis—Part 1 and 2 results. American Academy of Forensic Sciences, San Antonio, TX, Feb. 22, 2007. 24. Dorion, R. B. J. 2010. Bite mark profiling based upon color, UV, and ALI photographic interpretation. American Academy of Forensic Sciences, Seattle, WA, Feb. 25, 2010. 25. Dorion, R. B. J., and M. J. Perron. 2010. Macroscopic and microscopic study of the effects of freezing and thawing on bite marks. American Academy of Forensic Sciences, Seattle, WA, Feb. 25, 2010. 26. Bush, M. A., R. G. Miller, P. J. Bush, and R. B. J. Dorion. 2009. Biomechanical factors in human dermal bitemarks in a cadaver model. Journal of Forensic Sciences 54:167–176. 27. Miller, R. G., P. J. Bush, R. B. J. Dorion, and M. A. Bush. 2009. Uniqueness of the dentition as impressed in human skin: A cadaver model. Journal of Forensic Sciences 54:909–914. 28. Bush, M. A., K. Thorsrud, R. G. Miller, R. B. J. Dorion, and P. J. Bush. 2010. The response of skin to applied stress: Investigation of bitemark distortion in a cadaver model. Journal of Forensic Sciences 55:71–75. 29. Harvey, W., P. Millington, J. C. Barbenel, and J. H. Evans. 1975. Experimental bite-marks. In Dental identification and forensic odontology, ed. W. Harvey, 124–135. London: Henry Kimpton. 30. Perron, M. J., and R. B. J. Dorion. 2010. Bite marks on a live victim: Data collection, healing process, and loss of details. American Academy of Forensic Sciences, Seattle, WA, Feb. 25, 2010. 31. Dailey, J. C., and C. M. Bowers. 1997. Aging of bitemarks: A literature review. Journal of Forensic Sciences 42:792–795. 32. West, M. H., R. E. Barsley, J. Frair, and M. D. Seal. 1990. The use of human skin in the fabrication of a bite mark template: Two case reports. Journal of Forensic Sciences 35:1477–1485. 33. Metcalf, R. D. 2008. Yet another method for marking incisal edges of teeth for bitemark analysis. Journal of Forensic Sciences 53:426–429. 34. Robinson, E., and J. Wentzel. 1992. Toneline bite mark photography. Journal of Forensic Sciences 37:195–207. 35. Ferrell, W. L., R. D. Rawson, R. S. Steffens, et al. 1987. Computerized axial tomography as an aid in bite mark analysis: A case report. Journal of Forensic Sciences 32:266–272. 36. Dailey, J. C. 1991. A practical technique for the fabrication of transparent bite mark overlays. Journal of Forensic Sciences 36:565–570. 37. Naru, A. S., and E. Dykes. 1996. The use of a digital imaging technique to aid bite mark analysis. Science & Justice 36:47–50. 38. Naru, A. S., and E. Dykes. 1997. Digital image cross-correlation technique for bite mark investigations. Science & Justice 37:251–258. 39. Sweet, D., M. Parhar and R. E. Wood. 1998. Computerbased production of bite mark comparison overlays. Journal of Forensic Sciences 43:1050–1055.

40. Pretty, I. A., and D. Sweet. 2001. Digital bite mark overlays—An analysis of effectiveness. Journal of Forensic Sciences 46:1385–1391. 41. Sweet, D., and C. M. Bowers. 1998. Accuracy of bite mark overlays: A comparison of five common methods to produce exemplars from a suspect’s dentition. Journal of Forensic Sciences 43:362–367. 42. Bowers, C. M., and R. J. Johansen. 2000. Digital analysis of bitemark evidence, 59–76. Santa Barbara, CA: Forensic Imaging Services. 43. Dailey, J. C. 2002. The topographic mapping of teeth for overlay production in bite mark analysis. Proceedings of the American Academy of Forensic Sciences, Atlanta, GA, 158–159. 44. Bernitz, H., J. H. Owen, W. F. P. Van Heerden, and T. Solheim. 2008. An integrated technique for the analysis of skin bite marks. Journal of Forensic Sciences 53:194–198. 45. O’Connor, T. R. http://faculty.ncwc.edu/toconnor/425/â•‰ 425lect16.htm 46. Bernitz, H., W. F. P. Van Heerden, T. Solheim, and J. H. Owen. 2006. A technique to capture, analyze, and quantify anterior teeth rotations for application in court cases involving tooth marks. Journal of Forensic Sciences 51:624–629. 47. Kieser, J. A., V. Bernal, J. N. Waddell, and S. Raju. 2007. The uniqueness of the human anterior dentition: A geometric morphometric analysis. Journal of Forensic Sciences 52:671–677. 48. Pretty, I. H., and M. D. Turnbull. 2001. Lack of uniqueness between two bite mark suspects. Journal of Forensic Sciences 46:1487–1491. 49. Van der Velden, A., M. Spiessens, and G. Willems. 2006. Bite mark analysis and comparison using image perception technology. Journal of Forensic Sciences 24:14–17. 50. Martin-de las Heras, S., A. Valenzuela, C. Ogayar, et al. 2005. Computer-based production of comparison overlays from 3D-scanned dental casts for bite mark analysis. Journal of Forensic Sciences 52:151–156. 51. Blackwell, S. A., R. V. Taylor, I. Gordon, et al. 2007. 3-D imaging and quantitative comparison of human dentition and simulated bite marks. International Journal of Legal Medicine 121:9–17. 52. Lasser, A. J., A. J. Warnick, and G. M. Berman. 2009. Three-dimensional comparative analysis of bitemarks. Journal of Forensic Sciences 54:658–651. 53. Martin-de las Heras, S., A. Valenzuela, A. J. ValVerde, et al. 2007. Effectiveness of comparison overlays generated with DentalPrint software in bite mark analysis. Journal of Forensic Sciences 52:151–156. 54. Martin-de las Heras, S., and D. Tafur. 2009. Comparison of simulated human dermal bitemarks possessing threedimensional attribute to suspected biters using a propriety three-dimensional comparison. Forensic Science International 190:33–37. 55. West, M. H., and J. Frair. 1989. The use of videotape to demonstrate the dynamics of bite marks. Journal of Forensic Sciences 34:88–95.

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56. Ripley, A. 2007. Can we spot the threat? Time 170(3): 59. Pretty, I. A., and D. Sweet. 2001. Digital bite mark over26–31. lays—An analysis of effectiveness. Journal of Forensic 57. Committee on Identifying the Needs of the Forensic Sciences 46:1385–1391. Sciences Community, National Research Council. 2009. 60. Arheart, K. L., and I. A. Pretty. 2001. Results of the Strengthening forensic science in the United States: A path 4th ABFO bitemark workshop, 1999. Forensic Science forward. Washington, D.C.: National Academies Press. International 124:104–111. 58. Whittaker, D. K., M. R. Brickley, and L. Evans. 1998. A 61. Harvey, W., P. Millington, J. C. Barbenel, et al. 1975. comparison of the ability of experts and nonexperts to Experimental bite-marks. In Dental identification differentiate between adult and child human bite marks and forensic odontology, ed. W. Harvey, 134. London: using receiver operating characteristics (ROC) analysis. Henry Kimpton. Forensic Science International 92:11–20.

The Reports

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Bitemark Report Mark L. Bernstein Contents 26.1 26.2 26.3 26.4

Goal of the Forensic Report Objectives of the Forensic Report Basic Qualities of the Forensic Report Bitemark Report 26.4.1 Preparation 26.4.2 Contents of a Bitemark Report 26.5 Data about the Victim 26.5.1 Demographics/History 26.5.2 Collection of Evidence 26.5.3 Analysis of Evidence 26.6 Data about the Suspect 26.6.1 Demographics/History 26.6.2 Collection of Evidence 26.7 Comparison 26.8 Conclusion 26.9 Disposition of Evidence 26.10 Investigator Information 26.11 Perspective 26.12 Security References

493 493 493 494 494 495 495 495 495 495 495 495 495 495 496 496 496 496 496 496

26.1â•…Goal of the Forensic Report The goal of any forensic report is to communicate the expert’s conclusion. For the conclusion to be valid, it must reflect an objective evaluation and interpretation of complete and accurate information.

26.2â•…Objectives of the Forensic Report As an accounting of a medicolegal investigation, the forensic report has three objectives: documentation, education, and communication. The report identifies the case, catalogs the evidence, and records the observations, studies, and results on which opinions are based. It lists the agencies and personnel who have supplied evidence or who are to be contacted by the author. The report also accounts for the disposition of evidence. As such, the report itself becomes evidence that can be scrutinized in court and for which the author is accountable. Additionally, the report serves to refresh the memory of the author, who might be summoned to defend opinions years after the report was completed. Forensic

reports are prepared by those with special knowledge in a particular aspect of a case. It is the author’s obligation to educate law enforcement and medical and legal personnel who rely on this information. The report must convey the specialist’s opinions in clear and simple language. The odontologist must be mindful that professional terminology is erudite and must be explained to nondentists.

26.3â•…Basic Qualities of the Forensic Report The style, length, and specific content of a report will vary with the author, the case, and the purpose for which the report is intended [1]. Regardless of these variables, all forensic reports must express valid conclusions. To this end, it is desirable that reports reflect four basic qualities that help safeguard validity: 1. The report should be complete in that it includes all relevant data, whether or not they support the investigator’s opinion. 2. The data must be accurate to the extent that they can be verified.

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Table 26.1 Measures to Maintain Objectivity 1. Following complete analysis of a bitemark, profile the biter’s dentition (if possible and with the precautions addressed in Chapter 6) in the report prior to examination of the suspect’s teeth. 2. Refrain from verbalizing conclusions based on early speculation and unsubstantiated preliminary opinions to investigators or news reporters until the report is written. 3. Evaluate suspect evidence in a blinded fashion (request supervised collection by another dentist, include nonsuspect controls, receive as coded unknowns). 4. Evaluate all suspects in a case (if possible). 5. Report any factors that complicate analysis. 6. Attribute statements made by others to their sources or as alleged facts rather than as uncontested facts. 7. List literature or references that were used to aid analysis. 8. Formulate conclusions independently of other influences, such as DNA analysis, statements, or reports made by others. 9. Before reporting a level of confidence in perpetrator identification, test the distinctiveness of the bitemark against other dentitions. 10. Obtain a second opinion if this is procedurally allowed by the soliciting agency.

3. Objectivity signifies that complete and accurate data have been evaluated in an unbiased manner with a commitment to the tenets of scientific methodology and professional ethics. Although objectivity is not necessarily expressed in a report, it is a contentious area in trials. When assurances of objectivity can be contained in forensic reports, the expert’s opinion is more credible. Table 26.1 lists examples of procedures that support objective analysis and can be embodied within the report. 4. The conclusions expressed in a report must be logically derived from the analysis. Their wording must be unambiguous, using prescribed terminology or explaining terms that could be misconstrued. Other qualities desirable in forensic reports include organization and proper use of language. Reports should be concise—not necessarily short, but rather prepared with economy of words. Finnegan advises that attorneys may request brief reports listing only demographic identifiers and the expert’s conclusions, omitting details and analysis. In this situation, the investigator should maintain complete notes and thorough analysis in anticipation of future testimony [1]. The report should be dated and signed and the author’s credentials attached unless precluded by security concerns, in which case a coding system can be used [2].

26.4 Bitemark Report The preceding text provided goals, objectives, and qual ities generally applicable to all forensic reports. The remainder of the chapter focuses on the specific construction of the bitemark report. 26.4.1 Preparation The final report can only be as complete and accurate as the investigation on which it is based. The typical bitemark case is an emergent situation requiring an immediate response. During the chaos, it is possible to overlook certain aspects of evidence collection. Experienced odontologists often prepare for such events by maintaining a standard protocol to help document and sequence evidence collection. In this way, a checklist of prescribed procedures prompts the investigator so that nothing is omitted. The American Board of Forensic Odontology (ABFO) provides bitemark methodology guidelines [3] to help the odontologist customize a worksheet that conforms to his or her practice. The bitemark report is finalized upon completion of the case, often months after it has begun. In order to guarantee a thorough and meticulous report, it is desirable to make notes as the case progresses. Observations and communications promptly recorded tend to be more accurate than recollections made afterward. As mentioned, reports may vary depending on the case. Table 26.2 illustrates some of the factors that may influence the organization or length of the report. In some cases, the odontologist may wish to make two separate reports: one issued to the agency that requested the examination and documentation of injuries and a second, issued sometime later, incorporating the details of the first report with the comparative studies and analysis made on suspect evidence.

Table 26.2 Factors That Influence Length and Style of the Bitemark Report 1. Living or deceased victim 2. Bitten individual—victim or crime suspect 3. Nature of patterned injury (adult, child, or animal bitemark or not identifiable as a bitemark) 4. Cutaneous bitemark or bitemark in substrate 5. Number of bitemarks 6. Number of suspects 7. Evidence collected by author or received from another source 8. Primary report or second opinion

Bitemark Report Table 26.3 Suggested Components of a Standard Bitemark Report 1. Injury data a. Chronology (demographics/history) b. Collection and description of injury evidence c. Evaluation of injury/evidentiary value 2. Suspect data a. Demographics/history b. Collection of evidence 3. Comparison a. Methods b. Results 4. Conclusion and its basis a. Analysis b. Opinion c. Scientific basis d. Critique of other expert opinions (if applicable) 5. Inventory and disposition of evidence 6. Name, title, and signature of odontologist, and date sent

495

and response of the odontologist: date and time contacted, by whom, nature of contact (phone, e-mail), and the requested task, as well as the arrival time of the odontologist or evidence brought to the odontologist, location, and parties present. 26.5.2 Collection of Evidence This includes any consent or court order (on living bitten persons) and the order and details of evidence collection. Initial photographs, swabs, sketches, narrative description of injuries, making of critical photographs, history of injury (on living patients), impressions, excision of injuries, and examination and impressions of victim’s dentition would be described and detailed in this section. In cases where the odontologist was not directly involved with evidence collection, the evidence should be inventoried and described.

26.4.2 Contents of a Bitemark Report

26.5.3 Analysis of Evidence

In his abstract presented at the American Academy of Forensic Sciences annual meeting in 2001, Finnegan listed elements to be included in a standard anthropological report. More recently, the Scientific Working Group on Materials Analysis has published guidelines for expert report writing intended primarily for crime laboratories [2]. In similar fashion, the ABFO has suggested guidelines for writing standard bitemark reports [4]. Additionally, the National Academy of Sciences issued a comprehensive review of forensic sciences in 2009. The report emphasizes the need for precise terminology to communicate opinions and inclusion of descriptions of methodology [5]. All these reports have been incorporated and modified for this chapter. Table 26.3 summarizes these recommendations, which are detailed in the following sections. As guidelines, they are comprehensive and cover most circumstances. All are not mandatory, and individual cases determine which of these components are applicable.

The odontologist determines the nature of the injury using established criteria and terminology, such as ABFO Bitemark Terminology Guidelines [6] and then indicates a level of confidence that the injury represents a bitemark. It may also be desirable to comment on quality of the bitemark and its anticipated value as evidence in the case.

26.5 Data about the Victim 26.5.1 Demographics/History This introduction serves to identify, catalog, and locate the case and to describe the odontologist’s initial involvement. It includes the full name of the injured person, including maiden name and aliases, date of birth, gender, race, and case number (medical examiner or coroner, police, court case, etc.). Also included is the notification

26.6 Data about the Suspect 26.6.1 Demographics/History This would include a synopsis of communications between the odontologist and legal authorities to direct collection of suspect evidence (informed consent, court order, appointment date to collect evidence, and instructions to others who might collect evidence). 26.6.2 Collection of Evidence Included here are the details of the oral examination, photographs, impressions and models, bite registrations, buccal swabs (if appropriate), and safeguards used to maintain objectivity.

26.7 Comparison This section lists the procedures used for comparison between bitemark and suspect teeth and records the results.

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26.8â•…Conclusion The results of comparative analysis are interpreted. Using ABFO Bitemark Terminology Guidelines [6], the forensic odontologist formulates a conclusion that accurately communicates the level of confidence regarding the origin of the bitemark and the scientific basis for the conclusion. If another odontologist’s report has been submitted as evidence, it should be critiqued.

26.9â•…Disposition of Evidence An inventory of all evidence and its disposition, along with chain-of-custody information, should accompany the report. The use of embedded and annotated images is easily accomplished with computer software programs, as suggested in ABFO forensic report writing guidelines [4]. Certainly, images are helpful in illustrating the descriptions and techniques used. However, if a written report is collected as trial evidence, it becomes public record, which can be problematic if it violates privacy laws. Some odontologists prefer to keep photographs and diagrams separate from formal reports.

26.10â•…Investigator Information Finally, the report should include the name, title, address, phone number, and signature or code of the odontologist and the date sent.

26.11â•…Perspective The odontologist must always assume that, as a potential expert witness, his or her techniques, findings, and opinions are going to be challenged. As a discoverable and unalterable expression of his or her work, the report becomes a target of the challenge. If a report reflects a valid opinion derived from reasonable analysis of accurate data, then the challenge will be footloose, based on irrelevant protests or, perhaps, a less competent analysis from an opposing expert. A challenge can also be based on perceived shortcomings in a report, such as errors, omissions, unsubstantiated conclusions, or overzealous opinions.

In order to construct a report that is essentially unassailable, the forensic odontologist should put it aside for a few days and then reexamine it with the perspective of an opposing expert or attorney. How might an attack be launched? What errors, such as incorrect tooth numbers or right or left orientation, were overlooked in proofreading? What could have been stated more accurately? What oversight can be exploited? What assurances of objectivity have been provided? What conclusion is vague in meaning, thus allowing a possible misinterpretation? What opinion is not worded in compliance with ABFO guidelines and thus can garner a challenge? Having addressed these considerations, the forensic odontologist can submit the report with confidence.

26.12â•…Security The only recipient of a bitemark report is the agent who requested the services of the odontologist or his or her designee. Reports should be posted, faxed, e-mailed, or delivered by hand to the intended recipient in a manner that will guarantee confidentiality (e.g., encrypted e-mail). Any other requests for a copy should have written approval of the primary solicitor or a court order.

References 1. Finnegan, M. 2001. What should be in a forensic anthropological report? Abstract H35. Proceedings of American Academy of Forensic Sciences, Annual Meeting, Feb. 19–24, 2001. 2. Scientific Working Group on Materials Analysis (SWGMAT). 2009. Expert reporting guidelines. Forensic Science Communications 11: 1. 3. American Board of Forensic Odontology. 1994. ABFO bitemark methodology guidelines. Colorado Springs, CO: ABFO. 4. American Board of Forensic Odontology. 1999. ABFO report writing guidelines. Colorado Springs, CO: ABFO. 5. National Research Council of the National Academies. 2009. Strengthening forensic sciences in the United States: A path forward. Washington, D.C.: National Academy Press (http://www.nap.edu/nap-cgi/report. cgi?record_id=12589&type=pdfxsum). 6. American Board of Forensic Odontology. 1995. ABFO bitemark terminology guidelines. Colorado Springs, CO: ABFO.

Prevention and Contamination

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Precautionary Measures Paul G. Stimson

Contents 27.1 Introduction 27.2 Personnel 27.3 In the Living 27.4 At Autopsy 27.5 Instruments and Equipment 27.6 Impressions and Casts References

499 499 500 500 501 501 503

27.1â•…Introduction

27.2â•…Personnel

This chapter proposes means and methods of protecting the forensic examiner/assistant from contamination or infection emanating from a living or deceased individual. Every examinee should be considered potentially chemically, virally, or bacterially contaminated or infectious, particularly since the era of terrorism. There is also the possibility of radioisotope contamination from the use of a “dirty bomb.” The simple act of photographing or recording a person’s or body’s condition can lead to contamination issues. Airborne pathogens such as anthrax or those causing severe acute respiratory syndrome (SARS) can be transferred from examinee to equipment and, ultimately, be inhaled or absorbed by third parties. Hepatitis B and C, human immunodeficiency virus (HIV), and other pathogenic diseases can be present with no obvious outward signs. Suggestions incorporating decontamination measÂ� ures for various tools and equipment required in forensic procedures are discussed in this chapter. Self-protection is a prime consideration in the examination. The ultimate goal is to obtain the necessary information, photographs, examination, specimen, etc., free of contamination and infection. Prevention of cross-contamination is another objective. In case of an exposure to nuclear materials from a dirty bomb, the site would have to be secured and the resultant casualties decontaminated prior to being brought to a morgue or a hospital. If the morgue is in the area of exposure or is heavily exposed to nuclear material, a temporary morgue would have to be set up in an uncontaminated area. Proper procedures for decontamination of facilities, personnel, and bodies must be in place and must be followed.

Strict personal sanitation habits must be observed by anyone dealing with a living or deceased individual. One problem quickly encountered is that of washing the hands. Rotter [1] has shown that the use of nonaqueous ethanol or propanols offers many advantages with either unmedicated or medicated soap in both hygienic and surgical hand disinfection: “Alcohols exert the strongest and fastest activity against a wide spectrum of bacteria and fungi (but not bacterial spores) as well as enveloped (but less so against non-enveloped) viruses, being little influenced by interfering substances.” In other words, self-protection can be achieved in any contamination situation by the use of alcohol-type hand-washing material. Alcohol materials are easily obtained and should be a part of the kit that a forensic individual carries. Alcoholbased antiseptic agents are available in gels, foams, or rinses that do not require the use of water. According to studies summarized in the present Centers for Disease Control and Prevention guideline [2], the waterless, alcohol-based products are more effective at reducing microbial flora on health care workers’ hands than a plain soap or antimicrobial hand wash. The use and method of application are simple and easy to accomplish when sinks may not be available. Nosocomial infections are a problem in intensive care units. One study showed a 30% increase in handwashing compliance using the alcohol-based hand rub [3]. The authors stated that the less time-consuming hand-rubbing might replace standard hand-washing and overcome the barrier of time constraints in intensive care units. This technique is ideal for the forensic scientist in a situation where hand-washing and hygiene have

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been compromised. When gloves are worn, hands can quickly be cleaned before and after use. Alcohol-based hand rubs can be used when gloves are punctured by a variety of sharp objects present in the environment, the equipment, or the oral cavity. Thicker gloves can be used to overcome this problem; however, there is a decrease in tactile sense. Alcohol-type hand-washing preparations should not be used on visibly soiled hands. These products cannot ever fully replace the need for sinks or other handwashing hygiene in a health care or forensic setting. Dispensing the proper amount of material is critical. After frequent use, drying occurs unless the formula contains emollients or other skin-conditioning materials. It is also important to realize that alcohol-based materials are flammable and must be stored away from high temperatures or flames. Soaps and alcohol preparations with additives (e.g., fragrance or preservatives) may cause allergic skin conditions. Allergies to natural rubber latex (NRL) affect between 8% and 25% of health care workers. Methods of treatment and prevention are covered in the article by Mills [4]. The use of protective clothing is a key element and essential to infection control and prevention. Anyone likely to be exposed to potential infection should approach each contact, living or deceased, as contaminated. The protective clothing must be accessible and worn prior to contact. Many items of protective clothing are incorporated within the concept of universal precautions—that is, those precautions necessary to reduce exposure to blood or body fluids [5]. Gowns, aprons, lab coats, clinic jackets, or similar outer garments, either reusable or disposable, must be worn when clothing or skin is likely to be exposed to blood or body fluids or contaminated materials. A forensic kit should be assembled and ready to use when needed. Many disposable products are available that can be safely and easily discarded. If biohazard bags are not provided, heavy plastic bags may be used for disposal of soiled materials and clothing. Clothing to be washed after removal must also be placed in heavy plastic bags [6].

27.3 In the Living When called to examine or perform a forensic procedure, the forensic examiner should obtain a clinical briefing of case and circumstance. The more questions the examiner asks, the better prepared he or she will be. Where will the examination be done? Under whose authority will it be done? Where is the written authorization, warrant, or court order? The full extent of the hazards present or

potentially present must be known before the examiner starts the work. Prevention is worth a pound of cure for the examiner and for those who assist him or her. Is the examined individual incarcerated, unconscious, etc.? A checklist will be helpful to ascertain answers to the preceding questions and other inquiries for a particular case. Caution is the advice for any practicing dentist who chooses to use his or her office for forensic work. An escorted AIDS-tubercular detainee in chains strolling through the office during normal business hours may not be appreciated. A forensic examination kit and protocol should be preassembled. The kit may contain equipment, instruments, impression trays, etc., specific to forensic examinations. The dentist must be prepared to answer questions that may be raised about his or her forensic endeavors. This makes good business, forensic, and preventive sense.

27.4 At Autopsy The same rules apply for the clinical briefing of case and circumstance prior to autopsy. Written authorization should always be obtained. Most medical examiner offices and hospital morgues have protocols that dictate the use of proper clothing, aprons, gloves, hair covering, masks, etc. Shoe coverings or separate forensic footwear (disposable or not) is highly recommended. Nolte, Taylor, and Richmond point out that an autopsy may subject prosectors and others forensic examiners to a wide variety of infectious agents [7]. These include blood-borne and aerosolized pathogens such as human immunodeficiency virus (HIV), hepatitis B and C viruses, and Mycobacterium tuberculosis. They also discuss other hazards, such as toxic chemicals (e.g., formalin, cyanide, and organophosphates) and radiation from radionuclides used for patient therapy and diagnosis. These risks will be reduced by proper assessment and appropriate autopsy procedures. Healing, Hoffman, and Young [8] point out that none of the organisms that caused mass death in the past—for example, plague, cholera, typhoid, tuberculosis, anthrax, and smallpox—is likely to survive long in buried human remains [9]. Items such as mold spores or lead dust are a much greater risk to those involved in exhumations. However, in the recently deceased, risks include tuberculosis, group A streptococcal infection, gastrointestinal organisms, the agents that cause transmissible spongiform encephalopathies (such as Creutzfeldt–Jakob disease), hepatitis B and C, viruses, HIV, and possibly meningitis and septicemia (especially meningococcal). It is readily apparent that the

Precautionary Measures

use of protective clothing and proper morgue protocol is imperative. In addition, individuals in the health and forensic related fields should have an immunization against hepatitis B. Other immunizations might prove beneficial, if not necessary, on the advice of an infectious disease specialist or family physician. When the examination and procedures are undertaken, protective clothing must be worn. Surgical masks or chin-length plastic face shields are recommended as well as protective eyewear with side shields. Hand- or alcohol-cleaner washing should be performed before gloving. When working and charting are done alone, double-gloving is recommended. The first pair of gloves is used for charting and the second is used for work on the deceased. The chance of cross-contamination is minimized. Surface disinfection can be accomplished with a bleach solution (dilution 1:100, bleach to water). This is extremely effective for most pathogens. Viruses and tuberculosis spores are killed by this solution in about 10 min. High-concentration alcohols (ethyl alcohol or isopropyl of at least 70%) can be used on precleaned surfaces. Any product that is routinely used in a dental office can also be used if the directions and procedures are properly followed. Clothing storage in a morgue situation presents many problems. If the contaminant on the clothing is a biological agent such as blood or sperm, the clothing can be dried with forced warm air. After drying, clothing can be sealed in plastic wrappings until needed. Gentle drying will preserve blood and sperm, and they can be rehydrated for further testing when needed. If other special tests such as those for volatile materials, smokeless gunpowder, or trace metals are required, the clothing will have to be processed in a special manner to preserve the element for the test. Some morgues have enough freezer capacity to store wet clothing until needed for testing. The inventory of materials stored must be closely monitored and these materials discarded when they are no longer needed for testing or other uses.

27.5â•…Instruments and Equipment All dental instruments should be cleaned (preferably by ultrasonic equipment) to remove adherent materials and organic debris, sterilized (autoclaved or rapid dry heat), and bagged. The bags should be dated as to procedures undergone and stored in a secure area. There are also some FDA-cleared immersion disinfectants and sterilants for instruments that cannot be autoclaved. Examples include all plastic instruments (cheek retractors, etc.) and instruments containing solder (impression trays, etc.). Organization for Safety and

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Asepsis Procedures (OSAP) [9] charts (TablesÂ€ 27.1 and 27.2) might assist in selecting the best surface and instrument immersion disinfectants for dentistry and forensics. On rare occasions, autopsy instruments are autoclaved when a highly contagious case has been done or is suspected. This procedure is undertaken to ensure that the instruments are clean and free of infectious agents because of their multiple uses in a morgue situation. Cameras should be kept in hand or placed in plastic bags or paper towels when in use in the morgue. In extremely hazardous and infectious situations, photographs can be taken with an underwater camera setup, and then the outer surface of the watertight camera case can be wiped with a bleach solution. The photographer should wear disposable gloves and discard them after the photography is completed. Alcohol wipes of 70% or more can be used on the outer surfaces of cameras, but this might affect the outer portions of the camera over time. Care should be taken with alcohol-type swabs near camera lenses because they can affect or remove ultraviolet and other lens coatings.

27.6â•…Impressions and Casts Bitemark and dental impressions must be disinfected. The American Dental Association (ADA) makes the following recommendations [10]: Immersion in disinfectants improves the wettability of polysulfide impression materials but the hydrophilic addition silicone impression materials are somewhat adversely affected by most disinfectants. Agar (alginates) impression materials should be immersed in hypochlorite, iodophor or glutaraldehyde with phenolic buffer. Stone casts may be immersed in iodophor or hypochlorite or alternatively spray disinfectants may be used. Zinc oxide eugenol impression materials may be disinfected by immersion in glutaraldehyde or iodophor. These impression materials are rarely used in a forensic setting, but can be used if nothing else is available or the usual materials used will not set under the situation being impressed. The use of ADA accepted disinfectants that require no more than 30 minutes for disinfection is preferred. As the impression material/ disinfectant compatibility may vary even within the same generic areas, the manufacturers’ recommendations for proper disinfection should be followed.

Polysulfides, silicones, and polyethers can be immersed in accepted products. Polysiloxane and the acrylic tray materials used for bitemark impressions can also be immersed in accepted products.

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Table 27.1 Environmental Protection Agency-Registered Surface Disinfectants for Forensic Dentistry Category/Active Ingredient

Contacta

Pros

Cons

Chlorines (sodium hypochlorite diluted in office, chlorine dioxide, commercial preparations of sodium hypochlorite with added surfactants) Complex phenols (“synthetic phenols” containing multiple phenolic agents)

2–10 min at 20 or 25°Cb

Economical; rapid; broad spectrum; tuberculocidal; effective in dilute solution

10 min at 20 or 25°Cb

Broad-spectrum activity; residual activity; effective cleaner and disinfectant; tuberculocidal; compatible with metal, glass, rubber, and plastic Broad-spectrum activity; tuberculocidal; hydrophilic virus claims; low toxicity; contains detergents for cleaning Broad-spectrum activity; tuberculocidal; relatively nontoxic; effective cleaner and disinfectant; residual biocidal action Tuberculocidal; fast acting; residual activity; some inhibit the growth of mold, mildew, and other fungi

Diluted solution must be prepared daily; cannot be reused; corrosive to some metals; may destroy fabrics; may irritate skin and other tissues; chlorine dioxide is a poor cleaner Extended exposure may degrade some plastics or leave etchings on glass; many preparations are limited to one day of use; may leave a residual film on treated surfaces Readily inactivated by anionic detergents and organic matter; can damage some materials

Dual/synergized quaternary ammonium compounds (alcohol and multiple quaternary ammonium compounds) Iodophors (iodine, combined with a surfactant)

6 or 10 min at 20°Cb

Phenol–alcohol combinations (phenolic agent in alcohol 10 min at 20 or 25°Cb base)

10 min at 20 or 25°Cb

Other halogens (sodium bromide and chloride)

5 min at 20°C

a b

10 min at 20°C

Fast acting; tuberculocidal; supplied in tablet form for simple dilution; requires minimal storage space

Unstable at higher temperatures; may discolor some surfaces; inactivated by alcohol and hard water; must be prepared daily; dilution and contact times are critical May cause porous surfaces to dry and crack; poor cleaning capabilities For use on hard surfaces only; chlorine smell

Contact time and temperatures for tuberculocidal activity. Varies by active ingredient or disinfectant brand.

Table 27.2 FDA-Approved Instrument Immersion Disinfectants for Forensic Dentistry Category/Active Ingredient Glutaraldehyde, 2.4–3.4% alkaline and acid formulations a

Hydrogen peroxide, 7.3% Ortho-pthalaldehyde, 0.55% Synergistic solutions 1.12% glutaraldehyde and 1.93% phenol/phenate 7.35% hydrogen peroxide and 0.23% peracetic acid

Classification

Contact Timing

Sterilant High-level disinfectant Sterilant High-level disinfectant High-level disinfectant

6–10 h at 20, 22, or 25°Ca 20–90 min at 20, 22, or 25°Ca 6 h at 20°C 30 min at 20°C 12 min at 20°C

Sterilant High-level disinfectant Sterilant High-level disinfectant

12 h at 25°C 20 min at 25°C 3 h at 20°C 15 min at 20°C

Note: Glutaraldehyde and simple quaternary ammonium should not be used for surface disinfection in dentistry or forensics. High-concentration alcohols (ethyl alcohol or isopropyl alcohol of at least 70%) should be used on precleaned surfaces. a Varies by active ingredient or disinfectant brand.

Precautionary Measures

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References 1. Rotter, M. L. 2001. Arguments for alcoholic hand disinfection. Journal of Hospital Infection 48 (Suppl A): S4–S8. 2. Centers for Disease Control and Prevention. 2002. Guidelines for hand hygiene in healthcare settings. Morbidity and Mortality Weekly Report 51 (RR16): 1–44. 3. Hugonnet, S., T. V. Perneger, and D. Pitter. 2002. Alcoholbased handrub improves compliance with hand hygiene in intensive care units. Archives of Internal Medicine 162:1037–1043. 4. Mills, C. 2002. Combating latex allergies. Infection Control Today 66:1. 5. Centers for Disease Control and Prevention. 1988. Perspectives in disease and health promotion update:

Precautions for prevention of transmission of human immunodeficiency virus, Hepatitis B virus, and other bloodborne pathogens in healthcare settings. Morbidity and Mortality Weekly Report 37 (24): 377–388. 6. York, V. 2002. Using protective clothing. Nursing Times 98:52. 7. Nolte, K. B., D. G. Taylor, and J. Y. Richmond. 2002. Biosafety considerations for autopsy. American Journal of Forensic Medicine and Pathology 23:107–122. 8. Healing, T. D., P. N. Hoffman, and S. E. Young. 1995. The infection hazards of human cadavers. Communicable Disease Report CDR Review 5:R61–R68. 9. OSAP chart and checklist. 2002. Infection control in practice. Medical Pathology 23:107–122. 10. Fan, P. L. 1991. Disinfection of impressions. Journal of American Dental Association 122:110.

Legal Considerations and the Courtroom

XI

28

Science and the Law Richard A. Mincer Harry H. Mincer Contents

28.1 Introduction 28.2 Why Do Almost Half of All Experts Get It Wrong? 28.3 The Legal System 28.3.1 Purpose: A Search for the Truth versus the Administration of Justice 28.3.2 Justice versus Truth 28.3.3 The Adversarial System 28.3.4 Evidentiary Restrictions 28.4 Science: Good versus Junk and Everything in Between 28.4.1 The Scientific Method 28.4.2 The Importance of Testing 28.4.3 The Importance of Objectivity 28.5 Interplay and Tension between Science and Advocacy 28.5.1 Different Rules for Different Roles 28.5.2 Choosing Sides 28.5.3 The Court-Appointed Expert: A Solution to All the Problems? 28.5.4 What Do Lawyers and Their Clients Really Want—“Hired Guns” or “Straight Shooters”? 28.6 Effective Presentation versus Factual Advocacy 28.7 How to Approach Serving as an Expert Witness in a Bitemark Case References

28.1â•…Introduction The issue raised by the National Academy of Sciences’ 2009 report [1] that bitemark evidence and other forms of pattern evidence have not been demonstrated to be scientifically reliable is discussed in depth elsewhere in this book. The present chapter points out what has long been the case: that our system of justice holds that, despite the fact that such evidence does not fall completely within the realm of “pure” science, if it is properly managed, it is a valuable tool toward arriving at judicial “truth.” The purpose of this chapter is to discuss the appropriate role of the forensic dentist as an expert witness in bitemark cases until such time as the courts rule that this form of evidence is inadmissible as a source of information for juries and other legal triers of fact.

28.2â•…Why Do Almost Half of All Experts Get It Wrong? According to news reports by the popular media, almost every high-profile courtroom litigation features a parade of key expert witnesses (including forensic odontologists

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in bitemark cases) who give diametrically opposite opinions. This would indicate that as many as 50% of all scientific opinions offered under oath during legal proceedings are just plain wrong. How is this possible? How can half of the trained and educated scientific experts, utilizing nearly identical methodology derived from the same body of scientific knowledge and analyzing exactly the same data, get it wrong at such an alarming rate? Certainly, if the New England Journal of Medicine had such a dismal track record, there would be wholesale changes in the editorial staff, cries of fraud, and a mass exodus of those who provide financial support to that esteemed publication. One would certainly question the integrity of the contributors and carefully scrutinize both their methodology and their objectivity, not to mention their ability to interpret the data honestly. The answer to this conundrum may lie in the inherent conflict between true science and a justice system that encourages advocacy to resolve adversarial proceedings. When the scientist turns advocate, objectivity and scientific reliability are often the victims. On the one hand, the expert should utilize effective and persuasive communication skills to help the jury understand the testimony. On the other hand, the expert should not

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attempt to manipulate the outcome of testing to support a given position. There is a very real difference between effectively communicating the results of an objective and unbiased review of the evidence and tailoring the testing and methodology to achieve a specific result. The question is whether the rules of the game are different when offering an expert legal opinion as opposed to publishing a conclusion for the scientific community. Should expert witnesses not employ the same level of intellectual rigor in the courtroom that they employ when they present a paper to their peers or submit an article to a peer-reviewed publication? This chapter discusses the interplay (or is it tension?) between science and the law with respect to scientific expert testimony. The following is neither a cookbook to advise experts how to persuade jurors nor a recitation of the relative merits or drawbacks of Daubert [2], Mohan [3], and similar precedent cases. Rather, the purpose of this chapter is to explore a possible explanation for the divergence of expert opinions in legal proceedings and to analyze how experts who cross the line between science and advocacy affect the administration of justice. What role does scientific evidence have in this process that ultimately intends to search for the truth? How does science affect the judicial system? More specifically, what is the proper role of the expert witness offering scientific opinions in a judicial proceeding?

28.3 The Legal System 28.3.1 Purpose: A Search for the Truth versus the Administration of Justice The legal system in civilized countries was designed to settle disputes and is premised, at least ostensibly, on a search for the truth. Whether the dispute is criminal or civil, the legal system is only triggered when the litigants cannot agree among themselves on a just outcome—in other words, cannot agree as to the definition of a just result. The basic operation of the legal system involves a trier of fact—a judge or a jury—who serves as the ultimate arbiter of factual disputes. The judge also makes threshold determinations regarding the admissibility of evidence based on established rules. These evidentiary rules are generally designed to ensure that the jury only considers reliable evidence. The legal reliability of evidence is typically based on the nature of the evidence, rather than on the content of the evidence, but there are exceptions. Hearsay evidence is a good example of the possible complexity confronting the judge when deciding admissibility. Hearsay is generally thought to be unreliable evidence. Anyone can say anything and, later, that

statement may be reported by someone else; therefore, the basic problem with hearsay is that the jury cannot assess the accuracy of the core statement. When B reports what he was told by A, his recall of the statement may be flawless. The question is not B’s memory of the conversation, but whether A’s statement was accurate in the first place; if A is not present at the proceedings, this cannot ordinarily be ascertained by the trier of fact. Sometimes, however, hearsay may be judged admissible by virtue of the context in which the statement was made or by the content of the statement. If, for example, the statement is made while observing an event and describes the event, it is more likely to be judged reliable and therefore admissible than a description of the same event made after some time has passed. Similarly, a statement against the declarant’s personal interest may also be considered reliable because people do not normally make statements that can get them into trouble. Thus, if a hearsay statement contains certain recognized indicia of reliability, it may be admitted into evidence, although the jury will ultimately determine whether the statement is true or false. In addition to admissibility, the judge also determines the law applicable to the facts and, as trier of fact, instructs the jury on it. Application of the law to the facts yields a result—in criminal cases, a determination of guilt or innocence and, in civil cases, whether one party is liable to another for damages. If the process works, justice is done; if the process fails, the result is unjust. Obviously, just results promote public confidence in the system. Confidence in and respect for the judicial system constitute a bedrock of a civilized society. Should the expert witness concern himself with whether or not the justice system works and, if so, to what extent? 28.3.2 Justice versus Truth Justice is defined as “moral rightness, equity, fairness, or honor” or “the proper administration of laws” that will “render every man his due.” Truth, on the other hand, is defined as “reality, actuality or conformity to knowledge, fact, actuality or logic.” The question becomes whether there can be a “just” result in any given case based on something other than “truth.” In practice, justice and the truth are not always the same. The legal system acknowledges, at least in a sense, that the two may diverge. While finding the truth is certainly a goal of the administration of justice, a “just” result is considered to have been achieved by giving a litigant a fair trial. If a dispute is tried before an impartial tribunal and the litigant has the opportunity to present evidence in his favor and to confront contrary evidence, then the

Science and the Law

result is looked upon as “just,” even if it is flatly contrary to factual truth. Despite this, many scholars have agreed that trial by jury may not be perfect (i.e., it may not always find the truth), but it is deemed better than alternative systems used in other parts of the world. Other aspects of the difference between truth and justice seem to be heavily dependent on individual points of view. In the civil arena, for example, many plaintiffs’ lawyers believe justice is achieved by fully compensating an injured victim, regardless of whether the party held liable is actually to blame for the injuries. If the person truly at fault is absent or, more importantly, incapable of paying a judgment, any available pocket will do as long as the victim and the attorney are compensated. Hence, the “deep-pockets syndrome” maintains its attractiveness to certain litigants and, unfortunately, to certain judges and jurors. Similarly, in criminal cases, some members of society believe that it may be just to convict the habitual but as yet unpunished criminal wrongfully for a particular crime. Since he has committed other crimes for which he has never been punished, in many people’s minds it is not a travesty to convict him for a crime he did not commit since he still deserves punishment for something. Of course, this leaves the subject crime unsolved, thereby depriving the victim of justice. Again, should expert witnesses concern themselves with whether the justice system works and, if so, to what extent? Should experts seek impartial truth or should they tailor their testimony to support the position of the attorney? More pointedly, should an expert fabricate testimony that might help convict an innocent person or free a guilty criminal? What could possibly motivate an expert to aid and abet such an unjust result? 28.3.3 The Adversarial System One explanation for an expert’s motivation to further this apparently unseemly cause lies in the fact that attorneys who retain experts are advocates. As an advocate, an attorney is only concerned with representing the best interests of his or her client as long as the claim or defense is cognizable under the law and has some basis in fact. In civil cases, this duty to zealously represent the interests of the client is relatively uncomplicated. In criminal cases, however, many defense attorneys do not want to know whether or not their client committed the crime. Rather, the focus is to present the best defense available under the law. In other words, the criminal defense attorney must do everything reasonably possible to see that the client gets his or her day in court and has a fair trial. Again, the attorney’s

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duty to advocate the position of the client is fairly clearcut. After all, an acquittal certainly serves the best interest of the client, even if the client is truly guilty. Prosecutors, on the other hand, would seem to have a need to be more concerned with truth. Prosecutors serve the public—that is, all the citizens in the prosecutor’s jurisdiction. The citizens are interested in seeing perpetrators of crime punished for their wrongs. Citizens, as “clients” of prosecutors, lose when the result at trial does not reflect the truth. Certainly, citizens lose when a guilty person is acquitted. Similarly, citizens’ interests are not served when the prosecutor wins a conviction only to jail an honest person. After all, the real perpetrator, who presumably poses a threat to strike again, is still at large despite the prosecutor’s apparent victory at trial. The ideal role of the expert witness is to provide the attorney advice regarding the merits of the case and, ultimately, to help advance the client’s cause before a jury through the explanation of scientific or other technical evidence that may not otherwise be understood. A responsible attorney should seek a candid, unbiased opinion from the expert to assist with evaluation of the case. If the client’s case is weak, the attorney should seek early resolution of the case through settlement or a plea agreement. Early negotiations, if successful, will ameliorate or avoid risk and uncertainty, not to mention the time and expense of trial. Presumably, such tactics benefit the client who otherwise is unlikely to prevail at trial. By definition, compromise is never a complete victory or a total loss. Too often, however, the attorney is only interested in advocating the position of the client and has already evaluated the case before he retains an expert witness. Such an attorney is only interested in an expert who will further the preconceived “cause” of his client. Most attorneys believe that one can find an expert witness to support any position, regardless of how apparently untenable that position may be. Especially in cases in which the facts indicate a close call on the evidence, the attorney’s zeal to advocate his client’s position may infect the retained expert. When this occurs, the expert embarks on a course designed to prove a desired result rather than to provide an unbiased opinion based on objective testing. Worse, the expert may attempt to offer an opinion without doing the investigative work necessary to support that opinion. As one U.S. court remarked about an overzealous expert [4]: [The expert’s] affidavit exemplifies everything that is bad about expert witnesses in litigation. It is full of vigorous assertion (much of it legal analysis in the guise of expertise), carefully tailored to support plaintiffs’ position but devoid of analysis. [The expert] must have

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allowed the lawyers to write an affidavit in his name. … An expert who supplies nothing but a bottom line supplies nothing of value to the judicial process.

Many if not most experts, of course, refuse to be so swayed toward advocacy. The conscientious expert will provide an honest and objective evaluation of the issue at hand, regardless of whether the attorney actively seeks such candor. The desirable expert, at least from a responsible lawyer’s perspective, will then effectively and, yes, persuasively communicate this opinion to the jury. Unfortunately, communication skills, rather than scientifically valid results, often carry the day with the jury. 28.3.4 Evidentiary Restrictions It is important for the expert witness to remember that the threshold ruling on admissibility does not equate to a determination of whether or not the ultimate opinion reflects the truth. Judges merely decide whether the methodology or process utilized by the expert witness to reach a conclusion reflects a reasonable and responsible evaluation of the evidence. Therefore, the key to admissibility is really the same as the key to a valid and reliable opinion—namely, to employ objective and unbiased methodology to analyze all of the relevant evidence and, of equal importance, to consider and analyze contrary theories that, if proven, will effectively thwart the pos ition of the party retaining the expert. Proving a given theory while simultaneously disproving all contrary theories is powerful and persuasive evidence.

28.4 Science: Good versus Junk and Everything in Between 28.4.1 The Scientific Method Courts have recently encouraged use of the scientific method as a prerequisite to the admissibility of scientific expert testimony. The scientific method encompasses the formulation of a theory followed by rigorous testing to confirm or to disprove the theory. Numerous texts address this basic philosophy of science, so the relative merits of these arguments will not be addressed in detail here. Rather, we will point out that reliable scientific testimony entails something more than offering an opinion carefully tailored to advocate a given position, but completely devoid of analysis. The theory and the testing should be broad enough to include opposing and contrary theories.

It is important that the expert’s opinion and testimony emanate from objective testing, as opposed to the expert simply reviewing the facts of the case and the position of the advocate, and then attempting to work backward to manipulate the testing or otherwise craft methodology designed to explain a preconceived opinion solely for the purpose of supporting the retaining party. Moreover, if the testing negates the contrary opinion of the opposing expert, as well as confirming the result, the ultimate conclusion, from both scientific and legal standpoints, will be all the more reliable and persuasive. 28.4.2 The Importance of Testing From a legal standpoint, the hallmark of good science is objective testing. Such testing will generally utilize an accepted methodology that faithfully analyzes all the relevant facts of that specific case. Testing that employs questionable methodology or ignores salient facts is the easiest for a judge to rule inadmissible, regardless of the validity of the outcome. If the original testing was performed for scientific rather than legal purposes (in other words, was initially developed for use outside the courtroom), it is all the more persuasive with the trial judge. Typically, the expert should address the viability of the opinion in both general and specific terms. Most expert testimony deals with the validity of a cause-and-effect relationship between a set of circumstances and a known condition (did the occurrence of A result in B?) The facts that comprise A are usually known, as is the result defined as B. The typical question for the scientist is whether or not there is a causal relationship between the two. This analysis usually requires a two-step inquiry: first, could the occurrence of A ever have caused the occurrence of B and, second, did it actually occur in this specific case? Testing designed to address both general and specific causation should yield the more reliable and persuasive result. In bitemark analysis, the scientific question is simple. Was the condition B (the injury) a result of A (a human bite) (general) caused by the teeth of the suspect (specific)? The most widely accepted testing methodology for the analysis of bitemark evidence is detailed in the guidelines of the American Board of Forensic Odontology. 28.4.3 The Importance of Objectivity Good science demands objectivity. The scientific method is premised on objective testing and assumes that the scientist is searching for the truth, whatever form the truth may take. From both a scientific and a legal standpoint,

Science and the Law

the objective expert fulfills the role that expert witnesses are expected to play in the search for the truth. The legal system permits expert witnesses to offer opinions on the ultimate issue of fact precisely because the expert is presumed to be objective. After all, the very reason that experts are allowed to testify is to help the jury understand the evidence based on the expert’s specialized knowledge and training. Expert testimony is very powerful. Jurors are apt to cede their fact-finding mission to experts since the nature of the testimony is beyond the ken of the average juror. For this reason, judges act as gatekeepers whose function is to admit testimony that meets certain indicia of reliability while excluding that which is based on an incomplete review of the facts or is the product of unreliable or biased methodology. When it is apparent that an expert is merely saying whatever is necessary to support a party’s position at trial, that testimony is usually excluded, provided the opposing party is able to point out such shortcomings. Judges and juries can usually smell a hired gun. In fact, it is probably fair to say that most judges and many juries expect the retained expert to be a hired gun and begin their review of expert testimony with a certain amount of distrust. The quickest and easiest way to dispel these preconceived notions is to show that the testing, methodology, and, ultimately, the testimony at trial emerged from objectivity and impartiality. This bespeaks the professional integrity of the expert and fosters respect and trust from the jury. Thus, in addition to the other positive properties of objectivity, it is a very powerful tool for persuasion.

28.5 Interplay and Tension between Science and Advocacy 28.5.1 Different Rules for Different Roles It should be apparent from the foregoing that lawyers and expert witnesses play by different rules as they serve different roles in the administration of justice. Yet, in practice, lawyers and experts often do not appreciate or adhere to this distinction. This often leads to both overstepping their respective ethical bounds. Interestingly, each aids and abets the other’s unethical behavior. Lawyers are expected to represent the interests of their clients zealously. However, this responsibility is tempered by the duty to act as a responsible officer of the court, as well as the lawyer’s self-interest to earn a satisfactory living while remaining an upright person [5]. In essence, a lawyer as an advocate “has a duty to use legal procedure for the fullest benefit of the client’s cause,

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but also a duty not to abuse the legal procedure” [6]. In that regard, a lawyer may not “make a false statement of material fact or law to a tribunal … or offer evidence that the lawyer knows to be false” [7]. Furthermore, the lawyer may not counsel a person to falsify evidence or otherwise testify falsely [8]. The function of the expert is to address subject matter that is typically outside the lawyer’s scope of knowledge. Therefore, the lawyer relies on the expert to interpret the evidence within the pertinent field, to advise as to how the evidence will influence the outcome of the case, and to present and explain the evidence to the trier of fact at trial. However, an expert’s role in the case ends when the evidence is received, while the lawyer must then argue to the jury how they should interpret the evidence and how an application of pertinent law to the facts of the case should result in a verdict in favor of the client. Remember that ascertaining the facts of a given situation is only the first task faced by a jury. Once the facts are determined, the jury must then apply the relevant law as provided by the judge to determine whether a party is guilty, negligent, reckless, or otherwise culpable. After that determination is made, the jury or the judge must then impose a sentence or determine a fair award of damages. Too often, the lawyer does not communicate to the expert the distinction between their roles. Perhaps the lawyer assumes the expert knows the difference or perhaps the lawyer would rather not know. On the other hand, the expert may not appreciate his duty to provide an honest evaluation of the evidence and may believe that his job is to do whatever is necessary to support the lawyer’s and hence the client’s ultimate position in the litigation. In any event, expert witnesses and lawyers alike have a duty to present truthful evidence. In this respect, the relative duties correspond. Neither has a license to present false testimony or even to argue for the adoption of unreasonable inferences from the evidence; certainly, neither is capable of changing the facts of a given case. Unfortunately, some lawyers cross the line between providing an interpretation of the evidence and attempting to change facts. But, in fairness, sometimes the line between advocating reasonable inferences or deductions to be made from the facts and manufacturing evidence out of whole cloth is amazingly murky. After all, the end result of expert testimony is often “to provide the judge and jury with a ready-made inference which the judge and jury, due to the technical nature of the facts, are unable to formulate” [8]. Everyone knows that it is a crime knowingly to testify falsely under oath. Why then do we have so many

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cases with two opposing experts in which one or the other is, by definition, providing false testimony? Is it really possible that neither knows or at least strongly suspects that his or her testimony is patently false? How can this be? Perhaps the explanation for this is ignorance of the proper role for experts and confusion between a lawyer’s duty to advocate for his client and the expert’s duty to provide truthful testimony. The result-oriented expert may manipulate the data and/or the testing to achieve a desired result by ignoring certain unsupportive facts or by tailoring the testing or other methodology to yield a given result. In either event, the testing may be valid as far as it goes but not reflect the facts of the specific case. To put it another way, the ultimate result exemplifies the old adage: “Garbage in, garbage out.” When either the data or the methodology is inaccurate or suspect, the ultimate opinion of the expert suffers from the same shortcomings. The expert has therefore failed in his mission to help the jury understand the evidence since the true evidence is not reflected in the expert’s opinion or testimony. 28.5.2 Choosing Sides Why would an expert brush aside the product of his training, education, and experience to work backward from a conclusion rather than following the scientific method in which the testing defines the outcome? More importantly, why would an expert, with no stake in the outcome of the litigation, ever gamble with the possibility that an innocent person might be convicted, a criminal might be freed, or assets in a civil litigation might be unjustly reallocated? One apparent but decidedly jaded explanation is money. While many experts disdain any involvement in the legal process, many will participate provided the hourly rate of compensation is much higher than that received for typical work within their field. The expert who builds a reputation of “loyalty” to whoever is paying his fees will initially find more work as an expert, but only until this willingness to keep the payor happy backfires in front of a judge and jury and his game is exposed. Nevertheless, it cannot be disputed that monetary gain can certainly have an adverse effect on a person’s objectivity. Competitiveness and a desire to win may be another explanation for a loss of objectivity. Less experienced experts, particularly, seem to show a tendency to overstate the value of evidence that they have examined, possibly to enhance their reputations. Additionally, preconceived notions of right and wrong may affect the expert’s objectivity. For example,

personal views regarding the scope of corporate responsibility may entice an expert witness to slant his assessment of a toxic tort case if he would personally impose duty of care on corporate defendants that is higher than that imposed by law. Similarly, some experts may not be able to stomach testifying in support of a criminal suspect who is a scoundrel, while losing no sleep over the prospect of jailing this scoundrel for a crime he did not commit. More commonly, an expert for the prosecution may be biased toward believing that a defendant is probably guilty just because he is in custody, despite the fact that the evidence does little to support this belief. In this instance, the expert must be careful not to stretch the importance of the evidence toward the cause of the prosecution. Perhaps there are other explanations, but none would suffice to justify an expert’s attempt to mislead the judge and the jury in a process that will have very real implications for the litigants. 28.5.3 The Court-Appointed Expert: A Solution to All the Problems? If lawyers blur the lines or even encourage an expert to ignore the need for objectivity, or if experts are easily led astray by lawyers or by extraneous incentives, why not have the court retain a neutral expert or even impanel a collection of experts to render a final and unbiased opinion on matters outside the understanding of the court, the jury, and the attorneys? Would not the strict use of court-appointed experts alleviate the need for the judge to make threshold determinations on the admissibility of expert testimony—an exercise that nonscientists are certainly ill equipped to make in the first place? This would also alleviate the need for lay jurors to decide which of two competing experts has provided the more scientifically valid assessment of a set of facts that they, too, are simply unqualified to assess. Judges certainly have the ability and the procedural mechanisms at their disposal to retain court-appointed experts. Why not take this a step further and substitute a jury of experts for a lay jury to decide cases where a thorough understanding of a technical topic is central to the case? Undoubtedly, the use of experts in such a manner will often yield results that more closely reflect the truth than would a verdict rendered by lay jurors. This idea is not without ardent supporters. While we will not attempt to treat this complex topic here, suffice it to say that such mechanisms will face an uphill battle to gain widespread support. Certainly, in the United States, trial by jury is cherished as a unique and vital characteristic of the legal system. Many citizens, not just lawyers,

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espouse the belief that while the system is far from perfect, it is better than any alternative. Litigants take comfort in knowing that their dispute will be resolved by a jury of their peers (i.e., a jury of folks just like them), even if the system is imperfect. Along these lines, the American Board of Forensic Odontology, in an attempt to alleviate expert bias in bitemark cases, has adopted a guideline that recommends that, after interpretation by one expert, bitemark evidence should be reviewed independently by a second board-certified odontologist who has no direct interest in the case. Needless to say, this practice has not received universal acceptance among odontologists, attorneys, or the courts.

has properly advised them as to the weaknesses of the client’s position. Nevertheless, these illustrations should reveal that the best course of action when serving as an expert witness is to act as a straight shooter rather than a hired gun. Recognizing that your case is weak or even hopeless may be tough medicine to swallow, but it is usually preferable to learning this fact months or years and thousands of dollars later from a jury. Over time, an expert with a reputation as a straight shooter will not only find repeat business, but will also facilitate early resolution of claims because the opposing party will know that the expert’s opinions are accurate and will convince juries.

28.5.4 What Do Lawyers and Their Clients Really Want—“Hired Guns” or “Straight Shooters”?

28.6 Effective Presentation versus Factual Advocacy

Believe it or not, most lawyers and, more particularly, their clients really want an honest, objective evaluation of the issues presented to the expert for review. Sometimes this may not be readily apparent, but both are best served by hearing the good news and the bad from the retained expert. Some lawyers may fail to convey this principle clearly when discussing the case with experts, but a review of the consequences of a slanted, biased report reveals otherwise. When an expert has decided that the position of his side, be it defendant, plaintiff, or prosecution, has significant weaknesses, he must reveal these to the attorney, who will then make the decision whether compromise is appropriate. The opportunity to resolve an untenable case, either civil or criminal, by pretrial settlement will usually save everyone concerned immeasurable time, expense, and discomfort. When a client has lost the opportunity to compromise, he faces whatever the ultimate downside was of losing at trial and, in a civil case, must pay the taxable costs of the other side. In a criminal case (as virtually all bitemark cases are), the prosecution may lose an otherwise winnable case at taxpayers’ expense or the defendant may face a stiff sentence—both of which could have been ameliorated through a pretrial plea agreement. On top of all this, the parties now may face the added expense of an appeal because good science was lacking. Also, it is no longer rare for clients or their attorneys then to make claims against experts, spawning even more litigation. This is not to suggest that bad expert advice is the only reason clients find themselves in such predicaments. Clients and their attorneys make the same bad decisions for a number of reasons, even when an expert

As noted earlier, sometimes experts confuse the distinction between an effective presentation of their testimony and advocating for a specific result. While there is, arguably, some overlap, expert witnesses must appreciate and adhere to the distinction. There is, after all, a difference between an advocate and a scientist. Lawyers are advocates; the scientist must remain a scientist, despite being hired by an advocate. The expert’s objectivity and professionalism greatly enhance the advocate’s ability to argue the case and persuade the jury. This is not to suggest that expert witnesses should ignore the importance of an effective presentation. A witness faithfully serves the role of expert if he or she succeeds in teaching the subject matter to the jury so that, at the end of the testimony, they have gained at least a working understanding of the evidence. To achieve this, objectivity, professionalism, and an unbiased approach are powerful tools for gaining the jury’s trust. Also, the jury must trust the messenger or they will likely ignore the message. Similarly, organization, thoroughness, visual aids, and effective communication skills all assist to convey the message. Numerous texts and articles provide suggestions about how best to convey the message. Read these articles. If the jury falls asleep or is incapable of following your testimony because you talk over their heads, your message will be lost. Understand, however, that the message should simply be an explanation of the evidence—nothing more, nothing less. The message is not necessarily that the jury should find for the party retaining the expert, although the two are often inextricably intertwined. Regardless, the expert witness should not have an interest in the outcome and should present

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the evidence in a straightforward and objective manner. Leave the arguing to the attorneys.

28.7 How to Approach Serving as an Expert Witness in a Bitemark Case Bitemark evidence is often very important, sometimes vital, in the administration of justice. Incidents in which one human bites another are frequently parts of violent criminal activity, often homicides, and therefore often result in capital cases or litigation potentially resulting in long prison sentences. Such cases in most American jurisdictions are considered important enough to merit jury trials. However, in most instances, the issues are straightforward. Is the skin injury in question the result of a human bite? Was it caused by the teeth of the defendant? Of course, there are other technical considerations, as outlined elsewhere in this text, such as clarity of the bitemark, uniqueness of the purported biter’s teeth, degree of certainty, an open versus a closed population of suspects (exclusive opportunity), etc. The following are suggestions for serving as an expert witness in a bitemark case based on the preceding discussion: • As soon as possible after receiving the evidence, give a completely honest appraisal of it to the attorney. Stress the weaknesses and potential downside rather than bolstering the upside. It is best that the attorney knows the case’s weaknesses from the start. • Understand your role and your limitations. Disclose and discuss these limitations with counsel and make sure your role is clearly defined. Also, discuss any budget considerations with counsel at the beginning of the relationship. Be certain that you understand any admissibility thresholds in the relevant jurisdiction, discuss these with counsel, and make sure your work on the case satisfies these requirements. • Examine everything available to counsel that could bear on your interpretation of the bitemark evidence, and request additional materials as needed. For example, you should read the opposing experts’ reports and depositions, carefully look at all crime scene photographs and reports, and examine the medical examiner’s documentation, injury orientation photographs, and diagrams. These can provide valuable information for your analysis, such as answers to the following questions:

•

•

•

•

•

• Was the bitemark inflicted through clothing, explaining its lack of clarity? • Was the wound distorted by body position? • What was the position of the biter in relation to the victim? • What was the estimated timing of the bite injury as related to death? Remember, however, that your expertise deals only with physical evidence. You do not need to know the criminal record of the suspect, the relationship between the suspect and the victim, or other information that might bias your interpretation. In fact, some authorities go so far as to recommend that to prevent this type of bias, an expert should not meet the suspect until the trial. This would necessitate that another individual gather evidence from the suspect (dental measurements, oral photographs, dental impressions, etc.). Research the field. Be totally familiar with the published bitemark literature. Know what others have done before you, particularly when the research was performed for pure scientific purposes as opposed to litigation. Educate the attorney about the science of bitemark analysis. Most importantly, know what you have said or published on this topic prior to this litigation. Be prepared to address contrary opinions of others or those previously given by you. Carefully organize and maintain a detailed file in a way that will facilitate its use throughout your work on the case, including depositions and trial. Record the date and time for every activity that you perform in your analysis. Remember that the trial will probably be delayed for several months after your investigation and you may not remember all the details without adequate notes. Formulate theories, testing, and methodology designed to find the objective truth. Make sure you understand the contrary theories that may be presented by the opposing party. Incorporate these into your testing and final opinions. Rigorously test your hypotheses as if you were going to publish the results in a respected, peer-reviewed journal. Do not cut corners and refrain from the impulse to slant either the data or the methodology. Meticulously document your testing and the results. It is very damaging to the case to forget why you performed a specific test or, even worse, to forget the results. It is also very unprofessional, not to mention personally embarrassing.

Science and the Law

• Provide a formal report as described elsewhere in this text. Include the purpose of your work, the evidence reviewed, the testing protocols, the raw data generated by your tests, the results, and your conclusions. Address weaknesses and contrary or inconclusive results. At trial you may be questioned about any part of your reports; therefore, it is a good idea to reference your file so that you can easily locate appropriate supporting data when testifying. Confer with counsel to ensure that your testimony and its implications are understood. If counsel assists in drafting your report or authoring your designation, review the final product in detail for accuracy. • You have no obligation before the trial to meet with the opposing attorney or to volunteer information to him. However, if requested, to prevent the appearance of bias, it is often better to do so. • During cross-examination, answer direct questions from the opposing attorney with concise but polite and complete responses. Admit any weaknesses in the evidence leading to your conclusions. This is often a very effective preemptive strategy, while failure to point out shortcomings may subject you to effective impeachment that could result in the jury ignoring all of your testimony. Do not spar with the opposing attorney and do not get angry or emotional. Emotionally charged, evasive responses to direct questions can undermine your demeanor of objectivity

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and professionalism. You may think you have won the battle, but the judge and jury will likely think otherwise. • Maintain your honesty, objectivity, and professional dignity. Treat counsel, the court, and opposing experts with respect. These practices will allow the jury to view you as a messenger of truth. • Have faith in the jury and the system. Believe that if you successfully convey a clear and concise explanation of the evidence, and the attorney coherently explains how the law should be applied to this evidence, justice will prevail.

References 1. The National Academy of Sciences. 2009. Strengthening forensic science in the United States: A path forward. Washington, D.C.: National Academies Press. 2. Daubert v. Merrell Dow Pharmaceuticals, Inc. 509 U.S. 579, 1993. 3. Mohan Rv. 2 S.C.R. 9, 1994. 4. Minasian v. Standard Charter Bank, 109 F.3d 1212, 1216 (7th Cir. 1997). 5. See, in general, American Bar Association, Model rules of professional conduct, preamble: A lawyer’s responsibilities. See also ABA model code of professional responsibility, preamble. 6. Model Rules 3.1, cmt (1). 7. Model Rules 3.3(a). 8. Model Rules 3.4; see also Model Code, EC 7–26 and DR 7–102.

29

Case Law Robert E. Barsley Contents 29.1 Introduction 29.2 Foundation 29.3 Qualification of the Expert 29.4 Forensic Dentistry and “Degree of Certainty” 29.5 Battling Experts 29.6 Qualifying to Testify, Particularly the First Time, for an Expert 29.7 Admission versus Weight of the Expert’s Testimony and Opinion 29.8 Beyond Linkage 29.9 Linkage to Objects Other Than Teeth 29.10 Even Further beyond Linkage 29.11 Expert for the Prosecution but Not the Defense 29.12 Testing the Expert 29.13 Conclusions References

29.1â•…Introduction This chapter will guide the reader through a basic understanding of American case law as it applies to the field of bitemark evidence. Some cases discussed earlier in the text will be revisited and numerous other cases will be discussed. FigureÂ€29.1 offers a lesson on understanding the legal citation system used in the United States. This simple system makes it easy for attorneys and other interested parties to communicate information about a case succinctly. It will be used throughout this chapter. What is meant by the term “case law”? In American jurisprudence, the principle of stare decisis—“to stand by that which is decided”—establishes the precedent to abide by or adhere to previously decided cases. Under this rule, a point of law, once settled by appellate decision, forms a precedent that is not afterward to be departed from unless a court finds it necessary to overrule a prior case that may have been hastily decided or was decided contrary to principle. Because the legal reporter volumes are filled with such overruled cases, one of the most important obligations of an attorney when researching the law is to be certain that any cases relied upon in making the necessary legal arguments have not been overruled by subsequent cases [1]: It is … a fundamental jurisprudential policy that prior applicable precedent usually must be followed even though the case, if considered anew, might be decided differently by the current justices. This policy … is

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based on the assumption that certainty, predictability and stability in the law are the major objectives of the legal system; i.e., that parties should be able to regulate their conduct and enter into relationships with reasonable assurance of the governing rules of law. MoradiShalal v. Fireman’s Fund Ins. Companies, 46 Cal.3d 287, 296 (1988)

An appeal court panel is “bound by decisions of prior panels unless an en banc decision, Supreme Court decision, or subsequent legislation undermines those decisions,” United States v. Washington, 872 F.2d 874, 880 (9th Cir. 1989) [2]. In the following pages, the words “citation omitted” indicate that the court is quoting from an earlier decision in its ruling. See the full text of the decision for the citation. A considerable amount of case law exists in the area of bitemark evidence in American jurisprudence. A query of the popular legal search engines using the terms “bite mark*,” “bitemark*,” “bite mark!,” or “bitemark!” (depending upon the search engine) will return hits in nearly every jurisdiction. Several observers maintain updated listings of appellate court cases containing those terms and one of the most recent contains over 360 cases [3]. Unfortunately, due to the mechanism of the American legal reporting system, many (perhaps most) of the cases and testimony involving bitemark evidence are not reported. Only cases that have been argued or heard before an appellate or supreme court on the specific issue of bitemark evidence would be discovered in such a search.

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Daubert v. Merrill Dow Pharmaceuticals, et al. (509 US 579, 1993) This is the full citation (also called the “style” of the case). Daubert v. Merrill Dow Pharmaceuticals, et al. The parties, decisions, or cases are often referred to by one of the parties. In this example, this decision is widely known as “Daubert.” Other such cases include the 1973 Roe v. Wade case, which commonly is referred to using both named parties. 509 US 579 This represents the reporter name, volume, and starting page number. The decisions of each appellate level court in the United States are published in an official text, called a “reporter.” Today, many are published online by the court as well. The first number (“509” in this example) refers to the volume (or book) number. The reporter name tells in which court system or state the case was decided. In this example, “US” stands for the United States Supreme Court. “LA” would stand for the Louisiana Supreme Court, “MS” for the Mississippi Supreme Court, and so on. Many states have now combined to issue their decisions in multistate volumes, such as the “So.3d,” which means the third edition of the southern reporter covering

states including Louisiana, Alabama, and Florida, among others. Some cases are reported in more than one reporter; for example, Daubert is also reported at 113 S.Ct. 2786. Finally, the “579” refers to the page upon which the current case report or decision begins. Often the case will be cited with a second page also listed (579, 583); the second number references the page upon which the precise language or point at issue can be found. Cases that are decided by intermediate-level appellate courts will have the name (abbreviated) of the court listed prior to the date. For example, the case Rinehart v. Barnes, 819 So.2d 564 (Miss. App. 2002), was decided by the Mississippi Court of Appeals. 1993 This is the date on which the decision was issued. Additional information about the case may be entered after the date. The words “cert. denied” denote that a higher court (usually the state or federal supreme court) declined to rehear the appeal. Similarly, the words “rehearing denied” denote that the same court has refused to reconsider the case. Cases may also be found on Web-based reporter systems. While these systems often have their own style of citation (most cases are available online well in advance of their actual book publication), the official citation and page breaks will be displayed as well.

Figure 29.1 Anatomy of a legal citation.

Since the prosecution is constitutionally barred from appealing a not guilty verdict in a criminal case, there can exist no appellate decisions for such cases. While the defense or prosecution might have appealed issues concerning admissibility of an expert after a guilty verdict, in every “not guilty” case, the gist of the testimony and associated evidentiary issues is lost. Consider for a moment if Milone had been found not guilty in Illinois in 1976 or Marx in California in 1975; then, two of the most oft cited appellate decisions about bitemarks would not even exist. It is therefore important to realize that the judge in the courtroom will declare much of the “law” involving a particular case. Please see the earlier discussion in this text on Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993) and the qualifications of an expert and several subsequent decisions since that case, such as Kumho Tire v. Carmichael, 526 U.S. 137 (1999), that declare the judge the gatekeeper for determining the admissibility of expert opinion.

One must also realize that there are parallel systems of laws and courts in America. Each of the 50 states operates an independent court system based upon the laws and constitution of the state. In general, neither the laws nor the court decisions of one state system have any bearing on the legal system of any other state. For the vast majority of legal cases (civil, criminal, and administrative), the decision of the state appellate or supreme court is the final decision. The federal court system adjudicates cases involving violations of federal law, decides disputes between citizens of differing states, and includes numerous specialized courts such as patent, bankruptcy, and military law. The federal circuit courts of appeal and, ultimately, the United States Supreme Court have final jurisdiction in these cases. Interestingly, while certain state criminal cases may reach the federal courts if violations of federal constitutional law apply, in civil cases in federal court, the

Case Law

federal judiciary often interprets the law of the state in which the case arose. What, then, can we learn about bitemarks from the case law? To date, no case has been overturned on appeal strictly on the issue of bitemark evidence alone, although in several cases the defendant has been exonerated through the use of DNA evidence that controverts the testimony of the prosecution’s forensic odontology expert—evidence that was not available at the time of the original trial. Similarly, no case has ever held as a matter of law that bitemark evidence is inadmissible; in fact, most courts have readily accepted dental experts (and others) in the field of bitemarks. Additionally, courts have accepted the expert opinion of forensic odontologists in fields of patterned injuries or marks made in human skin by objects other than teeth.

29.2 Foundation In order to testify, a forensic dentist must base his or her opinion upon an examination and analysis of the materials that comprise the case. How does case law bear upon this phase of bitemark evidence? As mentioned in previous chapters, the injury must be compared to the dentition(s) of the suspected biter(s) and other persons. Several constitutional principles are involved here. First, the gathering of this type of evidence must be either voluntarily consented to by the subject or the provisions of the Fourth Amendment to the U.S Constitution must be followed—a search warrant is required. To gain a search warrant, the investigating officer must demonstrate to the court probable cause potentially relating the subject (now a suspect) to the crime. It is well established in American case law that obtaining photographs and dental models of the suspect’s dentition does not violate the Fifth Amendment protection against self-incrimination. The surrender of these items is treated as any other exemplar such as handwriting, hair, blood, or DNA samples. Milone, in his first attempt to overturn his murder conviction, Illinois v. Milone, 356 N.E.2d 1350, IL App. (1976), alleged [4]: [T]he pictures of his mouth and the impressions made of his upper and lower teeth, pursuant to a search warrant, were seized in violation of his constitutional rights and that the trial court therefore erred in denying his motion to suppress such evidence. His first argument is that there was an absence of “probable cause” for the search warrant to issue and says that the affidavits are “so devoid of facts and replete with conclusions that it was impossible for the issuing magistrate to form an independent judgment as to the existence of probable cause.” A review of

519 the record shows that the judge was allowed, on the basis of the four affidavits, to determine for himself the persuasiveness of facts relied upon by the affiants and was not forced to rely merely on their conclusions.

After discussing the contents of and the circumstances surrounding the production of the affidavits, the court concluded [5]: [T]he affidavits attached to the complaint for warrant provided sufficient probable cause for the issuance of the search warrant. Having so held, we need not discuss the defendant’s further contention that this dental evidence was the direct result of an unlawful arrest. As the defendant concedes in his brief, the probable cause to search would also establish probable cause to arrest, and so taking the defendant into custody to obtain exemplars of his dentition was proper.

Milone continues [5]: The defendant also maintains that the techniques employed to obtain the dental evidence amounted to an unconstitutional invasion of his right to privacy and a violation of his privilege against self-incrimination. He relies upon Rochin v. California (citation omitted) where the United States Supreme Court found the act of pumping the defendant’s stomach against his will to be shocking and repulsive and therefore an invasion of his right to privacy. The situation in the instant case is not analogous. On January 24, 1973, the defendant was taken to a dental office in Wheaton, Illinois, and was asked to sit in a dentist’s chair, while photographs and impressions were taken of his teeth. The defendant did not resist, and at no time was the defendant harmed or put in an uncomfortable position. The dentist whose office was being used testified that the police treated the defendant courteously and at no time did he indicate any pain, discomfort or reluctance to have the procedure performed. The techniques used to examine the defendant and to take impressions of his teeth were in accordance with the standard practice, and we cannot find that such procedures were shocking and repulsive. The nature of the procedures and the manner in which they were performed did not invade the defendant’s right to privacy.

In the Wyoming case Seivewright v. State, 7 P.3d 24, WY (2000), when asked by the defense to hold a Daubert hearing to bar the testimony of a forensic odontologist, the court said: Because [the] motion for a Daubert hearing provided the district court with little reason to hold an evidentiary hearing to analyze [the dentist’s] testimony, we

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find no abuse of discretion in the district court’s refusal to hold such a hearing. [The] motion provided the district court neither with authority to establish the methodology or technique being applied was unreliable nor did it assert that another expert would refute reliability. In short, [the request] did nothing more than boldly assert that [the expert’s] testimony was unreliable. Under these circumstances, we conclude there was no abuse of discretion in the district court’s refusal to hold a Daubert hearing. Our conclusion on this issue requires examination of the scientific principle being applied. Bitemark identification is based on the theory of uniqueness. “Identification of a suspect by matching his dentition with a bite mark found on the victim of a crime [or a substance] rests on the theory that each person’s dentition is unique” [6].

Here the appellate court cites Giannelli and Imwinkelried [7] and other cases (citations omitted). The court continues [8]: Although several methods of bite mark analysis have been reported, “all methods involve three steps: (1) registration of the bite mark and the suspect’s dentition, (2) comparison of the dentition and bite mark, and (3) evaluation of the points of similarity or dissimilarity” (citation omitted). [The defense] does not seriously contend that bite mark identification is not a proper subject for expert testimony. Indeed, the courts faced with this question have unanimously concluded that bite mark comparison is a proper subject for expert testimony (citations omitted). While the majority of cases involve flesh bites, courts have also approved bite mark identification in cases involving various foods (citations omitted). Given the wide acceptance of bite mark identification testimony and [the defense’s] failure to present evidence challenging the methodology, we find no abuse of discretion in the district court’s refusal to hold an evidentiary hearing to analyze [the] testimony. The district court was simply exercising its “discretionary authority … to avoid unnecessary ‘reliability’ proceedings in ordinary cases where the reliability of an expert’s methods is properly taken for granted” (citation omitted). While this is not true for all subjects of expert testimony, we are comfortable that it is true under the circumstances of the case at bar.

An opposite result was reached by the courts in Illinois v. Dace, 506 N.E.2d 332, IL App. (1987) [8]: An essential portion of the State’s case against the defendant consisted of the testimony of three forensic odontologists who compared the teeth marks on the victim’s arm with the teeth of the defendant. Utilizing photographs and impressions of defendant’s teeth a comparison was made. The photographs and impressions were

obtained by executing a search warrant for them … on the complaint of Officer Baum of the Joliet police department. The photographs and impressions were taken the following day. The defendant prior to trial moved to suppress this information; however, said motion was denied. The precise question to be determined is whether the defendant’s rights under the Federal and State constitutions were violated because the warrant was illegally obtained because of lack of probable cause (citation omitted). An examination of the complaint for search warrant discloses that it contained only two allegations that relate to probable cause. It alleged that the defendant was the last person known to be present with the victim … while she was still alive … during the early morning hours of February 21, 1985. The complainant Baum made the further allegation that while interviewing the defendant on February 28, 1985, he was told by the defendant that he in fact was the last person in the club besides the victim and while there he entertained thoughts of having sex with her. The complaint did not indicate the time on February 21, 1985, when the victim’s body was found, nor did it attempt to indicate the time of her death … That defendant was the last person to be with the victim … during the early hours of February 21, 1985, may have given the police reason to suspect that he was involved in the homicide. Suspicion, however, does not constitute probable cause (citation omitted). The facts and circumstances within Officer Baum’s knowledge would not warrant a man of reasonable caution believing that the defendant committed the offense (citation omitted). We are unaware of any Illinois cases deciding the precise issue of whether probable cause exists where all the knowledge possessed by the police is that the defendant was the last person seen with the victim. A Federal case has held that such minimal knowledge does not support a finding of probable cause (citation omitted). To hold otherwise would be an invasion of constitutionally protected rights. It would permit intrusion upon the constitutional right to privacy and the seizure of fingerprint samples, blood samples, and dental impressions based upon suspicion and probability and not reasonable grounds or probable cause.

The search warrant should have, at a minimum, mentioned the bitemark on the victim. Another forensic dentist was rebuffed in the recent as of yet unpublished case, People v. Mostrong, 2003 Cal App. Unpub. LEXIS 1179, which barred a forensic dentist’s expert opinion offered for the defense to establish comparative negligence in an accident. The defense claimed [9]: Welter’s genital injuries were bite marks not caused by hitting the dirt after the collision. Defense counsel indicated the testimony was relevant to the defense that the

Case Law victims “were not paying attention, were not exercising due care and safety for themselves and … were the sole cause of the accident.” The prosecution countered that there was nothing in Welter’s medical records indicating the genital injuries were bite marks.

The prosecution objected that to admit the offered testimony would be highly prejudicial and countered by eventually dismissing the penalty enhancement on the criminal charge. While it would have allowed the testimony if the enhancement had been claimed [10], the court said: … reasoning the evidence was relevant and necessary to prove Mostrong did not cause the injuries. The court further indicated the evidence had only minor probative value if Welter’s injuries were not going to be considered on the enhancement issue, in light of the other evidence in the case of the victim’s contributory negligence and the fact the evidence might distract the jury. The court ultimately sustained the prosecution’s objection on relevancy … instructing the jury that the enhancement allegations were dismissed. After the court ruled, the defense continued to argue that the proffered evidence revealed Grady and Welter engaged in oral sex, that this explained why the car lights were off and it mitigated the gross negligence element of the alleged crime. The defense later renewed its request … offering a letter from [the expert] stating that Welter’s genital injuries were bite marks. The court again excluded the evidence, concluding the “misleading confusion” the evidence might have on the jury outweighed its probative value. A trial court has wide discretion in admitting and excluding expert testimony and the exercise of that discretion will not be disturbed on appeal unless it was clearly abused (citation omitted). We conclude the trial court properly excluded the evidence … Because the victims’ contributory negligence was not a defense, the trial court acted within its discretion when it concluded that the probative nature of the evidence was outweighed by the risk of confusing the issues by focusing the jury’s attention on the victims’ conduct, rather than on Mostrong’s conduct and the elements of the charged offenses. Even if exclusion of the testimony were error, it would not have affected the jury’s conclusions in this case because the evidence was merely cumulative.

Canadian forensic dentists have historically faced a more difficult time obtaining suspect dental information and exemplars. The case of R. V. Stillman, 37 W.C.B. (2d) 215 (1998), [11] made the finding that the police had no right to obtain the teeth impressions from the Appellant without his informed consent. The Appellant clearly expressed his refusal to provide bodily samples, yet by threat of

521 force the police obtained the sample … They proceeded with the lengthy and intrusive process of taking impressions of his teeth. There can be no doubt that the police, by their words and actions, compelled the Appellant to participate in providing the evidence. Equally, there can be no doubt that the evidence of bodily samples constituted conscriptive evidence.

In violation of the Charter of Rights a new trial was ordered. The Canadian Parliament has since enacted a section in the criminal code authorizing a justice to issue a warrant to obtain teeth impressions that became effective in June of 1997. In one respect, criminal law in Canada is more uniform than in the United States. Historically, the criminal system in England and its dominions stems from redress of offenses against the crown, so Canada has one set of criminal laws for the entire country. Unlike the United States, where each state develops its own criminal law and court system through its sovereign immunity, each Canadian province does not have separate criminal laws. In the Canadian court system, there are no individual provincial supreme courts, but rather only one single Supreme Court. Questions have also arisen over which type of permission for sample collection is preferred. While voluntary consent can be satisfactory, an argument can always be made that the subject was not fully aware of the gravity of the situation when he or she agreed to the collection and therefore would not have consented had he or she been fully informed. Similarly, the consent may not be adequately drafted to “protect” the “rights” or needs of the prosecution and thus may expose the evidence gathered through it to attack during litigation or trial or on appeal. The use of the search warrant is also subject to potential problems. A number of forensic dentists have anecdotally reported instances in which evidence collected under a search warrant was disallowed due to the absence of the named police officer at the site and time when the dental evidence was collected from the subject (although many search warrants use the language, “to any law enforcement officer in the state of ____,” or similar words). A search warrant may be subject to other attacks during trial. Therefore, this author prefers to operate at the command of a court order demanding that the subject present himself or herself to the dentist for the gathering of the specified exemplars. In the 1978 case of Vermont v. Howe, 386 A.2d 1125, VT (1978), the court discussed the case of United States v. Wade (citation omitted), stating that the taking of nontestimonial evidence pursuant to court order was not such a “critical stage” at which the defendant has the Sixth Amendment right to the presence of counsel [12]:

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Knowledge of the techniques of science and technology is sufficiently available, and the variables in techniques few enough, that the accused has the opportunity for a meaningful confrontation of the Government’s case at trial through the ordinary processes of crossexamination … they are not critical stages since there is minimal risk that his counsel’s absence at such stages might derogate from his right to a fair trial.

Although forensic dentists have also stated anecdotally that subjects have been ordered sedated to ensure the collection of dental evidence such as impressions, the author can find no appellate case directly on point. Winston and Davis v. Lee, 470 U.S. 753 (1985), in a case in which law enforcement officials sought to compel a victim of a crime to undergo surgery to retrieve a bullet that might constitute important evidence in that crime, held [13]: The Fourth Amendment is a vital safeguard of the right of the citizen to be free from unreasonable governmental intrusions into any area in which he has a reasonable expectation of privacy. Where the Court has found a lesser expectation of privacy, or where the search involves a minimal intrusion on privacy interests, the Court has held that the Fourth Amendment’s protections are correspondingly less stringent. Con versely, however, the Fourth Amendment’s command that searches be “reasonable” requires that when the State seeks to intrude upon an area in which our society recognizes a significantly heightened privacy interest, a more substantial justification is required to make the search “reasonable” (citations omitted).

No matter what type of device is selected to obtain dental exemplars, it remains critically important to discuss in advance with the investigating officers the number and types of exemplars that will be needed: two or more impressions of each dental arch, photographs of the teeth and face of the subject, radiographs (if desired), and the taking of a dental and/or medical history in order that all necessary material will be included in either the warrant or court order.

29.3 Qualification of the Expert What, then, have courts accepted as bitemark evidence, and who has been qualified as experts in these cases? It might surprise many readers to know that the testimony of a dentist is not always required to establish that a bitemark exists. In the seminal bitemark case Doyle v. State, 263 S.W.2d 779, TX App (1954), the court appeared to

give the greatest weight to testimony from a firearms examiner at the Texas Department of Public Safety who used caliper measurements from a plaster cast of the suspect’s exemplar bite into cheese to compare to the bitemark left by the perpetrator in a cheese at the crime scene. The court did note that a local dentist “examined the plaster casts and the photographs and gave his opinion that all were made by the same set of teeth” [14]. In the case Mobley v. Georgia, 441 S.E.2d 780, GA App (1994), the defendant at trial objected to opinion testimony concerning the bitemarks [15], as there was no expert witness to testify to it. The State responded that this was a matter for the jury to determine from the evidence, and the court agreed. The police officer later gave the complained-of testimony on direct examination without objection. On crossexamination, the officer referred to the “bite marks,” but when defense counsel corrected him by saying “alleged bite marks,” the officer agreed. Appellant requested a curative instruction that whether these were in fact bitemarks was for the jury to determine. The court ultimately charged the jury that it judges the facts and is not bound or concluded by the opinion testimony of any witness. This testimony was admissible. It was essentially [the police officer’s] way of describing what he saw, so the jury could visualize the same physical condition. “The opinion given by [the witness] was a conclusion or opinion based upon [his] personal observation of a physical fact and not an [expert] opinion. Description of one’s physical observations and opinions logically flowing therefrom have long been admissible in this state (citation omitted).” [Holding in that case] that a lay witness could testify that in her opinion bruises observed by her were caused by a shoe.

In a prisoner disciplinary matter, Hoskins v. McBride, 2000 U.S. Appeals LEXIS 27398, 7th Cir. (cert. denied), two inmates “were cited for fighting after a disturbance during prison recreation time.” According to the report of “two correctional officers … [one inmate] requested medical attention for injuries he said occurred while playing basketball. When the officers investigated further, they discovered a large quantity of blood on the wall and floor of the recreation area. They also learned that [the inmate] had sustained various injuries, including a bite on his left breast.” No expert testimony was required to establish the bona fides of the bitemark and hence the occurrence of the fight (which the inmates later denied ever occurred) [16]. In the case Louisiana v. Martin, 645 So.2d 190, LA (1994, rehearing denied), which was later upheld at Martin v. Cain, 246 F.3d 471, 5th Cir (2001), the testimony of the defendant’s cousin

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“established that the defendant had a bite mark on his shoulder” [17]. The testimony of a physician may or may not suffice to prove the existence of a bitemark. In an early case, Rhode Island v. Adams, 481 A.2d 718, RI (1984), stated [18]: It should have been apparent to the trial justice that [a forensic pathologist] was not testifying, to a reasonable degree of medical certainty, that the marks on the victim’s wrist were bite marks. Defense counsel had informed the trial justice at side bar that [the doctor] was not an expert in forensic dentistry. Moreover, defense counsel requested that if the prosecutor was going to be allowed to ask the question, then he should be required to answer within a reasonable degree of medical certainty. In light of the fact that he had been clearly forewarned by defense counsel, the trial justice committed error in overruling defense counsel’s objection to the question and in denying his motion to strike. This error is illuminated by the fact that [the forensic pathologist] admitted upon cross-examination that he could not state with any degree of medical certainty that the marks on the victim’s wrist were bite marks. As [he] testified, only an expert in forensic dentistry, which he is not, could testify to that degree of certainty.

This particular bitemark testimony was not allowed because, as the court said, “[i]n a long line of civil cases, this court has required that expert testimony must speak in terms of strong probability, not mere possibility” [19]. Contrast those cases with the unpublished case of Harris v. Arkansas, 1992 Ark. App. 728 LEXIS (1992): [T]he state medical examiner testified that the victim died by strangulation. He also noted the presence of a bite mark above the victim’s right breast. [Another] pathologist … examined the victim’s tissue to determine the age of the bite wound in relation to the victim’s death. He testified that the injury occurred within ten minutes prior to the cessation of heart activity.

After the physicians had established the fact that the injury was a bitemark, the state’s “forensic odontologist … compared photographs of the bite mark and dental impressions taken of appellant’s teeth. It was his opinion that appellant’s teeth had made the bite marks found on the victim.” The defense’s forensic dental expert “disputed the opinion of [the state’s dental expert] that the bite mark was made by the appellant. However, weighing the evidence, determining credibility, and resolving conflicts in the testimony are matters to be resolved by the fact finder (citation omitted). We cannot say there is no substantial evidence to support appellant’s conviction” [20].

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29.4 Forensic Dentistry and “Degree of Certainty” How then does the expert testimony of a dentist figure into this mélange? In an unpublished appellate decision, Draper v. Adams, 2000 U.S. App. Lexis 11826, 6th Cir (2000), speaking in an appeal that focused on ineffective assistance of counsel, the court was apparently satisfied with “[a]n expert in forensic dentistry [who] testified that the bite mark on Johnson’s back was made by Darian Draper, asserting that he was 90% plus certain of this conclusion” [21]. In another Louisiana case, Louisiana v. Vital, 505 So.2d 1006, LA App. (1987) [22], [a dentist] who testified at trial as an expert in the field of forensic dentistry, stated that he took photographs and made impressions of the bite marks left on the victim’s breast by the assailant. … After the dentist thoroughly described the procedure he used in comparing bitemarks, he stated as follows: “The bite on Miss Smothers has a high degree of consistency with that of Mister Vital to the point that I feel I can say that within a reasonable forensic or medical certainty that his teeth would have been able to make that bite mark.”

The court was satisfied with that degree of certainty. In Illinois v. Queen, 474 N.E.2d 786, IL App. (1985 rehearing denied), the state’s dental expert and the medical examiner [23] who performed the autopsy on the victim, testified that he found four bite marks on the victim’s body. [He] removed one of these bitemarks by excising the skin containing it; asked why he did not remove the others, he attributed his failure to do so to “stupidity” on his part. [A] dentist trained in forensic dentistry and oral surgery testified that he compared molds made of defendant’s dentures with the bitemark on the skin sample excised by [the medical examiner]. After testifying at length regarding his methodology, [the state’s dental expert] offered the following conclusion: Q. And based on what you have testified here today relating to your examination, doctor, your examination of the casts [sic] models, the skin specimen, the photographs, did you form an opinion within a reasonable degree of medical, dental certainty? A. Yes, I did. Q. Would you tell the ladies and gentlemen of [the] jury what that opinion is? A. Yes. When I examined this material I came to the conclusion that I could not exclude these dentures as being the mechanism for perpetrating these bite marks.

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Q. Why is it? What is it about those dentures that made you come to that conclusion? A. Well, I feel, when I initially started evaluating this case I went into it with a certain amount of reservance [sic] one dealing with some dentures. And I had some questions in my mind whether dentures could perpetrate a mark like this. So, I really strived throughout the entire investigation to exclude these dentures. I felt this was the best approach to take in this particular type of case. If I could find any portion of evidence that would exclude these dentures then I felt as though I would have done my job. When I finally concluded the valuation [sic] of the evidence I found nothing that I could definitely exclude these dentures on. Under re-cross-examination by defense counsel, [the expert] further explained the meaning of his conclusion [23]: Q. Doctor, the summation of your testimony is that these dentures could have made the bite marks. Is that right? A. My statement was that I could not exclude these dentures from making the mark. Q. All right. Does that mean the same thing to you as they could have made the bite mark? A. That means the same …

The court continued [23]: Where a verdict of guilty is returned by a jury, it is our duty not only to carefully consider the evidence, but to reverse the conviction “if the evidence is not sufficient to remove all reasonable doubt of the defendant’s guilt and is not sufficient to create an abiding conviction that he is guilty of the crime charged” (citations omitted). Upon careful examination of the record here, we are compelled to conclude that the State failed to prove the defendant guilty beyond a reasonable doubt … The forensic dentist who analyzed defendant’s dentures and the bite mark on the victim’s skin did not say that in his opinion defendant’s dentures caused the mark; rather, he could do no more than conclude that they could have done so, and that he could not exclude that possibility … The evidence simply does not establish defendant’s guilt beyond a reasonable doubt. We therefore reverse the judgment.

In the case Wisconsin v. Stinson, 397 N.W.2d 136, Wisc. App. (1986) [24]: [The] jury also heard from two expert witnesses who testified to a reasonable degree of scientific certainty that the multiple bite marks found on the victim’s body had been inflicted at or near the time of death. The experts

also concluded that Stinson was the only person who could have inflicted the bite marks on the victim. [The first expert] discovered multiple bite marks located on the victim’s body … [and] stated that the availability of bite marks from different parts of the body eliminated the possibility that the impressions obtained may have been distorted. He also testified as to the methods used in preserving and comparing the bite mark evidence gathered. A total of fourteen upper and lower jaw impressions were made from the bite marks found on [the victim’s] body. Because of the opportunity to examine so many bites, and the fact that some of the bites were so deep as to be three-dimensional, [the expert] testified he was able to detect a repetition of some particularly unique features in several of the bites. [He] later performed a forensic odontological examination of Stinson … [that allowed him to note] the following unique features: one of the central incisors was fractured and decayed almost to the gum line; the lateral incisor in the upper jaw was set back from the other teeth; all of the upper front teeth were flared; the lower right lateral incisor was worn to a pointed edge; the right incisor was set out from the other teeth on the lower jaw. [He then] used these features along with the arch of the mouth and the spacing, width, and alignment of the teeth to make comparisons with the bite marks found on the victim. After an exhaustive examination of the photos, models and tissue samples taken from Stinson and the victim, [he] concluded, to a reasonable degree of scientific certainty, that the bite marks on the victim were made by Stinson.

Continuing on in Stinson, the second dental expert [25] concluded, based on the workup … [already] performed on both the victim and Stinson, that Stinson had inflicted the bite marks on the victim. In [his] opinion the evidence in the case was overwhelming and he stated that “if we have four or five teeth that we are able to examine, then we can say that there is no other set of dentition like that.” In this case, [the first expert] was able to identify seventy-five individual tooth marks in various combinations of between five and eleven teeth. Based upon this evidence, we hold that a jury could reasonably conclude beyond a reasonable doubt that Stinson murdered [the victim]. The reliability of the bite mark evidence in this case was sufficient to exclude to a moral certainty every reasonable hypothesis of innocence.

In 2009 the conviction was set aside and the district attorney elected not to retry the defendant after DNA evidence taken from clothes the victim was wearing at the time of the attack excluded Mr. Stinson. The DNA was felt to have come from the saliva of the biter. Other

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forensic dentists who reviewed the case for the Innocence Project concluded that, even using the tools available at trial, the original forensic dentists should have excluded the defendant rather than included him [26]. The previously discussed case of Vermont v. Howe, 386 A.2d 1125, VT (1978), also mentioned the degree of certainty required of an expert. The trial court allowed the State to cross-examine an expert witness for appellant “on any matters which are material and in issue in this case.” This expert, a forensic odontologist, testified on direct examination that contrary to the opinion of the prosecution’s expert odontologist it was not possible to determine that a particular person was the maker of a bitemark to the exclusion of all others. The State was allowed on cross-examination to ask the defense expert if he had observed the models of appellant’s dentition and the photographs of the bitemarks and if so, whether the expert found the bitemark to be “consistent” with appellant’s dentition [27].

Apparently he agreed that they were and the court accepted “consistent” as the required degree of certainty [27]. As already noted in the previously discussed case Rhode Island v. Adams, the court said, “[T]his court has required that expert testimony must speak in terms of strong probability, not mere possibility” [28]. The degree of certainty was expressed as a mathematical probability by the forensic dentist in the case Arizona v. Garrison, 585 P.2d 563, AZ (1978) [29]: [T]here is an eight in one million probability that the teeth marks found on the deceased’s breasts were not made by appellant … [He] obtained the figure of eight in one million not from personal mathematical calculations, but from “articles written in the journals of the American Academy of Forensic Sciences” and two books, and “there are articles written throughout the literature that do mention the possibility or the numerical values of finding two [sets of teeth] of the [exact] same[ness].”

The court went on to state: [W]e do not think the admission of the eight in a million statement is reversible error. Were we to reverse on this ground, it would only result in a retrial at which the same evidence would be admitted since [his] testimony, obtained from published treatises and periodicals would be admissible … Courts should not engage in such futile practices.

That same year, in a neighboring state in the case People v. Slone, 143 Cal. Rptr. 61, Cal. App. (1978), three

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forensic dentists testified for the prosecution. After describing the tests and processes involved in arriving at their opinions, further testimony elicited that one of them [30] could not exclude defendant’s dentition … [He] found a minimum of 10 [ten] points of significant correlation between the bite mark that was on [the] body and defendant’s dentition. Of the 414 dentitions culled from thousands of records at the U.C.L.A. clinic, [he] found only three which had any points of similarity to the bite mark; he made wax impressions of these dentitions and studied them further. They were eventually ruled out.

The second expert for the prosecution [31] also studied the impressions made of the teeth of [five] other males who had seen [her] on December 19, 1975. By the use of slides as evidentiary exhibits, [he] concluded that these individual dentitions could not be matched positively with the bite mark on the victim. He testified concerning the three most similar models found at the U.C.L.A. Dental Clinic—and pointed out their essential dissimilarity with the bite mark replica.

The Court also ruled [32]: There is no merit to defendant’s corollary contention that by employing screening of thousands of cases at the U.C.L.A. Dental Clinic, the experts were attempting to impose mathematical probability statistics or odds on the fact-finding process, an evidentiary principle rejected by the California Supreme Court (citation omitted). The experts in the instant case were simply attempting to negate the potential disapproval of their scientific method in the area of specificity—the problem posed by the defense counsel, who inquired whether the experts could testify that no other human being on the planet could have bit the victim on the thigh. The expert witnesses were careful to say that they could not. There is a probability factor in even the most carefully structured scientific inquiry; seldom is it possible to exclude all possible chance for error in human endeavor. But there is no requirement in our law that the admissibility of scientific-test evidence must be predicated on a 100 percent degree of accuracy.

29.5 Battling Experts The issue of “hotly contested” bitemarks has frequently arisen in bitemark cases—first, with dental experts who have a fundamental disagreement: whether or not the injury in question even represents a bitemark at all. A

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second area that is subject to vigorous argument surrounds the certainty of any linkage between the suspected biter (often the criminal defendant) and the injured party. Several recent cases demonstrate these types of disagreements and the courts’ resolution of bitemark evidence issues. In State v. Duncan, 802 So.2d 533, LA (2001, cert. denied), the court was faced with the defendant’s appellate argument that the trial judge erred in prohibiting his expert “from showing the jury photographs depicting ‘actual’ bite marks. The ‘actual’ bite mark pictures, depicting bite marks made by unknown biters on the bodies of various unknown victims, were part of a booklet prepared by defendant’s expert.” Additionally, this booklet included several pages of written materials explaining the characteristics of bitemarks along with several pictures of the victim in the case [33]. In Duncan, the questions on appeal were whether the trial judge erred in ruling the booklet itself could not be used as demonstrative evidence. The second issue was “whether the judge erred in ruling the ‘actual’ bite mark pictures [from the booklet] could not be used … At trial, the issue of whether certain wounds on the victim’s body were bite marks was hotly contested.” The odontologist who testified on behalf of the state claimed that “several marks on the victim’s body were bite marks that with varying degrees of certainty matched defendant’s dentition.” The defense relied on two bitemark experts, one a forensic pathologist and the other a forensic odontologist. “Both defense experts testified that these marks on the victim’s body were not bite marks” at all. During the direct examination of their forensic odontological expert, “the defense sought to distribute to the jury the booklet … prepared to ‘educate’ them about what genuine bite marks look like.” The expert summarized the contents as follows: Generally the material is what I was given in 1996 on this case and it contains reprints from the odontology information on bite mark evaluation, terminology and standards for bite marks. It also has a section in there that has a series of bite marks of cases that I have done to show Juries what a real bite mark looks like and then a little demonstrative part in there to show them when we talk about how we identify people and what bite marks look like and how we can identify people by the class and individual characteristics.

The booklet contained 23 pages, the first 10 of which discussed bitemark analysis generally, and five photographs of bitemarks from other, unrelated cases. The remaining pages contained various photographs of the victim [34].

The Duncan decision echoed the trial judge’s sustaining the prosecution’s objection to the use of the booklet, ruling the testimony “needed to be restricted to evidence that has been presented in the case … [and that the] trial judge clearly was entitled to prohibit the defense’s expert from turning his courtroom into a classroom.” The defense odontologist’s testimony that none of the markings on the victim’s body were bite marks was premised, at least in part, on the fact that all of these marks were single arches (i.e., they lacked the corresponding other arch’s teeth prints) and his opinion that such single-arch bitemarks are rare [35]: In disallowing the photographs of bite marks on others (not the victim), the trial judge reasoned that it was the circumstantial use of such photographs that he found objectionable, stating: “If you’re going to use a picture now, look here’s a bite mark made on so and so over her[e] just look at the difference? Now, how is that fair?” The implication, the judge stated, is “that all bite marks have got to be like this. Now, the picture of [the victim] doesn’t look like that so that’s not a bite mark.” Still further, the judge reasoned that while [the doctor] could voice his opinion that there were no bite marks based on photographs of the victim “I don’t want him to show a picture of somebody else that’s bitten almost all the way through or more pronounced bite and say, ‘[N]ow here’s a bite mark, that’s not a bite mark.’”

In Duncan, the appellate court concluded that the defense was not precluded from “presenting a defense; rather, the trial judge allowed [the defense expert] to testify fully as to why he opined the marks on the victim’s body were not bite marks.” Additionally, the decision discusses other effective ways to educate jurors about bitemarks, such as having them bite themselves or taking “the mold of defendant’s dentition and [using] it to bite things like an apple, or people” [36]. Contrast that result with the outcome in a neighboring state when a similar dilemma was presented to the appeals court. In Kinney v. State of Arkansas, 868 S.W.2d 463, AR (1994), the odontologist for the state sought to introduce into evidence a photograph of another child’s penis (not the victim in the case) “to demonstrate bite marks on a penis” for the jury, which “was instructed that the pictures were from another case and not the present victim.” The defense alleged the picture was irrelevant and was used to inflame the jury and that if there were any relevancy to this picture, it was outweighed by unfair prejudice under the rules of evidence. The trial judge heard in-chambers arguments regarding the photograph. The state’s expert

Case Law explained to the judge that he used his previous experience, the photograph in question being one of those cases, to determine the origin of bite marks. The questioned photograph was known to be that of bite marks on an infant’s penis because the perpetrator in that case admitted to doing so. The trial judge admitted the photograph for demonstrative purposes only, and the jury was informed that this photograph was not of the victim.

The appeals court held [37]: [The] admissibility of photographs is a matter within the sound discretion of the trial court, and we do not reverse its rulings unless it abused its discretion (citation omitted). Even inflammatory photographs are admissible if they tend to shed light on an issue, enable a witness to better describe the objects portrayed, or enable the jury to better understand the testimony (citation omitted).

In the Duncan case, the state argued that the photographs in question were prejudicial and that their probative value was greatly outweighed by their potential to confuse or mislead the jury. A court in the state of Washington was faced with the question of whether or not a photograph of the defendant in Washington v. Kendrick, 736 P.2d 1079, Wash. App. (1987), with dental retractors in place to expose his teeth and gums, was gruesome. The defendant characterized the “pose as vampire-like.” The court ruled [38]: [It] is clear that … [the photograph’s] probative value outweighed any unfair prejudicial impact. The photograph of Kendrick’s teeth was offered in connection with the testimony of an odontologist who opined that Kendrick’s bite mark was consistent with the bite mark on [the victim’s] breast. The photographs aided the witness in explaining a rather complex theory. Moreover, the jury was told both why the photograph was necessary and why the dental retractors were employed in the taking of the photograph. It was therefore within the court’s discretion to admit the challenged photographs.

An often more hotly contested area of disagreement between forensic odontologists concerns the linkage of a particular suspect’s teeth to a bite injury. Perhaps the most discussed and quoted case is that of Richard Milone, convicted in 1973 in a bench trial (no jury) of the murder of Sally Kandell, Illinois v. Milone, 356 N.E.2d 1350, Ill App (1976): The [trial] record contains over 1300 pages of dental testimony and numerous exhibits including photographs and impressions which were admitted into evidence at trial.

527 Briefly, this evidence included the testimony of three State expert witnesses who asserted that, in their opinion, Richard Milone was without a doubt the perpetrator of the bite on the victim’s thigh. The defendant, on the other hand, presented four expert witnesses who concluded that no positive correlation could be made between the defendant’s dentition and the bite mark in question.

The body was found in a state of extreme rigor mortis and taken to the morgue, where the bitemark was observed and photographed [39]: [An] impression of the bite mark was made and clear plastic overlays were placed on the wound and the markings were traced on the plastic. These exhibits, along with the pictures and casts of the defendant’s teeth provided the basis for the comparison made by all of the experts. There was ample testimony that because of the advanced state of rigor mortis, the victim’s leg was immobile and thus there could be no distortion of the bite mark resulting from movement of the leg. … [The] State’s leading expert testified that, in terms of quality for comparison purposes, the bite mark on the victim’s thigh was an excellent specimen. The marks were clear, the quality of the marks was good, and because the victim was already deceased when the bite was inflicted, the skin and underlying tissue provided an unchanging medium for the marks. As the most experienced of the expert witnesses, [he] testified that in the course of his work as a dentist and instructor in forensic dentistry he had seen between 200 and 300 bite marks in human skin and had been called upon to give his opinion in five bite-mark cases. In comparing the defendant’s dentition to the bite mark in the instant case, [he] enumerated 29 points of comparison between the marks and the defendant’s dentition which led him to identify positively the defendant as the perpetrator of the bite. In addition, [he] was able to produce an explanation for the distortion which appeared in one segment of the bite mark by inflicting bite marks on human skin, with casts of defendant’s teeth.

In Milone, a second expert for the state [40], an orthodontist for 20 years and chairman of the Department of Orthodontics at Northwestern Dental School, testified that he had seen over 40,000 casts of teeth in his work and that in his opinion, every individual’s dentition is as distinct as his fingerprints. He concurred with the positive identification made by [the first state’s expert] and pointed out that less than 1% of the population would have a fracture of the left central incisor as was observed in the casts of the defendant’s teeth and the bite mark on the victim. He stated that this correlation, along with a number of other outstanding characteristics present in both the mark and

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the defendant’s dentition, could leave no doubt that defendant had inflicted the bite.

In this case, the third state’s expert, a dentist and forensic pathologist [41], testified that, compared to numerous bite marks he had seen on human bodies or read about in forensic literature, the bite mark in question was good in terms of definity of points, clarity, lack of distortion, and lack of decompositional change. He also found numerous unique and specific points of identification which enabled him to concur with the other State experts in their positive identification of Richard Milone as the perpetrator of the bite.

In contrast to the prosecution’s experts [42]: The four forensic odontologists called by the defendant testified that it is far easier to exclude a suspect through bite-mark comparison than to positively identify a subject through the marks left by his teeth. All four pointed out areas of inconsistency between the bite mark and the moulds of defendant’s teeth, and for this reason either denied that a positive identification could be made, or specifically ruled out the defendant as the person responsible for the tooth marks on the victim.

“In rebuttal, the State witnesses explained why the inconsistencies pointed out by the defense experts existed, and steadfastly held that defendant’s teeth made the impression on the victim’s thigh.” In its discussion of the dental evidence, the court commented [43]: The record in this case reflects the utmost diligence and care in preparation by the investigating police, the State’s Attorney, and counsel for the defendant. It must be realized that our synopsis of the dental testimony hardly does justice to the 1300 pages of intense examination which took place at trial, and, without the painstaking care exercised in preserving evidence, none of the dental testimony would have been available. Had the quality of the scientific or legal preparation been less thorough, we might have given less credence to this entire area of inquiry.

Milone’s counsel contended: [The] State should have been precluded from introducing such evidence to identify him as the perpetrator of the bite mark because under the then prevailing Frye Test he claimed that bite-mark identification as a science has not “gained general acceptance in the particular field in which it belongs,” and therefore should not be admissible in a court of law.

Offering statements made by four forensic odontologists to support this contention that downplayed the ability of bite marks to link a biter and a bite, the court stated that the statements relied upon were not dispositive in the case at bar [44]: A lack of complete unanimity in the medical profession as to the reliability of certain scientific testimony does not mean that such testimony fails to satisfy the requirements of Frye … Bite-mark comparison … involves only a visual comparison between the wound and the dentition of the defendant. The great care taken to preserve and gather the physical evidence in this case precludes any problems arising in regard to the quality of the exhibits being compared. For this reason, the testimony of the experts serves only to lend assistance to the trial court in interpreting physical evidence not within the ken of the average trial judge’s knowledge. There is no intermediate mechanical stage in which reliability may be questioned. Such evidence is more analogous to footprint, fingerprint, and hair comparisons which are made for purposes of identification … The court differentiated between the interpretation of mechanical measurements such as print-outs from a polygraph, and testimony based upon direct observation of physical characteristics such as the characteristics of a bite mark and the known dentition of a suspect.

The Milone court cited the earlier Illinois case of People v. Mattox, 237 N.E.2d 845, Ill. App. (1968), in which the court stated [45]: Although a question of first impression in this State, it cannot be seriously disputed that a dental structure may constitute a means of identifying a deceased person, otherwise unrecognizable, where there is some dental record of that person with which the structure may be compared. Comparison of dental structures falls within the category of circumstantial evidence and involves the question of weight and credibility, rather than that of competency.

Having thus taken judicial notice that the unique quality of an individual’s dentition had already been recognized for purposes of body identification, the court in Milone reasoned that “[t]he concept of identifying a suspect by matching his dentition to a bite mark found at the scene of a crime is a logical extension of the accepted principle that each person’s dentition is unique” [46]. The court went on to cite numerous cases in other jurisdictions, along with articles in scientific and legal journals, to show that [47] the trial judge was correct in allowing expert testimony to aid his comparison between the bite mark on Sally

Case Law Kandel’s thigh and the dentition of the defendant. The weight given this testimony was within the province of the court, and nothing in the record indicates that the trial judge abused his discretion in allowing the testimony. Keeping in mind the excellent quality of the dental evidence introduced at trial, we conclude and hold that it was properly admitted.

Ten years later, in an appeal in the federal court system, Milone v. Camp, 22 F.2d 693, 2nd Cir. (1994, cert. denied), the court found: Milone raises several issues in his habeas petition that were not presented to any state court. He wishes the Court to excuse his failure to exhaust all of his state remedies on the ground that it would constitute a miscarriage of justice, due to his innocence of the murder, not to entertain his petition. In support of his claim of actual innocence Milone makes the following points: 1) The evidence presented at his trial that linked his dentition to the bite mark found on Sally’s thigh was unreliable. First, it failed both the Frye and the Daubert tests of admissibility of scientific evidence because the science of “forensic odontology” was in its infancy at the time of his 1973 trial. Second, expert testimony is now available (and is reliable because the science of forensic odontology has advanced considerably in the past 20 years) tending to show that Milone could not have made the mark found on Sally’s thigh. Indeed, the mark on Sally’s thigh can now be shown to match the dentition of a known serial murderer, Richard Macek. 2) Richard Macek confessed to the murder of Sally Kandel several times before committing suicide in his jail cell in 1987. (The parties dispute whether Macek also recanted these confessions.)

The federal appeals court continued [48]: [The] admissibility of evidence is generally a matter of state law (citations omitted). In this case, the Illinois Appellate Court held that the state’s expert testimony was admissible. Absent a showing that the admission of the evidence violated a specific constitutional guarantee, a federal court can issue a writ of habeas corpus on the basis of a state court evidentiary ruling only when that ruling violated the defendant’s right to due process by denying him a fundamentally fair trial. The standard, then, is not whether the testimony satisfied the Frye or Daubert tests neither of which purports to set a constitutional floor on the admissibility of scientific evidence but rather is whether the probative value of the state’s evidence was so greatly outweighed by its prejudice to Milone that its admission denied him a

529 fundamentally fair trial. It is clear that the probative value of the odontology evidence presented by the state was not so outweighed by its prejudice to Milone as to deny him a fundamentally fair trial. With respect to its probative value, while the science of forensic odontology might have been in its infancy at the time of trial, as Milone asserts, certainly there is some probative value to comparing an accused’s dentition to bite marks found on the victim. With respect to the prejudice to Milone caused by the admission of what he claims was unreliable evidence, he had ample opportunity to persuade the trial judge to discount the testimony of the state’s expert: Milone was able to cross-examine the state’s expert both in regard to his credentials and in regard to the general reliability of the science of bite mark identification, and Milone presented several experts of his own to testify that he could not have made the mark found on Sally’s thigh. Accordingly, it was not constitutional error for Illinois to have allowed the admission of the bite mark evidence … [T]he evidence adduced against Milone at trial reveals that there was sufficient evidence to support his conviction. He had an opportunity to commit the crime, he was linked to the murder weapon, and evidence was introduced from which a reasonable finder of fact could conclude that Milone was observed near the scene of the murder and that his dentition was linked to the bite mark found on the victim.

29.6 Qualifying to Testify, Particularly the First Time, for an Expert How then does the dentist initially get into court? The following cases describe the reasoning of various courts when facing forensic dentists who were making their first foray into the courtroom, either in general or as an expert in bitemarks. In the 1977 case Niehaus v. Indiana, 359 N.E.2d 513, IN (1977), the state’s expert [49] acknowledged that the identification of suspects by this manner of comparison between marks in human tissue and the teeth of suspects was a relatively new procedure and had not yet been extensively used. He further acknowledged that this was the first occasion of his having personally undertaken such a determination. From this, the defendant contends that the field is not sufficiently recognized for reliability as to qualify as an area of expertise and that [the doctor] was not sufficiently experienced in the area to qualify as an expert … [T]he defendant relies upon holdings excluding evidence of polygraph test results as not being sufficiently reliable … The method of identification utilized here, however, is simply a matter of comparison of items of physical evidence

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to determine if they are reciprocal. The methods for making such comparisons are indeed complex and require skilled technicians to perform, but they consist of standardized procedures known to procure accurate models and measu rements. We see no reason why such evidence should be rejected as unreliable, simply because it has thus far had limited application. As for the qualifications of [the expert], we deem it unnecessary to go into great detail. His testimony revealed that he was a graduate dentist with some thirty years of practice and teaching experience. He had become interested in this subject several years earlier, had attended twelve to fifteen lectures and read thirty to forty articles upon the subject by others experienced in the field. The determination of whether a witness is qualified to testify as an expert lies in the sound discretion of the trial court and may not be set aside unless there is manifest abuse of discretion (citations omitted).

Three years later in Kansas, another court, in Kansas v. Peoples, 605 P.2d 135, KS (1980)—a case in which the admissibility of expert testimony on bitemark identification was a matter of first impression in Kansas—citing the language of the Niehaus case, held [50]: We think bite-mark identification by an expert witness is sufficiently reliable and can be a valuable aid to a jury in understanding and interpreting evidence in a criminal case. When the witness has the requisite skill and experience, and demonstrates the accuracy and reliability of his models, photographs, X-rays and supporting exhibits in bite-mark identification, the trial court in the exercise of its power of discretion may properly admit the opinion testimony of the expert witness.

The defendant also challenged the admission of the state’s dental expert’s opinion testimony [51], claiming that an inadequate foundation was presented to qualify [him] as an expert, and that the exhibits and models were inaccurate. [The state’s expert] described himself as a general dentist, specializing in forensic odontology. He was a … graduate of Northwestern University, and served five years in the military before entering private practice. He is a certified diplomat[e] of the American Board of Forensic Odontologists, a fellow in the American Academy of Forensic Sciences, and a member of the American Society of Forensic Odontology. He teaches forensic odontology to senior students and provides continuing education courses for graduate dentists at the University of Colorado School of Dentistry … [and] has been a consultant for various law enforcement agencies, including the Kansas and Colorado Bureaus of Investigation. He has attended many lectures and seminars on forensic odontology

and is acquainted with the major literature and experts in the field of bite-mark identification. [He] testified at length about the various procedures and practices underlying bite-mark identification. The testimony spans more than 150 pages in the record. He discussed the manner of comparing dental casts, wax impressions, and photographs. He also testified to the numerous factors that are considered in bite-mark identification. In comparing the appellant’s dentition with the bite marks … us[ing] casts and photos of the appellant’s teeth and compar[ing] those to the bite marks shown in the photographs of the victim … [and] several photographic enlargements of the bite marks, the cast of the appellant’s teeth, and the wax imprints to illustrate the many shared characteristics of the teeth and the bite marks. All of these exhibits and models were admitted into evidence. After explaining the procedure he used to develop the exhibits and identify the many important points of comparison, [he] gave his opinion. He testified that in his opinion it was highly probable that the appellant had bitten the left breast of [the victim].

The appellate court continued [52]: After carefully reviewing the detailed testimony … we find no error in the trial court’s admission of his testimony. [The doctor] was sufficiently qualified to be an expert witness and provided an adequate foundation for his testimony. He was shown to have special skill and expertise in the field of forensic odontology, and was qualified to impart this otherwise unavailable knowledge to the jury (citation omitted). The appellant specifically challenges “the use and admission of a set of dental casts and several enlarged photographs.” [The state’s expert] testified to the origin and production of those exhibits and stated he found them reliable and acceptable for his use. The trial court did not abuse its discretion in admitting those exhibits. Any discrepancies go to the weight of that evidence, and the testimony based upon it, and are properly a matter for the jury (citations omitted).

Six years later, the Supreme Court of Massachu setts, in Commonwealth v. Cifizzari, 492 N.E.2d 357, MA (1986)—another case of first impression—“summarize[d] the experts’ testimony in some detail because the major issue raised in this appeal is the admissibility of their opinions” [53]. The court stated [54]: [The] admissibility of expert dental witnesses’ testimony does not depend on meeting the Frye test. The experts’ testimony merely aided the jury in comparing the photographs of the bite marks with the defendant’s dental impressions. The [trial] judge, in expressing his position that perhaps expert testimony was not necessary on the subject, reached the core issue which is that

Case Law bite mark evidence is merely a valuable tool to the jury in understanding and interpreting the evidence.

The court went on to note that “[o]ther jurisdictions that generally follow the principles of the Frye test have reached the same conclusion that we have concerning the admissibility of expert testimony concerning bite marks (citations omitted).” The court then cited the California case of Marx, holding that [55] the determination of general acceptance of bite mark identification in the scientific community goes to the weight rather than admissibility of the evidence … It was open to defense counsel to impeach the doctors as to the methods used. Defense counsel raised the issue that skin elasticity, blood pressure, and plane variations, as affecting the photographs, could have some effect on the reliability of the doctor’s ultimate conclusions.

Fourteen years later, a court in the Louisiana case Louisiana v. Wommack, 770 So.2d 365, LA App. (2000), discussed a defense attack on the testimony from two experts, one an oral surgeon and the other a forensic pathologist [56]: Before accepting the testimony of the experts, the trial court conducted a hearing pursuant to Daubert v. Merrell Dow Pharmaceuticals, Inc. (citation omitted). Commenting on Daubert and its applicability in Louisiana cases, a panel of this court has explained: In Daubert, the Supreme Court suggested that the trial court should consider four factors in determining whether expert scientific evidence is reliable: (1) whether the theory or technique can be, and has been, tested; (2) whether it has been subjected to peer review and publication; (3) the known or potential rate of error of the theory or technique; and (4) whether the theory or technique is generally accepted in the scientific community … The [State] relies upon La. Code of Evidence Article 702, which states: If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education may testify thereto in the form of an opinion or otherwise.

The court continued [57–59]: Although the trial court considered the expert testimony in a separate hearing, the Daubert standards do not appear to be readily applicable to the present case. Neither expert used complex testing in identifying the wound found on Wommack’s arm. In simplest terms, [the oral surgeon] made his determinations after inspecting the wound within days of the offense and

531 [the pathologist] reached his opinion after looking at pictures of it. Expert opinion testimony based upon personal observation and experience is admissible (citation omitted). [The oral surgeon’s] testimony at the Daubert hearing revealed his significant background in various aspects of dentistry and oral surgery. After conducting an extensive Daubert hearing, the trial court concluded that [the oral surgeon] had sufficient experience and training to identify Wommack’s wound as a human bite-mark. The court further ruled that [he] would not be allowed to testify regarding the age of the mark, or to identify it as matching the victim’s dental pattern. In view of [his] extensive experience, we conclude that the lower court did not abuse its discretion in accepting him as an expert. The other expert who testified about the bite … did not personally examine the defendant. Rather, he viewed photographs of the wound the week prior to trial. At the Daubert hearing, [he] testified that he had no special training in bite-mark identification and had never given testimony on the subject. Although he works as a forensic pathologist, [he] is not board certified. He noted that along with being the coroner for Calcasieu Parish, he is the jail physician … [and] stated that he has seen human bite-marks and is familiar with their appearance. He sees bite-marks from jail fights once or twice per year. He reviewed the photographs of Wommack’s wound and formed the opinion that it resulted from a human bite … [H]e could testify whether or not the wound was consistent with a human bite. On cross-examination, he estimated his error rate would be approximately forty-nine percent. He used the same figure at trial, but on redirect placed the error rate closer to ten percent. Considering the transcript of the hearing, we do not find that the lower court abused its discretion in accepting [the pathologist] as an expert. Further, even if [his] testimony regarding Wommack’s wound should have been excluded, we find any such error harmless. As discussed above … an oral-maxillofacial surgeon presented strong credentials and testified the wound was a human bite-mark. The jury was also presented with numerous photographs of the wound found on the defendant’s arm. These assignments [of error] have no merit.

In the previously discussed case Seivewright v. State, 7 P.3d 24, WY (2000), the court was faced with another challenge to a dentist testifying about a bitemark. In answering the defense’s contention that the expert was not “board certified,” the appellate court responded: The chief complaint is that [he] was not qualified to offer expert testimony because he is not certified by the American Board of Forensic Odontologists [sic] (ABFO), which has established standards for qualification to testify as an expert in the field of forensic odontology. [The defense] directs us to no authority

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establishing that ABFO certification is a prerequisite to testifying as an expert in the field of forensic odontology. Indeed, an expert need only have sufficient “knowledge, skill, experience, training, or education” to qualify as an expert (citation omitted). Therefore, the question is simply whether [he] was qualified to testify despite his lack of ABFO certification. The record establishes that [he] has been a practicing orthodontist for nearly 20 years. In addition to being a board certified orthodontist with a master’s degree in the field, he previously qualified to testify as an expert. He has also worked in the field of forensic odontology, for the local coroner, since 1980 and has completed numerous courses in that field. Given these credentials, we can find no abuse of discretion in permitting [him] to testify despite his lack of ABFO certification (citation omitted; “An expert need only have experience and knowledge which is not common to the world.”).

The decision continued [60]: [The defense] also complains [the dentist] was not qualified to testify because of admissions the doctor made under cross-examination. In addition to admitting he was not an expert, but “most qualified,” [the dentist] stated that, without training as a dentist or orthodontist, even … trial counsel could have rendered an opinion on whether a particular person took a bite of a piece of cheese. It is, however, the function of the jury to sort out the weaknesses and the strengths of expert testimony (citations omitted; “Vigorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means of attacking shaky but admissible evidence.”) … and we conclude [his] statements go to the weight to be given his testimony, and not to admissibility. Finally, [the complained-of] testimony was more involved than his admission under cross-examination would indicate and thus helpful to the trier of fact. Not only did he make the impressions of the cheese and [the defendant’s] teeth, [the dentist] performed a more thorough examination than the naked-eye analysis suggested by defense counsel … [explaining] how he measured the teeth spacings in reaching his conclusions, explain[ing] in detail the peculiar idiosyncrasies [sic] found in [the defendant’s] dentition, and ultimately concluded that [the defendant] had bitten the cheese. The testimony was thus helpful to the trier of fact, and we find no abuse of discretion in its admission.

29.7 Admission versus Weight of the Expert’s Testimony and Opinion An interesting case from Illinois describes the court’s findings when the state’s expert dentist was challenged

by the defense upon changing his expert opinion. In Illinois v. Holmes, 601 N.E.2d 985, IL App (1992), the first forensic dental report attributed different teeth of the same suspect to several bite injuries. In addition, the state’s expert was allowed to testify as to his opinion on the manipulation of the injured area that must have occurred in order for the bites to have attained their size and shape, as well as why certain teeth made no marks. The discovery of an additional photograph of the injured area taken by the medical examiner’s office but not originally furnished to him allowed him to reissue an amended report linking different teeth of the same suspect to the injured areas. A second state’s forensic dentist agreed with the testimony [61]. The first defense forensic dentist [62] testified that the injuries found on the victim’s body were not bite marks at all. With respect to the injuries on the victim’s jaw, [he] said he had difficulty analyzing how the bite marks could have been inflicted in the direction that these marks made in the absence of a drag pattern … he noticed that the drag patterns went in the opposite direction of the alleged bite mark … [and he] explained that it would have been physically impossible for defendant to have inflicted the mark because his head would have been in the way. He reached this conclusion after attempting unsuccessfully to place a model of a head in such a position that a bite mark could have been inflicted.

The second defense expert “stated that the injuries on the right side of the victim’s jaw were not bite marks. He explained that he saw a series of different types of injuries in that area and that they lacked the pattern of a bite mark.” The court concluded [63]: With regard to defendant’s argument that the State’s experts assumed facts not in evidence, the State maintains that [the state’s expert’s] opinion that defendant’s teeth caught on the victim’s T-shirt was a plausible explanation for the lack of lower teeth marks and that his opinion was supported by evidence which showed that the victim was wearing a T-shirt which was pulled up near her breast. Although it appears that [the state’s expert] was speculating that defendant’s teeth may have caught on the victim’s shirt in order to explain the lack of a corresponding set of marks on the clavicle injury, and assuming that the court erred in admitting such testimony, its ruling should not be reversed absent a clear showing that the trial court abused its discretion to the manifest prejudice of the defendant (citation omitted). Moreover, regarding defendant’s argument that the State’s experts’ testimony was impeached, as the State points out, the credibility of an expert is a matter for the trier of fact to determine (citation omitted), and

Case Law if expert testimony is conflicting, the reviewing court should not substitute its judgment for that of the trier of fact (citation omitted). We note further that the ultimate issue is for the court and not the expert to decide (citation omitted).

In a 1996 federal appeal of his 1985 murder conviction, Spence v. Scott, 80 F.3d 989, 5th Cir. (1996, cert. denied), the defendant complained [64]: [T]he district court erred in not holding a hearing on his challenge to the admission of testimony by the State’s forensic odontologist … Spence contends that, because he submitted materials challenging [the expert’s] methodology and conclusions, the district court should have held a hearing to determine whether the admission of [that] testimony violated the Eighth Amendment’s requirement of “heightened reliability” under Johnson v. Mississippi (citation omitted). Johnson is, however, inapplicable to the instant case. In Johnson, the Supreme Court vacated the death sentence because the jury had been allowed to consider evidence that was false.

In a footnote, the court stated that the false evidence was “the sole piece of documentary evidence of any relevance to [the State’s] sentencing decision. In the instant case, much other evidence demonstrated Spence’s guilt” [65]. The decision went on to state [66]: Spence does not raise a question over whether [the forensic dentist’s] testimony is false, but rather over what weight the jury should have accorded his testimony. Spence’s argument that [the expert] had misidentified the remains of another woman likewise does not expose his testimony against Spence as false.

The court concluded: Spence is simply trying to re-litigate this aspect of his defense eleven years too late. At trial, Spence introduced his own forensic odontologist … a leading expert in the field. [He] spiritedly criticized [the state’s expert’s] methodology and conclusions, although, critically, [he] admitted he could not rule out Spence’s teeth as the source of the bite marks. Because this evidentiary issue was fully and competently aired in the state courts, no violation of fundamental fairness under the due process clause has been shown (citation omitted). Alternatively, Spence argues that the federal district court erred in excluding reports from five other expert odontologists who concluded that [the state’s expert’s] testimony was unreliable. But because Spence filed these reports after the district court’s discovery deadline, without explanation for his untimely filing, the district court did not abuse his discretion in refusing to admit the reports.

533

The conviction was upheld [67]. The 1978 case from the U.S. Military Justice System, U.S. v. Martin, 9 M.J. 731, USNCMR (1978)—later overturned on other grounds as Monk v. Zelez, 901 F.2d 885, 10th Cir. (1990) [68]—was another of first impression for military courts. The court noted [69]: The record unquestionably established that … is an expert in the field of bite-mark identification. He was so recognized at trial by … a witness for the appellant, another expert in this very limited field of about 30 individuals nationwide. There were, as might be expected, differences of opinion in this case between the expert for the Government and the expert for the defense, but these differences go to the weight rather than to the admissibility (citation omitted). … These gentlemen both displayed impressive qualifications, training, and experience in their field of expertise and both ably acquitted themselves during direct and cross-examination. The members [jury] no doubt fully considered and weighed the content of the expert testimony and opinions in reaching a verdict in this case … We find no merit to this assignment of error.

29.8 Beyond Linkage Several courts have recognized that a bitemark is an indication of a violent interaction between two individuals. In a long-running attempt to overturn his conviction for a second murder within a dozen years, a Virginia prisoner challenged his conviction on numerous occasions. One was Tuggle v. Nederland, 79 F.3d 1386, 4th Cir. (1996)—original conviction appealed as Tuggle v. Virginia, 334 S.E.2d 838 VA (1985, cert. denied 1986)—[70]: [T]he medical examiner testified that both the bite mark on the breast and the bruising around the vagina occurred while [the victim] was alive … A forensic odontologist testified that he examined the bite mark on the victim’s right breast. He compared the mark with models of Tuggle’s teeth and concluded “with all medical certainty these marks on the body of [the victim] were made by the teeth of Mr. Tuggle.” He further opined that [the victim] was alive and moving when she was bitten.

The court agreed that such evidence was an “aggravating circumstance, and the murder in this case was unquestionably vile. The murder involved rape and sodomy, and Tuggle bit [the victim] on the breast before shooting her in the chest” [71]. These findings contributed to the imposition of the sentence of death.

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In the previously discussed Hoskins [72] case from 2000, the presence of the bitemark was presumptive proof that a fight rather than an accident was the root cause for the altercation. Similarly, in the Martin [73] case discussed earlier, the bitemark on the suspect was part of a triad of injuries that the court accepted as evidence of aggravated rape. In the recent case of Gilliam v. Florida, 817 So.2d 768, FL (2002, rehearing denied), “an expert in forensic dentistry testified that the pattern of bite marks on the victim’s breast indicated that she was more than likely moving at the time the injury was inflicted.” In combination with testimony from the medical examiner that the victim did not lose consciousness during the commission of the crime, this evidence was sufficient to enhance the penalty levied as a heinous, atrocious, or cruel finding (HAC) under Florida law [74]. In another case from 2002, U.S.A. v. Kills in Water, 293 F.3d 432, 8th Cir (2002) [75], the district court did not automatically apply the serious bodily injury enhancement. Instead, the district court specifically relied on the victim’s bitemarks, her physical trauma to the vaginal and perianal areas, her continued psychological problems such as recurring nightmares and attempted suicide, and her ongoing need for psychological counseling, as the basis for concluding that the victim suffered serious bodily injury.

In a footnote to this case, the court said [76]: Defendant argues that the bite marks should not be considered in assessing his sentence because the codefendant, not he, actually bit the victim during the rape. However, we agree with the district court’s conclusion that defendant’s participation in the biting by holding the victim down while his co-defendant bit her is sufficient to render defendant liable for the resultant bite marks during sentencing.

29.9 Linkage to Objects Other Than Teeth In an unpublished 1992 Illinois case, People v. Cumbee [77], after ruling out the presence of any bite injuries on the victim, a forensic dentist was called upon by the state to testify as a layman regarding the interpretation and classification of the victim’s blunt trauma wounds. The judge ordered a hearing to assess the dentist’s fitness to testify in these matters, at which the dentist readily admitted that he was not a pathologist, that he was not regularly consulted in such matters, and that he had never previously been qualified to testify in a court of law concerning blunt trauma wounds not caused

by teeth. In spite of these admissions, the dentist was allowed to testify. The appellate court found that the trial court abused its discretion in allowing the testimony because the dentist’s qualifications were in fact not sufficient. In Cumbee v. Nygren, 2000 U.S. App LEXIS 3148 (7th Cir., 2000), the federal appellate court noted that “the trial court both failed to properly instruct the jury regarding the prosecution’s burden to prove venue and also admitted improper evidence, a state appellate court reversed his conviction and ordered that Cumbee be retried” [78]. In a recent decision by the Mississippi Supreme Court, the testimony of a forensic dentist as to the bitemark injuries on the victim not only was accepted, but a much broader range of opinion testimony also was allowed. In Stubbs and Vance v. Mississippi, 845 So.2d 656, MS (2003, rehearings denied), the appellate court upheld convictions for numerous criminal acts committed by the defendants [79]: The State next called … a forensic odontologist, to testify as to bite marks discovered on [the victim’s] hip. Over the objection of the defense, [he] was qualified as an expert in the fields of forensic odontology and bite mark identification … [and] testified that on March 10, 2000, he was contacted by the district attorney’s office concerning a woman who had been sexually abused … [He] testified that upon his examination of [the victim’s] injuries that same day, he noticed swollen and bruised nipples, substantial trauma to the vaginal area and what appeared to be a bite mark on her right thigh. He immediately informed the district attorney’s office of the bite mark and asked for dental molds of any possible suspects. After he received the dental molds of [four individuals, he] returned to the hospital on March 15, 2000, to compare the molds to the actual bitemark. One of his testing procedures was to press the dental molds literally into [the living victim’s] skin. After numerous tests, [he testified that he] could not exclude Stubbs as being the person who caused the bite mark on [the victim] … [and] was able to state the other three molds did not match the bite mark.

The case became more interesting when the dentist testified [80] that he was also informed by the medical staff that [the victim] additionally suffered from head injuries. He took pictures of the injuries and informed Det. Jones of the newly discovered injuries. While … with Det. Jones, he was able to view the surveillance video tape from the night the [female suspects] checked into the Comfort Inn. [The dentist] testified that after numerous video enhancements, he was able to determine that Stubbs removed [the victim] from the toolbox and carried her

Case Law inside the motel room. [He] also noticed the latch on the toolbox was similar [in shape] to the injuries on [the victim’s] head and lower thigh. He measured the distance between the two latches and the distance between [her] injuries. Both distances were thirty-seven (37) inches apart. Using his assistants, [he] was able to determine that a woman of [the victim’s] size could be placed into the tool box and then removed by another woman. The defense called their own expert witness … to refute the claim of [the forensic dentist] that the mark on [the victim’s] hip was a bite mark. [The defense expert], a forensic pathologist, testified [the victim] could not have fit in the tool box. He also stated [that the victim] could not have sustained her head injuries from the tool box because the tool box was aluminum and the hinges do not allow the box to be closed with enough force. He did agree the thirty-seven inches coincided with the latches on the toolbox and [the victim’s] injuries. [The pathologist] also testified there were many objects, other than teeth, that could have left the appearance of the half moon or semicircle marks found on [the victim’s] hip, such as a flashlight or the heel of a shoe. He stated when he first saw the video of the bite mark, he did think it could be an animal bite, but that was before he realized [the forensic dentist] had pressed the dental mold into the skin to compare the mold to the mark. In order to preserve the actual mark, [the pathologist] testified he would have performed the test to compare the molds to the bite mark differently.

The defense argued that the forensic dentist’s testimony should have been excluded because it was clearly beyond his field of expertise … [contending] the opinion … regarding the teeth impressions of Stubbs was not an expert opinion … [Because] “he could not find enough details in the mark to give it his highest opinion as an expert.” Vance argues [the] testimony was prejudicial because it concluded a question of fact; he was not able to testify to a reasonable degree of certainty; and, it did not help the jury clearly resolve an issue of fact.

The defense also argued that, although the forensic odontologist was never qualified as an expert in video enhancement, he was allowed to offer testimony as to a videotape which he believed depicted [the victim] being carried out of Stubbs’s truck into the hotel. Vance contends that [the dental expert] was also allowed to offer lay opinion testimony regarding alleged cigarette burns on [the victim] by holding a cigarette next to the wounds to conclude they matched. Vance also strongly contends [the expert] tampered with evidence by taking a dental mold of Stubbs and pressing it against [the victim’s] leg and creating a bite mark that was not present before his procedure.

535

The state responded [81]: [T]he trial court did not abuse its discretion in accepting … or in allowing [him] to testify at trial. The State argues this Court has previously recognized odontology as an acceptable area of professional and forensic expertise. The State contends that [he] followed the proper procedures for bite mark testimony, that the appearance of bite marks was testified to by others before [he] was called to consult on the case, and that exhibits also clearly showed the evidence of bite marks on [the victim] prior to … conducting his test regarding the dental molds of Stubbs.

Furthermore, the defense pathologist “did agree that the marks on [the victim] resembled bite marks” [81]. The court ruled: With regard to the contention that [the forensic dentist] testified outside the area of his expertise, the State argues that the record shows this was not the basis of the objections made at trial; that the objection regarding the cigarettes was only to [his] testifying to “the history of cigarettes,” not to using a cigarette to point to alleged cigarette burns; that the objection regarding the surveillance tape photographs was only to [his] using the term “blow” as well as a Rule 403 objection; that the objection was not regarding the video enhancement showing a body being carried into the hotel room; and, that the Miss. R. Evid. 403 objection was repeated when [the victim herself] was brought in before the jury to demonstrate the distance between the injuries on her head and side.

Continuing on, the court also held that “[r]egarding the alleged tampering of evidence by [the forensic dentist], the State argues [he] clearly explained his procedure to the jury. Although [the pathologist] testified he would have used a different procedure, he did not testify that [the dentist] employed an improper medical or forensic procedure” [82]. The court concluded with two cautionary statements [83]: There is little consensus in the scientific community on the number of points which must match before any positive identification can be announced (citation omitted). Because the opinions concerning the methods of comparison employed in a particular case may differ, it is certainly open to defense counsel to attack the qualifications of the expert, the methods and data used to compare the bite marks to persons other than the defendant, and the factual and logical bases of the expert’s opinions. Also, where such expert testimony is allowed by the trial court, it should be open to the defendant to present evidence challenging the reliability

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of the field of bite-mark comparisons (citation omitted). Although Stubbs and Vance both objected to [the dentist] being qualified as an expert, they were each given the opportunity to challenge the reliability of the bite mark evidence as required.

Secondly, the court noted [84]: [T]he defense failed to object to [the dentist] testifying outside the area which he had been qualified as an expert except as to narcotics. The trial court found [his] testimony, including testimony regarding bite marks, [the victim’s] injuries, and video enhancement, to be relevant and more probative than prejudicial. Because of the extensive record before this Court, because of the trial court’s permitting extensive cross-examination of [the dentist] by defense counsel, and because the defense called its own expert … to rebut [the dentist’s] testimony, we cannot say that the trial court abused its discretion in admitting the testimony. … While, as noted above, this Court … made an affirmative statement that bite-mark identification is clearly admissible in our state trial courts, we in no way implied that [this dentist] was given carte blanche to testify to anything and everything he so desired. From our cases wherein [he] has been involved, he has primarily been recognized by this Court to have been appropriately declared by the trial courts to be an expert in the field of forensic odontology. This does not mean that [he] can indiscriminately offer so-called expert testimony in other areas in which he not even remotely meets the Miss. R. Evid. 702 criteria … A different record in this case could have brought about different results.

In a footnote to a Florida murder case, Ramirez v. Florida, 810 So.2d 836, FL (2001, rehearing denied), that was overturned (for the third time) on grounds other than the forensic dental evidence, the court alluded to dental testimony that bears on the case discussed previously. In the original 1983 trial of Ramirez, the “[s] tate presented the live testimony of … a dentist and consultant in forensic odontology … who testified that use of hard casts is generally accepted in the field as a method of analyzing wounds made in human tissue.” In Ramirez, the use of a knife mark identification “[f]or the first time in the history of the Florida courts” was ruled inadmissible [85].

29.10 Even Further beyond Linkage In Arizona v. Tankersly, 956 P.2d 486, AZ (1998), “a forensic odontologist testified it was ‘highly probable’ that defendant had bitten the victim’s left breast, and another said that his teeth ‘matched’ the bite marks”

[86]. In affirming the conviction, the court also noted the following testimony adduced at trial: “Finally, evidence presented at trial established that [an alternate suspect] had no teeth and that his dentures had been destroyed in a fire years before the murder. Expert testimony demonstrated that the bite marks found on the victim’s body could not have been made by someone without teeth or [by someone] with dentures” [87]. After a jogger was attacked and killed by dogs running loose from their owner’s property in the case North Carolina v. Powell, 446 S.E.2d 26, NC (1994), the court on appeal accepted the testimony of “[a] forensic odontologist … that dental impressions taken from Bruno and Woody [the ‘accused’ dogs] were compatible with some of the lacerations in the wounds pictured in scale photographs of [the victim’s] body” [88]. There have since been numerous animal bite cases litigated, but no others were discovered in the appellate records. Fingernails linked to scratch marks found on the back of the neck of a murder victim take center stage in the case of Pennsylvania v. Graves, 456 A.2d 561, PA Super. (1983). Three forensic dentists and a criminalist participated for the state. The primary forensic dental investigator testified that he [89] made an impression or cast of one of those scratch marks, using a compound of the same general type as dentists use in making impressions of teeth. He then compared that impression with an impression made from the nail on appellant’s fourth (left) finger, using among other things, a comparison microscope. On the basis of these comparisons he testified that: “it was highly likely that the nail of the fourth finger, left hand, of Bennie Graves had made the mark in the neck of [the victim].”

The second dentist then [90] based upon his examination of finger nail clippings, photographs, slides and [the] impression, testified to a “fractured edge” on the impression of appellant’s finger nail, and to his opinion that “it is highly probable” that appellant’s finger nails made the mark on the neck of [the victim]; and that it was “very unlikely” that “some person other than Bennie Graves … made these marks.”

The third dentist [91], utilizing photographs and slides of the decedent’s body and finger nail clippings of appellant, testified to his opinion “that the left-little finger and the left-ring finger (of appellant) were consistent with the injury patterns shown in the photographs” of the deceased; that there was “a high degree of certainty in this case,” and finally that there was “[a]n extremely high degree

Case Law of probability to the point of practical impossibility of finding two other nails on two fingers adjacent to each other that would make these marks.”

Interestingly, the criminalist in Graves was much less strident, testifying that he [92] characteriz[ed] a fingernail mark in the skin as “a tool mark,” based upon an examination of the impression made by [the first forensic dentist], and of a wax impression of appellant’s left little finger, again using the comparison microscope concluded that: “the fingernail impression as seen on the wax mold had the same class characteristics as the fingernail.” He testified further that “there is probably a fair degree of probability that this nail or any nail of this shape made this kind of mark …” Over appellant’s objection, he was later permitted to say that “this would be one (case) of high probability,” although the nail could not be characterized as “unique.”

The original conviction was affirmed. In the case of Washington v. Oklahoma, 836 P.2d 673, OK Crim. App. (1992), one judge dissented from the majority, holding that failure to provide funding for defense experts is harmless error. In his dissent, he outlined the basis for the evidence offered by the state’s forensic dental expert [93]: Regarding the first expert, the State relied upon the testimony of a forensic odontologist to establish that appellant was the perpetrator of the bitemark found on the murder victim. The State’s expert testified that he used two types of analyses to identify appellant as the assailant: bitemark/dentition comparison and a comparison of microorganisms found in the wound and in appellant’s mouth. The doctor placed primary identification emphasis on the microorganism “aspergillus” being present in both the bitemark and in appellant’s mouth. At trial, the doctor testified that aspergillus would be found in the mouths of only “one in a billion people.” Although the doctor claimed that his tests were “accepted,” he admitted that he was aware of no other persons who either used or advocated the use of microbiological analysis in bitemark comparisons. I agree with the trial court’s conclusion that without an expert odontologist, the defense was unable to determine the reliability of the comparison techniques used by the State’s expert or the accuracy of the conclusions he reached.

The author would also concur with the dissenting judge. Another voyage into the fringes of forensic odontology would appear to have occurred in the case Henry v. Horn, 218 F.Supp.2d 671, E.D.PA (2002), in which a convicted murderer sought relief in the federal courts, claiming that

537 he was denied a fair trial and due process by the prosecution’s presentation of false, inadmissible, unreliable and misleading testimony during both the guilt and penalty phases of trial. Specifically, he claims that the testimony of … [a forensic dentist] that he could determine the mental state of the attacker from a bite mark, was false, unreliable and misleading. Henry alleges that the prosecution either knew or should have known that this testimony was false and that it knowingly utilized this false testimony to obtain both the conviction of first-degree murder and the resulting death sentence.

The court denied the requested relief, stating [94]: [T]he present case, however, does not involve the knowing use of false evidence … simply because Henry’s experts disagree with the Commonwealth’s experts does not mean that the Commonwealth knowingly presented false evidence in violation of Henry’s due process rights. The evidence before the Pennsylvania Supreme Court when it decided this claim included no affidavits from either the prosecutor or the witnesses whose testimony was challenged. (“The foundation for Henry’s claim that the Commonwealth presented false evidence is the testimony of his experts … at the … hearing. These experts disputed the validity of the scientific theories on which [the forensic odontologist] based [his] testimony.”) Henry simply presented opposing experts who criticized government’s expert witnesses and the bases of their testimony. As this evidence falls far short of the affidavits of false testimony that the Supreme Court has consistently required for such claims, the Pennsylvania Supreme Court did not unreasonably [deny] him relief.

29.11 Expert for the Prosecution but Not the Defense A number of appeals have arisen discussing the issue of the defendant in a criminal case not having access to a forensic dental expert to analyze and possibly controvert the testimony and opinion of the state’s expert. Perhaps the most well known of these cases is Wilhoit v. Oklahoma, 816 P.2d 545, OK Crim. App. (1991), in which the central issue was the allegation of ineffective assistance by counsel during trial. As a basis for ruling that defendant Wilhoit had not received adequate representation, the court stated in its order demanding a new trial [95]: [T]he Oklahoma Bar Association had found counsel’s ability to function as a lawyer was noticeably impaired by alcohol during the time he was representing appellant. Trial counsel even stated in an affidavit that there was no strategic reason for his not pursuing

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the bite-mark evidence nor for not using a bite-mark expert. This omission is even less excusable in light of the fact that the Wilhoit family had hired a forensic odontologist who was available to examine the bitemark evidence. Judge Pearman found that because of his failure to investigate the bite-mark evidence, appellant’s counsel was deficient and that there is a reasonable probability that the result of the trial would have been different had the defense used an expert. The omission of this evidence cannot be considered a strategic defense tactic.

In a case that arose in the Eastern District of Louisiana, Jackson v. Day, 1996 U.S. Dist. LEXIS 7001, a federal district judge granted a writ of habeas corpus [96], stating that counsel’s failure to move the trial court for a declaration of indigency and funds to retain an odontologist was not a strategic decision but rather a legal mistake. Despite the plethora of decisions on this topic in the 1980’s, [the defense counsel] actually testified that it was not until 1992 that the “Supreme Court [held] that a person has a constitutional right to have his expert witnesses funded if he was indigent” (Transcript, p. 68). An odontologist was a “crucial” safeguard to W. Jackson’s “ability to marshal his defense and, thus, ensure an accurate result.” Therefore, all reasonable trial strategy in W. Jackson’s case as testified to by [counsel] mandated the retention, or at least attempted retention, of an odontologist.

However, in an unpublished decision, Jackson v. Day, 121 F.3d 705 (1997), the U.S. Fifth Circuit Court of Appeals reversed, finding “no constitutional error,” citing overwhelming evidence against the defendant, and further commenting that had the defense hired a forensic odontologist “that there is no reasonable probability that ‘a battle of the experts’ would have been sufficient to raise a reasonable doubt [as to guilt]” [97]. In 1998 the U.S. Supreme Court at 523 U.S. 1006 refused to grant certiorari. In 2006 the local district attorney declined to reopen the case after Mr. Jackson had been granted a new trial based on DNA evidence, even though the judge noted that “the victim-witness’s testimony was unshakable” and was the primary basis for the original conviction. The newly discovered DNA evidence did not automatically exclude Mr. Jackson [98]. In Missouri v. Fleer, 851 S.W.2d 582, MO App. (1993), the prosecution offered testimony from a forensic dentist to refute a claim concerning a possible bitemark on the victim’s genitals. Although the primary issue on appeal was the late entry of the forensic dentist as a witness, the court’s holding does address the issue of the defense not rebutting the opinion with an independent

forensic dental opinion. The state’s forensic odontologist [99] stated that marks found on Howlett’s penis were not caused by human teeth. Fleer argues that this testimony was fundamentally unfair to him since he intended to argue that: (1) Howlett murdered Price after Price resisted his sexual advances, as evidenced by the clenched teeth marks on Howlett’s penis; and (2) Howlett murdered Tyler because Tyler could have identified him. Although Fleer did not waive his objection to [the state’s expert’s] testimony, he failed to show that the State intended surprise or acted deceptively or in bad faith with intention to disadvantage him. Moreover, Fleer has failed to show that he was surprised or that [the complained of] testimony might not have been contemplated. Since Fleer intended to argue that the marks on Howlett’s penis were caused by Price’s teeth, Fleer could expect that the State would attempt to foreclose this theory by presenting evidence which would negate this hypothesis. Moreover, we are unable to conclude that the admission of [the dental] testimony resulted in fundamental unfairness to Fleer, for four reasons. First, defense counsel opened the door to rebuttal testimony regarding the marks on Howlett’s penis when he asked [the medical examiner]: (1) whether the marks on Howlett’s penis could be consistent with any number of things; (2) whether the marks were applied when Howlett had an erection; and (3) whether he had any means of telling what caused Howlett’s wound. Second, defense counsel, apparently, did not depose [the state’s forensic dental expert] before trial. Third, defense counsel did not find a rebuttal witness, although they had thirteen days to do so. Fourth, defense counsel did not seek a continuance after having been notified that [the forensic dentist] would testify. For these reasons … [his claim] is denied.

29.12 Testing the Expert On occasion, courts have devised their own method of qualifying a would-be expert. In the 1983 case, Louisiana v. Stokes, 433 So.2d 96, LA (1983) [100], the trial judge responded to the prosecution’s request to compel the defendant to submit to the taking of an impression of his upper and lower teeth … in order to compare the defendant’s teeth with the marks found on the victim. After a hearing on the matter, the trial court granted the state’s motion. Out of fairness to the defendant, however, the trial court structured the test as follows: The teeth impression[s] of five different persons would be sent to the state’s expert for analysis. Four of the impressions would be from male Caucasians within ten years of the defendant’s age. The defense and state

Case Law would each select two of the persons giving the impressions. The fifth impression sample would be that of the defendant. The identity of the five persons submitting impressions would not be disclosed to the expert. This would insure that the test would be conducted in a nonsuggestive manner. The five impressions were made and sent to the state’s expert [dentist] … for comparison with photographs taken of the bite-marks on the victim. [The expert’s report] concludes that there was not enough evidence to positively identify the suspect. He also states that he could not exclude any of the persons submitting impressions from consideration as having produced the bite-marks on the victim. A copy of this report was presented by the prosecutor to the defense counsel on the day of trial … [D]efense counsel notified the trial court that it wanted to introduce [the] report into evidence during the trial. The trial judge stated that he had no intention of allowing the report into evidence without the testimony of [the expert] when the latter was available for subpoena … After the state rested its case, the defendant again sought to introduce the report … without the testimony of the doctor. He argued that the report should be allowed in evidence under the business records exception to the hearsay rule. He also contended that he would be prejudiced by the fact that he would be required to call [the expert] on direct examination [rather than have the ability to cross-examine him]. The trial judge refused to admit the report into evidence due to the fact that [the doctor] was available for testimony … [The] document itself may not be reliable. Without the testimony of the doctor, it would be difficult to assess the validity of the test upon which the opinions of the doctor expressed in the report were based. Furthermore, we find no merit to the defendant’s contention that he would be prejudiced by calling [the expert] on direct. In effect, the defendant is willing to vouch for the credibility of the doctor’s conclusions included in his report. Yet, he refuses to vouch for the credibility of the doctor’s testimony which would explain how he arrived at his conclusions.

29.13 Conclusions As stated in the beginning of this chapter, not all cases involving bitemark evidence are available for review and comment. The law on any given subject, bitemark evidence included, is constantly evolving from case to case and from state to state as the scientific underpinnings of forensic odontology gain a firmer (hopefully, not a weaker) foundation and as the defense bar hones its skills in contesting the evidence. As this chapter is being written, new cases in the emerging field of expert witness liability, the impact of DNA and other tissue/ cell typing, and the very state of “identification science”

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itself are being litigated in numerous courts throughout the United States and other nations. It would be presumptuous of the author as well as the reader to expect that any treatise could provide a deep and broad enough background to navigate the legal waters of forensic odontology safely. Constant study of the case law, the methodology, and the parallel forensic disciplines is required. Perhaps the single best piece of advice that could be gleaned from the case law is to look to the past to see where the future lies. Rereading the testimony of some of the pioneers in the field reveals their abiding commitment to forensic odontology and their great reluctance to overstep the bounds of their expertise. This is particularly relevant in light of the report from the National Academy of Sciences, Strengthening Forensic Science in the United States: A Path Forward (2009) [101], which states that there is continuing dispute over the value and validity of comparing and identifying bitemarks. Among other issues (and other branches of forensic science), the report highlights the lack of both inter- and intrarater reliability in bite analysis. The report calls for more study and research in areas such as the uniqueness of each individual’s dentition; the ability of the dentition to transfer reliably to, and of human skin to reproduce, bite patterns; the role that distortion plays; and establishment of a standard threshold of evidentiary value. This author is concerned that names such as Krone—the 100th person whose wrongful conviction, largely based on bitemark testimony, was proven by the Innocence Project—or Kennedy Brewer—the 213th exoneration in whose conviction the testimony of a forensic dentist provided the only physical link— may become better known in forensic circles than those of the many cases cited here. Without constant attention to the foundations and continual improvement in the underlying science of odontology, it may come to pass: No fewer than four law review articles in 2009 alone took bitemark analysis to task. The time is ripe for forensic dentistry to put its own house in order—legally and scientifically.

References 1. Moradi-Shalal v. Fireman’s Fund Ins. Companies, 46 Cal.3d 287 (1988) at page 296. 2. United States v. Washington, 872 F.2d 874 (9th Cir. 1989) at page 880. 3. Pitluck, H. M., and R. E. Barsley, 2010. Appendix 1: U.S. federal and state court cases of interest in forensic odontology. In Forensic dentistry, 2nd ed. D. R. Senn and P. G. Stimson, Eds. Boca Raton, FL: Taylor & Francis, pp. 417–421.

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4. Illinois v. Milone, 356 N.E.2d 1350, IL App. (1976) at page 1354. 5. Illinois v. Milone, 356 N.E.2d 1350, IL App. (1976) at page 1354. 6. Seivewright v. State, 7 P.3d 24, WY (2000) at page 30. 7. Giannelli, P. C., and E. J. Imwinkelried. 1999. Scientific evidence, 3rd ed., 583. Miarnisburg, OH: Lexis Law Publishing. 8. Illinois v. Dace, 506 N.E.2d 332, IL App. (1987) beginning at page 335. 9. People v. Mostrong, 2003 Cal App. Unpub. LEXIS 1179 at page 4. 10. People v. Mostrong, 2003 Cal App. Unpub. LEXIS 1179 beginning at page 4. 11. R. V. Stillman, 37 W.C.B. (2d) 215 (1998) at page 2 in the printout and page 4 in the original. 12. Vermont v. Howe, 386 A.2d 1125, VT (1978) at page 1131. 13. Winston and Davis v. Lee, 470 U.S. 753 (1985) at page 767. 14. Doyle v. State, 263 S.W.2d 779, TX App (1954) at page 779. 15. Mobley v. Georgia, 441 S.E.2d 780, GA App (1994) at page 782. 16. Hoskins v. McBride, 2000 U.S. Appeals LEXIS 27398, 7th Cir. (cert. denied) at page 2. 17. Louisiana v. Martin, 645 So.2d 190, 204, LA (1994, rehearing denied) in J. Calagero’s concurrence at page 204. This case was later upheld at Martin v. Cain, 246 F.3d 471, 5th Cir (2001). 18. Rhode Island v. Adams, 481 A.2d 718, RI (1984) beginning at page 727. 19. Rhode Island v. Adams, 481 A.2d 718, RI (1984) at page 727. 20. Harris v. Arkansas, 1992 Ark. App. 728 LEXIS (1992) beginning at page 4. 21. Draper v. Adams, 2000 U.S. App. Lexis 11826, 6th Cir (2000) at page 3. 22. Louisiana v. Vital, 505 So.2d 1006, LA App. (1987) beginning at page 1007. 23. Illinois v. Queen, 474 N.E.2d 786, IL App. (1985 rehearing denied) beginning at page 787. 24. Wisconsin v. Stinson, 397 N.W.2d 136, Wisc. App. (1986) beginning at page 141. 25. Wisconsin v. Stinson, 397 N.W.2d 136, Wisc. App. (1986) at page 142. 26. Mills, S. 2009. Wisconsin man’s conviction voided. Chicago Tribune, Jan. 31. 27. Vermont v. Howe, 386 A.2d 1125, VT (1978) at page 1132. 28. Rhode Island v. Adams, 481 A.2d 718, RI (1984) at page 727. 29. Arizona v. Garrison, 585 P.2d 563, AZ (1978) at page 566. 30. People v. Slone, 143 Cal. Rptr. 61, Cal. App. (1978) at page 67. 31. People v. Slone, 143 Cal. Rptr. 61, Cal. App. (1978) at page 68.

32. People v. Slone, 143 Cal. Rptr. 61, Cal. App. (1978) at page 70. 33. State v. Duncan, 802 So.2d 533, LA (2001, cert. denied) at page 553. 34. State v. Duncan, 802 So.2d 533, LA (2001, cert. denied) at page 553 including note 20. 35. State v. Duncan, 802 So.2d 533, LA (2001, cert. denied) beginning at page 554. 36. State v. Duncan, 802 So.2d 533, LA (2001, cert. denied) beginning at page 557 including note 25. 37. Kinney v. State of Arkansas, 868 S.W.2d 463, AR (1994) at page 465. 38. Washington v. Kendrick, 736 P.2d 1079, Wash. App. (1987) at page 1082. 39. Illinois v. Milone, 356 N.E.2d 1350, Ill App (1976) beginning at page 1355. 40. Illinois v. Milone, 356 N.E.2d 1350, Ill App (1976) at page 1356. 41. Illinois v. Milone, 356 N.E.2d 1350, Ill App (1976) at page 1356. 42. Illinois v. Milone, 356 N.E.2d 1350, Ill App (1976) at page 1356. 43. Illinois v. Milone, 356 N.E.2d 1350, Ill App (1976) at page 1357. 44. Illinois v. Milone, 356 N.E.2d 1350, Ill App (1976) beginning at page 1356. 45. People v. Mattox, 237 N.E.2d 845, Ill. App. (1968) at page 846. 46. Illinois v. Milone, 356 N.E.2d 1350, Ill App (1976) at page 1358. 47. Illinois v. Milone, 356 N.E.2d 1350, Ill App (1976) at page 1360. 48. Milone v. Camp, 22 F.2d 693, 2nd Cir. (1994, cert. denied) beginning at page 700. 49. Niehaus v. Indiana, 359 N.E.2d 513, IN (1977) at page 516. 50. Kansas v. Peoples, 605 P.2d 135, KS (1980) at page 139. 51. Kansas v. Peoples, 605 P.2d 135, KS (1980) beginning at page 139. 52. Kansas v. Peoples, 605 P.2d 135, KS (1980) at page 140. 53. Commonwealth v. Cifizzari, 492 N.E.2d 357, MA (1986) at page 360. 54. Commonwealth v. Cifizzari, 492 N.E.2d 357, MA (1986) at page 363. 55. Commonwealth v. Cifizzari, 492 N.E.2d 357, MA (1986) beginning at page 363. 56. Louisiana v. Wommack, 770 So.2d 365, LA App. (2000) beginning at page 373. 57. Louisiana v. Wommack, 770 So.2d 365, LA App. (2000) at page 374. 58. Louisiana v. Wommack, 770 So.2d 365, LA App. (2000) beginning at page 75. 59. Louisiana v. Wommack, 770 So.2d 365, LA App. (2000) at page 376. 60. Seivewright v. State, 7 P.3d 24, WY (2000) beginning at page 30. 61. Illinois v. Holmes, 601 N.E.2d 985, IL App (1992) at page 991.

Case Law 62. Illinois v. Holmes, 601 N.E.2d 985, IL App (1992) beginning at page 992. 63. Illinois v. Holmes, 601 N.E.2d 985, IL App (1992) beginning at page 993. 64. Spence v. Scott, 80 F.3d 989, 5th Cir. (1996, cert. denied) at page 1000. 65. Spence v. Scott, 80 F.3d 989, 5th Cir. (1996, cert. denied) at page 1000 note 8. 66. Spence v. Scott, 80 F.3d 989, 5th Cir. (1996, cert. denied) at page 1000. 67. Spence v. Scott, 80 F.3d 989, 5th Cir. (1996, cert. denied) at page 1000. 68. Monk v. Zelez, 901 F.2d 885, 10th Cir. (1990). 69. U.S. v. Martin, 9 M.J. 731, USNCMR (1978) at page 738. 70. Tuggle v. Nederland, 79 F.3d 1386, 4th Cir. (1996) beginning at page 1388. 71. Tuggle v. Nederland, 79 F.3d 1386, 4th Cir. (1996) beginning at page 1393. 72. Hoskins v. McBride, 2000 U.S. Appeals LEXIS 27398 (cert. denied) at page 2. 73. U.S. v. Martin, 9 M.J. 731, USNCMR (1978) at page 738. 74. Gilliam v. Florida, 817 So.2d 768, FL (2002, rehearing denied) at page 779. 75. U.S.A. v. Kills in Water, 293 F.3d 432, 8th Cir (2002) beginning at page 434. 76. U.S.A. v. Kills in Water, 293 F.3d 432, 8th Cir (2002) at page 436 note 5. 77. People v. Cumbee, Rule 23 Order, Nov 15, 1995, 2nd District Appellate Court, appeal from Circuit Court McHenry County, Illinois, no. 92-CF-676. 78. Cumbee v. Nygren, 2000 U.S. App LEXIS 3148 (7th Cir., 2000) at page 1. 79. Stubbs and Vance v. Mississippi, 845 So.2d 656, MS (2003, rehearings denied) beginning at page 661. 80. Stubbs and Vance v. Mississippi, 845 So.2d 656, MS (2003, rehearings denied) beginning at page 662. 81. Stubbs and Vance v. Mississippi, 845 So.2d 656, MS (2003, rehearings denied) at page 668. 82. Stubbs and Vance v. Mississippi, 845 So.2d 656, MS (2003, rehearings denied) beginning at page 668.

541 83. Stubbs and Vance v. Mississippi, 845 So.2d 656, MS (2003, rehearings denied) at page 669. 84. Stubbs and Vance v. Mississippi, 845 So.2d 656, MS (2003, rehearings denied) at page 670. 85. Ramirez v. Florida, 810 So.2d 836, FL (2001, rehearing denied) at page 848 note 31. 86. Arizona v. Tankersly, 956 P.2d 486, AZ (1998) at page 489. 87. Arizona v. Tankersly, 956 P.2d 486, AZ (1998) at page 497. 88. North Carolina v. Powell, 446 S.E.2d 26, NC (1994) beginning at page 27. 89. Pennsylvania v. Graves, 456 A.2d 561, PA Super. (1983) at page 565. 90. Pennsylvania v. Graves, 456 A.2d 561, PA Super. (1983) beginning at page 565. 91. Pennsylvania v. Graves, 456 A.2d 561, PA Super. (1983) at page 566. 92. Pennsylvania v. Graves, 456 A.2d 561, PA Super. (1983) at page 565. 93. Washington v. Oklahoma, 836 P.2d 673, OK Crim. App. (1992) Judge Lumpkin in dissent at page 678. 94. Henry v. Horn, 218 F.Supp.2d 671, E.D.PA (2002) beginning at page 699. 95. Wilhoit v. Oklahoma, 816 P.2d 545, OK Crim. App. (1991) at page 546. 96. Jackson v. Day, 1996 U.S. Dist. LEXIS 7001, E.D.LA beginning at page 8. 97. Jackson v. Day, 121 F.3d 705 (1997) unpublished opinion 96-30563 beginning at page 6. 98. Purpura, P. 2006. Long nightmare ending for wrongly convicted man; DNA brings dismissal of case after 16 years. Times-Picayune, June 5. 99. Missouri v. Fleer, 851 S.W.2d 582, MO App. (1993) beginning at page 591. 100. Louisiana v. Stokes, 433 So.2d 96, LA (1983) beginning at page 102. 101. National Academy of Science. 2009. Forensic science in the United States: a path forward. Washington, DC: National Academy Press.

Contracting with the Expert Witness Roger D. Metcalf

30

Contents 30.1 Forming a Valid Contract 30.2 Oral versus Written Contracts 30.3 The Offer 30.4 The Acceptance 30.5 Consideration 30.6 Defenses to a Valid Contract 30.7 Remedies for Breach 30.8 Typical Parts of a Contract 30.9 Sample Contract Consultant Agreement References

543 544 545 546 548 548 551 556 558 559 560

Caveat: The following information is not intended in any way to be legal advice, nor a substitute for consultation with a competent attorney. It is intended only to be a general guide to inform and assist the odontologist, and the odontologist should not rely on the following to replace the advice of an attorney. This material does not necessarily reflect the opinion of the Tarrant County Medical Examiner’s District.

30.1â•…Forming a Valid Contract A contract is simply an agreement—a particular type of agreement a court will enforce if necessary. People and businesses make agreements constantly, but not all are contracts. What is essential for an agreement to become a contract? A contractual agreement is a mutual agreement based on an exchange of something of value from one party for something of value from the other party so that each is satisfied he or she is better off in some way. Black’s Law Dictionary defines a contract as: “[a]n agreement between two or more parties creating obligations that are enforceable or otherwise recognizable at law” [1]. Why are some agreements “enforceable at law” and what is the meaning of “enforceable at law”? There is apparently something more than just a simple agreement needed between the parties in order to make an enforceable contract, and indeed there is more required for the agreement to be legally binding on both parties. Contracts can become very important when the exchange of items of value does not take place immediately upon reaching an agreement but, instead, the agreed-upon exchange is deferred until sometime in the future.

One form of contract of interest to odontologists, where a future exchange of things of value is involved, is sometimes called a “contract for personal services.” The type of contract of particular concern is frequently an arrangement where one party (the odontologist) agrees to provide some sort of expert professional service to the other party (most likely a medical examiner or coroner, prosecutor, plaintiff, or defendant). The essence of the transaction is that, in exchange for performing certain services, the odontologist will receive payment of a fee. A contract is important for these parties, though, because the actual situation is, to be more precise, the odontologist receives an offer of employment from the coroner and the coroner’s promise of payment in the future, on the condition that the requested services will have been performed. In turn, the odontologist accepts the coroner’s offer and promise and, in consideration of the agreement, gives a return promise to go to the morgue at some time in the future to examine the decedent. Problems arise when contracting parties for one reason or another do not keep the promises they made. Suppose an attorney comes to a dentist’s office one day and says, “How about if we make a deal—all the legal services you need for all the dental services I need?” and the dentist says, “Done.” Nothing of real value has been exchanged at this point in the transaction; the proposed services are yet to be performed at some indefinite time in the future. All that has been exchanged to this point are vague promises. The terms of this agreement are hazy, almost nonexistent. If the dentist reconsiders the deal and does not live up to what the attorney thought the dentist had promised to do,

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can the attorney somehow force the dentist to comply with their agreement and place all the dental restorations the attorney needs? Could the attorney sue the dentist for money? To begin our analysis of the problem, we ask the threshold question: Did the parties have an agreement that was a valid contract? The traditional requirements for a contract in jurisdictions that follow English common-law customs are: offer, acceptance, and consideration. In the absence of just one of these necessary elements, there simply is no contract between the parties. But, before these terms are considered, do the parties need to go to all the trouble of writing down everything in their agreement or is a simple verbal agreement satisfactory?

30.2 Oral versus Written Contracts Valid contracts may be made either orally or in writing. If a forensic dentist has worked with a certain attorney-client several times in the past and they have a good working relationship, the dentist may be comfortable with only a verbal arrangement and find that a written contract is not necessary in every case. But the problem with oral contracts is that they depend fully on the recollection of the parties involved. Parties may forget important details, either accidentally or on purpose, and it might be difficult to prove an oral agreement was made. A party may recall and interpret certain provisions of the contract more strongly in his or her own favor than was mutually agreed to by both parties. For this reason, the English Statute of Frauds was enacted in 1676 [2]. This statute, intended to prevent fraud and perjury, required certain types of contracts to be in written form and signed by the “party to be charged” if they were to be enforceable at law. The party to be charged is the party against whom the contract would be enforced. For example, if forensic dentist Dr. Ivory made a contract with a coroner and a lawsuit became necessary for Ivory to recover the fee, it really would not matter much to Dr. Ivory’s case whether or not Dr. Ivory had signed the contract himself. After all, since Dr. Ivory has now asked for the contract to be enforced, it would be fairly clear he has accepted the terms of the agreement. But it would be very important to Dr. Ivory’s case whether or not the other party, the coroner, had signed the contract. If Dr. Ivory had not made sure the coroner signed the agreement, the coroner might claim as a defense that the parties simply do not have a contract at all. Signing the contract is an overt and explicit indication of acceptance. If Dr. Ivory must sue the coroner for

breach of contract, then the party to be charged would be the coroner. Similarly, for protection in case of the odontologist’s default, the coroner would want to be certain Dr. Ivory signed the contract, as well. (Please note that all names used in these hypothetical examples are fictitious. All situations presented are also fictitious, unless otherwise indicated.) Modern statutes of frauds generally require a written, signed contract for the sale of land, the sale of goods valued at more than $500, an act that cannot be performed or completed within 1 year of making the contract (such as a long-term lease), a contract for an executor to answer for a decedent’s debt, a contract to guarantee a debt or duty of another, or a contract made in consideration of marriage informally known as a “pre-nup.” Each U.S. state has its own particular version of a statute of frauds, but the Constitution of the United States and these state constitutions otherwise guarantee wide latitude to individuals who wish to enter into a contract. For example, the U.S. Constitution assures us that “[n]o state shall … pass any … law impairing the obligation of contracts” [3]. A typical example of a state constitution, the constitution of the state of Texas, also says that “[n]o … law impairing the obligation of contracts shall be made” [4]. A contract specifically for the sale of goods between merchants, on the other hand, is a tightly regulated and complex subject that falls under the rules of the Uniform Commercial Code (U.C.C.) The U.C.C. expressly does not apply to personal services contracts, such as a contract for expert witness services made between an odontologist and a coroner, and is of no further concern here. A writing can be very informal and still satisfy the statute of frauds; for example, a hastily scribbled handwritten note on a napkin might suffice to meet requirements of the statute of frauds. Private parties and businesses in many societies retain great freedom to contract in order to promote commerce, so the form and content of contracts are generally subject to only a few common-law and statutory constraints. For example, among the requirements for a valid contract in common-law jurisdictions are that the parties must be of age and mentally competent to make an agreement; the parties cannot make an enforceable agreement to commit an illegal act or acts; the parties must freely agree to the terms of the contract, and thus one party may not be forced to sign the contract against his or her will (i.e., under duress); and—a specific example of some interest to forensic dentists—an expert witness may not make a valid contract to perform services and provide testimony on a contingency-fee basis in a criminal case.

Contracting with the Expert Witness

That is, the amount of the expert’s fee or even whether the expert is paid at all may not depend on whether the defendant is found guilty or not guilty in a criminal case, nor depend on the amount of a potential award in a civil case. A contingency fee arrangement might tempt an unethical expert to state his opinion more strongly than is warranted in order to insure he would receive payment from his client, and such an arrangement is considered to be against public policy. An additional point of interest to practicing dentists, forensic or otherwise, is that an enforceable agreement is not made where the dentist induces a patient, or a forensic-services client, to “contract away” her right to sue the dentist for malpractice. For example, a valid agreement is not formed if Dr. Silver requires his patients to sign a boilerplate (preprinted) form that has buried in it somewhere among the fine print a clever statement to the effect that “I, Paula Patient, agree never to sue Dr. Silver for anything whatsoever.” Further, a valid contract is not made if a dentist induces a patient to sign an agreement for, or waive the dentist’s liability for, treatment the dentist knows, or should know, is below the standard of care. In other words, a patient cannot consent to malpractice. So, while it certainly would be possible for the odontologist to work for a client based on only an oral contract, the better situation would be to work under the terms of a clearly written contract. Most practitioners have probably heard the trite, old colloquialism that “an oral contract is not worth the paper it is written on” and, while an oral contract can be perfectly valid and enforceable, there is an element of truth in this saying. The advantage of a well-reasoned, clearly written contract is that the terms are in black and white on paper for all to see and the content does not depend on the parties’ memories; if the parties did eventually find themselves in court with their contract in dispute, the judge would have something tangible to read and interpret. This is the preferable situation for all involved because the court could then construe the contract as per only the written content found within the “four corners” of the pages of the contract. The judge would not have to entertain and interpret other evidence (“parol evidence”—extrinsic evidence, usually oral) about the agreement, subject to all the vagaries discussed, except in limited circumstances. As an analogy, the judge would not be put in the untenable position of having to act as a referee in a game where the rules of the game are unknown. (And always remember the first rule of going into any court: Do not aggravate the judge.) It is important to realize that many of the standard rules regarding contracts are default rules—that is, the rules the court will apply in the absence of some

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other arrangement agreed to by the parties. Parties can often “contract around” many of the traditional rules if they wish—again, because common-law jurisdictions favor allowing parties much freedom in construction of their contracts. For example, the party that wins a lawsuit is usually not allowed to recover from the losing party the attorney’s fees the winner paid for legal services. A simple provision in a contract, however, can provide that if a lawsuit becomes necessary between the parties, the losing side will pay the attorney’s fees of the prevailing side. But if the contract does not address some disputed point, the court will merely apply the default rule, and the parties may find this interpretation and ruling favorable or they may not. A definite advantage in having a competent attorney draft an agreement is that the attorney is familiar with typical pitfalls that arise in contract situations and will advise the unwary odontologist how to address and avoid these potential problems. The attorney will know when the default rules are satisfactory for some situation and when there is need to contract around the default rules. The attorney can point out ambiguities and terms that are not clear and even jargon that might have imposed an obligation the odontologist did not realize he was going to accept. If the odontologist is considering performing expert services for an attorney, whether a prosecutor or plaintiff’s attorney or defendant’s attorney, and that attorney wrote the contract being assessed, it would be very wise for the odontologist to have his own attorney—an attorney with only the odontologist’s best interest in mind—review any agreement before the odontologist signs it. Dentists, among all professionals, are probably the most aware of the value of practicing prevention. This concept fully applies to contractual situations as well. Therefore, to avoid misunderstandings and help prevent possible litigation over an agreement, though the applicable statute of frauds may not require a signed document for an odontologist and coroner, nonetheless, always get it in writing! Have a competent attorney review the contract before signing it!

30.3 The Offer A typical call to an odontologist from a coroner might go something along the lines of “Dr. White, I’d like for you to come by the morgue and examine a decedent. I think there may be a bitemark on the deceased.” Dr. White might reply, “Fine, I’ll be right over.” The parties may have some sort of an agreement here, but not a legally enforceable agreement. This agreement has not yet become a contract. No specific, explicit offer of

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employment has been made. Black’s Law Dictionary says that an offer is a “promise to do or refrain from doing some specified thing in the future; a display of willingness to enter into a contract on specified terms, made in a way that would lead a reasonable person to understand that an acceptance, having been sought, will result in a binding contract” [1]. The offer must be specific and definite in order to have an enforceable contract; the hallmarks of a good contract are clarity, preciseness, and thoroughness. The parties should be able to distinguish whether or not they are in preliminary negotiations or if a true offer has been made. The example of “I’d like for you to come by the morgue and examine a decedent. I think there may be a bitemark on the deceased” is fairly nebulous as far as terms of employment are concerned. The court would have to make assumptions and inferences in order to determine the actual intent of the coroner, and judges do not like being put on the spot of having to guess at just exactly what people really meant when they made a hasty agreement. After all, although it was not said in the preceding example, the coroner might have been thinking, “I’d like for you to come by the morgue and examine a decedent. I think there might be a bitemark on the deceased and, if you find that one exists, I’m going to wait and call Dr. Smith to do the analysis when he gets back from vacation.” It would be impossible for a judge to determine whether or not the coroner was really thinking that. It would be much better for contract purposes to have a clear and explicit written offer such as, “I am offering you the job of examining decedent number 1234 today and, if you find there is a bitemark on the deceased’s body, then performing a bitemark analysis, all work at the rate of $100 per hour.” Contracts drafted in clear and precise language do not wind up being litigated as much as those that are ambiguous. Again, judges do not like having to interpret ambiguities in order to resolve a dispute that could have been avoided by a clear statement of terms. The author’s favorite example of ambiguous terms is one used in the introductory contracts course taught by Judge Joe Spurlock, II, at the author’s law school. Suppose a Texas rancher has a field with a dozen horses in it. Some of the horses are red, some are white, and two are red and white. A city fella drives by the field, sees the beautiful horses, and tells the rancher, “I’ll give you $10,000 for your red and white horses.” The Texan says, “Done” and delivers two red and white horses to the city fella. “Wait a minute,” city fella says, “I bought all of your red and white horses—all 12 of them.” And the rancher replies, “Well, this is all of my red and white horses—both of ‘em. Some of the others are red and

some of the others are white, but only these two are red and white!” Is the meaning of the simple phrase “red and white” crystal clear? Not always.

30.4 The Acceptance An acceptance is “[a]n agreement, either by express act or implication from conduct, to the terms of an offer so that a binding contract is formed. If an acceptance modifies the terms or adds new ones, it generally operates as a counteroffer,” according to Black’s [1]. The simplest response to an offer would be the reply, “No, thanks.” This constitutes a frank rejection and, upon rejection, the offer vanishes and there can be no contract. However, in these examples, it is assumed that the odontologist is not interested in rejecting a coroner’s offer but, rather, wishes to work with the coroner. In the example where Dr. White told the coroner, “Fine, I’ll be right over,” there was not an explicit acceptance, but acceptance could be inferred from his reply and his subsequent overt act of going to the morgue and examining the decedent. But assume that the coroner made this explicit, written offer to the dentist: “I am offering you the job of examining decedent number 1234 today and, if you find there is a bitemark on the deceased’s body, performing a bitemark analysis, all work at the rate of $100 per hour.” The odontologist’s attorney probably would be very pleased to learn that Dr. White had replied, also in writing, “I accept your job offer to examine decedent number 1234, and if I find there is a bitemark on the deceased’s body, I will perform a bitemark analysis, all at the rate of $100 per hour.” This is a so-called mirror acceptance, where the acceptance repeats and does not alter the terms of the offer. At this point, the parties would have reached a “meeting of the minds” because they have mutually and overtly agreed on the exact terms of the exchange, and this meeting of minds is required for a valid acceptance. The parties must agree on the things of value they will exchange in their bargain. Further, the parties must manifest intent at the present time to form a present contract; even though the obligations under the contract may mature in the future, the parties must intend to make their contract “here and now.” In other words, a binding contract is not formed if the parties merely make an agreement to make an agreement sometime in the future. Instead of a simple acceptance, suppose Dr. White decides to negotiate with the coroner and replies, “I accept your job offer to examine decedent number 1234, and, if I find there is a bitemark on the deceased’s body, I will perform a bitemark analysis, but all at the rate of

Contracting with the Expert Witness

$300 per hour.” In this case, there obviously has not been a meeting of the minds because the parties have not yet mutually agreed on the hourly rate of pay for Dr. White. To be valid, an acceptance must be unqualified and must not vary the terms of the offer. There is a patent ambiguity in this acceptance because the forensic dentist cannot both accept the offer of employment at $100 per hour and at the same time bargain for a higher rate of $300 per hour. Even though Dr. White began his reply with, “I accept your offer,” he actually has made a counteroffer that the coroner might, in turn, accept or reject. Several counteroffers may be proposed back and forth by both parties in the bargaining process until either both parties are happy with the terms or they come to realize that they cannot reach a mutually satisfactory agreement. The “catch” the negotiating dentist must keep in mind is that, under common-law principles, if he makes a counteroffer and starts bargaining, the original offer from the coroner becomes void. If the coroner decides to reject Dr. White’s counteroffer of $300 per hour, this negotiating dentist cannot merely come back to the coroner later and say, “Well, OK, maybe you can’t pay me $300 per hour, but I’ll take your original offer of $100 per hour,” and expect to have a valid contract. The coroner’s offer vanished when Dr. White made the counteroffer. The coroner reasonably may have engaged another odontologist in the meantime. Further complicating the situation of offer and acceptance is the well-established common-law rule that the offeror (the coroner in this example) can revoke the open offer at any time prior to acceptance by the offeree. If Dr. White (the offeree) says nothing more in reply than, “Fine, I’ll be right over,” should the coroner interpret that as an acceptance? Perhaps, but it is not clear; the odontologist might not really intend this as an acceptance. He might be thinking, though he does not say it, “Fine, I’ll be right over and I’m going to negotiate with you.” How is the coroner supposed to know that is what the odontologist really means? While Dr. White is getting ready to go to the coroner’s office, the coroner might become aware that her favorite odontologist, Dr. Smith, has arrived home from vacation and decide to call him instead to perform the exam. The coroner is well within her rights to call Dr. White again and tell him, “Never mind. We don’t need you to come over, after all.” There is no contract that Dr. White can seek to enforce. Dr. White, to his chagrin, never explicitly accepted the offer. In addition, the coroner might make a firm offer, such as “Dr. White, I am offering you the job of examining decedent number 1234 tomorrow and, if you find there is a bitemark on the deceased’s body, performing a bitemark analysis, all work at the rate of $100 per hour,

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and I need your answer by 9:00 a.m. tomorrow morning.” If Dr. White belatedly calls the coroner at 10:00 a.m. to accept the offer, the coroner would be completely free to decline if she wishes, on the basis that the offer was automatically revoked and had expired as the 9:00 a.m. deadline passed. If the offer is silent on a deadline for acceptance, the offer is open for a “reasonable” amount of time. But assume Dr. White goes to the morgue straightaway and performs the examination. Suppose the coroner phones Dr. White just after he is finished with the examination and is leaving the morgue, on his way out the door, to tell him, “Never mind. We don’t need you to come over, after all.” He has already performed the requested service; would it be reasonable for the coroner to be able to revoke her offer at this point? The coroner might claim, “We have no contract because Dr. White never accepted the offer, so I revoke the offer. I don’t have to pay him.” This situation brings up the concept of promissory estoppel. Perhaps the odontologist did not explicitly say, “I accept your offer,” in this instance, but Dr. White surely acted as if he had accepted the offer. After all, he did not try to bargain and he did not make a counteroffer; Dr. White just went to the morgue and went to work as requested. (This hypothetical does not consider for the moment the important ancillary issue of whether or not the odontologist would have had actual permission from the coroner to examine the decedent.) If this odontologist must sue the coroner for payment, the court might prevent, or estop, the coroner from claiming as a defense that there simply was no contract with Dr. White. The theory of promissory estoppel here is based on the fact that the requested service had already been completed by Dr. White before the offer was revoked by the coroner. This situation is also called promissory estoppel/detrimental reliance, which reminds us that the promisor—the coroner—is estopped from denying the contract because the promisee—the odontologist—relied on the offer and promise to his detriment. Black’s defines promissory estoppel as “[t]he principle that a promise made without consideration may nonetheless be enforced to prevent an injustice if the promisor [here, the coroner] should have reasonably expected the promisee [the odontologist] to rely on the promise and if the promisee did actually rely on the promise to his or her detriment” [1]. When the coroner said, “I’d like for you to come by the morgue and examine a decedent,” she should have reasonably expected that the forensic dentist would really do so. The court would likely rule that there is an enforceable contract in this situation. The coroner made a request and knew, or should have known, that the request would induce the odontologist to perform

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the service, and Dr. White did indeed perform the service just as if he had accepted the offer. In fact, it is not always necessary for the promisee to complete the services fully for promissory estoppel to apply; once the promisee begins the requested service, the promisor will likely be estopped from revoking the offer under common-law principles. In the situation where promissory estoppel applies, traditional consideration is not required in order to form an enforceable contract. So, once an offer and acceptance have been exchanged and bargained-for terms have been mutually accepted by the parties, the parties have an agreement. But there is yet one more essential element required in order for the agreement finally to become an enforceable contract.

30.5 Consideration The Restatement of the Law of Contracts says that consideration “for a promise is (a) an act other than a promise, or (b) a forebearance, or (c) the creation, modification, or destruction of a legal relation, or (d) a return promise, bargained for and given in exchange for the promise” [5]. The concept of consideration includes the idea that consideration is the inducement to the contract and must confer either some benefit to the promisor or some detriment to the promisee. In the preceding examples, the coroner offering the job is the promisor—the party making the promise; the promise is that, in return for the odontologist’s professional expert services rendered in the present, the expert dentist will be paid at some point in the future. The odontologist is the promisee— the party to whom the promise is made. In this hypothetical example, we can see that the promisor—the coroner—makes a promise to pay the dentist and, in exchange, the coroner receives the benefit of obtaining an agreement to have some expert odontological services done. The agreement here also results in a detriment to the promisee—the odontologist—in that the forensic dentist obligates himself by promising to spend his time and effort in traveling to the morgue and performing the examination. He may even have to cancel patients’ appointments and buy additional equipment, such as a new camera, in order to complete the analysis. Even though he promises to perform the services “now,” he knows that he will not receive payment until sometime in the future, and he further assumes some slight risk that payment may even not be made at all. Under modern contract theory, the consideration that “supports the contract” here is not the work performed by the odontologist; after all, the work will not actually be performed until sometime after the agreement has been reached. Instead, consideration is the

return promise made by the forensic dentist at the time of the agreement that he will come to the morgue and perform expert services for the coroner. Consideration is the sine qua non for an agreement to become a contract; without it, an agreement is generally not enforceable. Under old contract theory, consideration could be thought of as the thing or act that “seals the deal” and explicitly indicates to everyone interested that both parties agree to the terms and both agree to be legally bound by the contract. In a contract dispute, it does not matter whether or not the value of the consideration itself is comparable to the value of the items being exchanged under the terms of the contract; consideration can be something of nominal value. The contracting parties are free to bargain and contract as they wish, and the issue is whether or not there is consideration that has some value. This is the reason that one may be handed a contract to sign and find a dollar bill attached to be given to the signer. This contract will likely include some wording such as, “For and in consideration of one dollar and other valuable consideration, receipt of which is acknowledged….” The dollar bill is an item of real value intended to eliminate any question under old contract theory about whether or not there is consideration supporting the contract. Even though the contract might involve an exchange of items worth thousands and thousands of dollars, the dollar bill is adequate consideration— quid pro quo—to support the contract. Under modern contract theory, consideration can also be found where there is a bargained for detriment to each party to the agreement. In order to be consideration, the detriment must create an obligation that the promisor would not have incurred but for the existence of the agreement.

30.6 Defenses to Breach of a Valid Contract Offer, acceptance, and consideration must be present in an agreement in order to form a valid contract. Without each of these, there simply is no contract. In a contract dispute, one party might raise, as a defense to breach, the issue that one or another of the required elements is missing, and thus there is no valid contract to enforce. But there may be times when parties do form a valid contract, only to find that one of the parties is unable to fulfill the terms of the contract for some reason. In such a case, there are some legally acceptable defenses that may excuse a party from performance of even a valid contract. If a party does not follow through with the agreedupon terms of the contract, then he may be found to be in breach of contract, also called default. The reason for the breach may be a compelling one or not, and it is up to a

Contracting with the Expert Witness

judge or jury, not to the aggrieved party, to conclude that a particular reason is not an acceptable defense for default. A party alleged to be in default of a contract has a number of defenses that can be raised if a suit is brought. Defenses to breach of contract generally fall into three categories: (1) procedural defenses, which could equally apply to many other types of lawsuits as well, (2) real defenses, and (3) personal defenses. Procedural defenses are issues raised that will preclude the lawsuit. Real defenses are issues raised that generally might result in a determination that there was no valid contract in the particular case. If a valid real defense is successfully asserted by the defendant, the straightforward result will be a ruling that there was a void contract. On the other hand, personal defenses are “excuse defenses”; that is, the defaulting party admits there was a valid contract between the parties, but insists there is also a valid excuse for not complying with the terms of the contract. Asserting a personal defense successfully may result in voidable contract; that is, it is up to the judge’s discretion whether or not to void the contract under the particular circumstances of the case. Several different forms of each of these defenses will be considered. To begin a consideration of defenses to breach of contract, let us suppose that the odontologist, Dr. Olive, and the coroner execute a perfectly valid contract for Dr. Olive to attempt a dental identification of an unidentified decedent. Say that Dr. Olive is in his car on his way to the morgue and is hit and seriously injured by a drunk driver who was speeding through an intersection and ran a red traffic signal. Virtually everyone would agree that this is a circumstance beyond this forensic dentist’s control, and it would be perfectly understandable that Dr. Olive will not somehow be able make his way to the morgue and examine the decedent in spite of his serious injuries. Dr. Olive might raise the personal defense of impossibility should the coroner decide to sue him for breach of contract for failing to perform the examination. A defense related to impossibility is force majeure (a “greater force”). This defense is invoked typically when some catastrophe such as a flood or a war prevents a contract from being carried out by one of the parties. Suppose that odontologist Dr. Green and a coroner have a standing contract for Dr. Green to provide forensic dental services to the coroner’s office. One day, as Dr. Green is preparing to go to the morgue to perform a bitemark examination, a tornado strikes and destroys the morgue. If the odontologist is unable to perform the examination at the time designated by the coroner because of such physical damage to the morgue, the coroner probably will not be successful if a suit for breach of contract is filed for failing to perform the exam. Dr. Green might claim as a defense a force majeure preventing the

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performance of the agreed-on services. This defense is sometimes also called “an act of God.” But a totally different situation arises if hypothetical forensic dentist Dr. Green looks out the window and thinks, “I know that I signed a contract to examine the decedent today, but the weather is beautiful, so I’m going to go play golf instead.” All would likely agree this reason is simply not acceptable to excuse the golfing dentist from complying with the terms of the contract and performing the work promised to the coroner. While going golfing is probably not a valid excuse for defaulting on a contract, there are still a few more defenses that may excuse a party’s breach of contract. If a lawsuit becomes necessary for breach of contract, a threshold requirement is that the complaining party must bring suit within the time period allowed under the statute of limitations for that particular jurisdiction. In many jurisdictions, the controlling statute of limitations typically requires a suit for breach of contract to be brought within 4 years of signing the contract, but this may vary from place to place. If a lawsuit for breach is not timely filed, the defendant could claim the procedural defense that the statute of limitations has run and has barred the suit. Another threshold issue considered by the attorneys involved is whether or not the lawsuit has been filed in the proper court; that is, does the particular court have proper jurisdiction over the case? In the absence of an express provision in the contract specifying where a suit may be filed, a lawsuit for breach of contract must normally be filed in the jurisdiction where the contract was formed. For example, imagine that a medical examiner in California makes a contract with an odontologist who practices in Oregon. If the odontologist finds it necessary to sue the medical examiner for payment, the lawsuit could not properly be filed in Louisiana. It might be an arguable point whether the contract had been formed in California or in Oregon, but it certainly was not in Louisiana, and a court there would have no jurisdiction over and no interest in this case. The court must also have subject matter jurisdiction over the case. If the odontologist files the suit for breach of contract against the medical examiner in, say, a probate court, that court would not have the proper subject matter jurisdiction to hear the case. If a lawsuit is filed in an improper court, the defendant can raise the procedural defense of a plea to the jurisdiction and request that the court dismiss the case for want of jurisdiction. (As a practical matter, this would not finally dispose of the suit because the plaintiff would likely just refile the lawsuit in the proper court.) A further threshold consideration is whether or not the party filing the lawsuit has standing to bring the suit.

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The plaintiff must have a material interest in the suit and, generally, a third party may not bring a lawsuit for breach of contract on behalf of the true complainant. In addition, the proper defendant must be named in the suit. A simple misnomer, such as naming the defendant as “Dr. Bob Green” rather than “Dr. Robert Green,” will not excuse a proper defendant from the suit. A true misidentification, though, such as mistakenly naming the defendant as “Dr. Robert Green” when the actual defendant is Dr. Steve Jones, would be a valid defense for Dr. Green and excuse him from the suit. Unfortunately for Dr. Green, however, the burden of proof shifts to Dr. Green and, to avoid further complications, he should just ignore the improper suit, but must go to the trouble of proving to the court’s satisfaction that he is not the correct defendant. Incorrectly naming a defendant in his personal capacity, such as “Dr. Robert Green,” rather than under a corporate identity—for example, “Robert Green, DDS, PC”—may or may not excuse the defendant from a lawsuit depending on the jurisdiction and the specific facts of the particular case. Another personal defense can be that of mutual mistake. Consider again the example of the Texas rancher, the city fella, and the ambiguous red and white horses. The city fella really thought that he was buying a dozen horses. The Texan really thought that he was selling just two horses. How can a judge fairly resolve this mutual misunderstanding? It is not possible for the judge, here, to award the standard contract remedy of expectation damages—that is, to put the parties in the positions they each expected to be in after their deal had been completed. Whichever way the judge would rule, one of the parties would be very unhappy. Either the city fella would have to pay $10,000 for just two horses instead of the dozen that he thought he was buying, or the rancher would have to part with all of his horses instead of just the two that he thought he was selling. Therefore, rather than awarding expectation damages, the judge could declare that the parties have made a mutual mistake—both parties are wrong—and then “turn the clock back” and put the parties back in the positions they were in before the deal was executed. The judge can order rescission of the contract; that is, he voids the deal, and the city fella gets his money back and the rancher gets his red and white horses back. Courts typically do not like to order the relief of complete rescission of contract, though, and will usually go to some lengths in an attempt to find that a contract existed between the disputing parties. Suppose that Dr. Olive, from a previous hypothetical example, decides to sell his forensic dentistry practice after his car wreck and then retire. Suppose that

Dr. Green wants to buy the practice and writes a contract that includes a “do not compete clause” such that “Dr. Olive agrees never to practice dentistry anywhere in this state again.” Then, say, 5 years later, Dr. Olive decides to “unretire” and he moves 300 miles across the state from Dr. Green and opens a “dental spa” offering manicures and foot massages while patients are tanning and having their teeth whitened. Dr. Green might claim that Dr. Olive had breached their contract, but Dr. Olive might argue that such a restrictive covenant not to compete is not reasonable and could discourage commerce. Dr. Olive might claim as his real defense to breach this provision is against public policy. A restrictive-covenant-not-to-compete issue or a provision that is against public policy might not often arise in a routine contract between a coroner and an odontologist. Another real defense to an otherwise valid contract, though another issue not likely to arise in an agreement between an odontologist and a coroner, is lack of capacity. Lack of capacity generally arises when either (1) a party is under the disability of minority (that is, the party is a minor—generally, for contract purposes, under the age of 18 years), or (2) a party does not have the requisite mental capacity needed in order to form a binding agreement. A real defense to a disputed contract might be that the defaulting party had been forced to sign the contract under duress and thus the contract was not mutually and freely agreed to by both parties. Duress may be “threats of bodily or other harm, or other means amounting to or tending to coerce the will of another, and actually inducing him to do an act contrary to his free will” [1]. It would be difficult to envision circumstances where either the coroner or the odontologist would have been forced via threat of bodily harm by the other party to sign a contract for professional services against his or her will. Now suppose that Dr. Black is an aspiring odontologist and needs to perform a certain number of rare bitemark examinations and analyses in order to meet the requirements to become board certified by some national organization. Suppose the coroner is aware of this; instead of calling Dr. Smith, her favorite, established odontologist, but whom the coroner would have to pay $5,000 to perform the bitemark analysis, she calls Dr. Black, who “needs” the case, and offers to “let” him perform the bitemark examination—if he is willing to accept a payment of $100. Say that Dr. Black happily agrees and performs an exemplary bitemark analysis, but then later learns that the other, experienced odontologist would normally be paid $5,000 for the same

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work. If he decides to withhold his report until the coroner pays him a higher fee, does he have a defense if the coroner sues him for breach? Is there anything Dr. Black can do about the payment he previously agreed to, but now feels was unfair? If one party unfairly takes advantage of the other during the bargaining phase of contract formation, the court might find the offending party guilty of unfairness, overreaching, or making an unconscionable contract. These findings are generally made to protect a weak party where the terms of the contract are “so one-sided as to oppress or unfairly surprise [the] party” [1]. But for Dr. Black, the aspiring odontologist, a welleducated adult professional and arguably of adequate mental capacity, the court might have difficulty finding that the coroner had taken advantage of this situation; tough negotiating is not the same thing as unfairly taking advantage of a weak party. After all, in spite of the paltry payment, Dr. Black did otherwise want to do the bitemark case in order to meet his certification requirements. The court might find that there is no remedy here for Dr. Black because of the long-standing, pragmatic concept informally known as the “toughous luckus” principle that the coroner might invoke (another concept from Judge Spurlock’s contracts class). Dr. Black is a competent professional and has freely agreed to the offer from the coroner and has freely agreed to be bound legally by the agreement. Since courts will allow the parties great freedom to contract—including the freedom to sign an unfavorable contract, if one wants—Dr. Black would be stuck with the contract terms with which he had agreed. Tough luck, Dr. Black. If a party receives notice from a court that he is being sued for breach of contract, the notice should never be ignored, even if it appears that one has been incorrectly named as a defendant or that the local statute of limitations would bar the suit; the complaint should be timely answered in some way (consult an attorney). If the notice is simply ignored and the defendant declines to be present in court as summoned, the complaining party could be awarded a default judgment against the defendant. The complaining party generally does not win automatically if the defendant is absent; the case must be proven even if the defendant elects not to participate in the process. It is obviously difficult, though, for the defendant to raise defenses to breach of contract if he or she is not present at the appointed time in the proper court to present these defenses. There are some defenses to a default judgment, and there are appeals that might be made after an unfavorable verdict on a breach of contract case, but those are beyond the scope of this chapter.

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30.7 Remedies for Breach Suppose a lawsuit for breach of contract is timely and properly filed by a complaining party, the defendant has no good excuse or defense for defaulting, and this defendant is found by a judge or jury to have breached the contract. How would the court enforce the contract? What are the remedies for breach that the plaintiff might be able to pursue? Remedies for breach of contract can be classified broadly into two categories: legal remedies and equitable remedies. Legal remedies are generally those in which an award of money damages can adequately compensate the complaining party. (At one time, the distinction between legal and equitable remedies was important in determining which court had jurisdiction over the matter. This could be vitally important to the outcome of a case; for example, courts of law were bound by the statute of frauds while courts of equity were not. The distinction generally is no longer relevant.) For example, suppose a province has a statute that clearly says a contract made with a person under the age of 18 years is not valid. Suppose Dr. Blue practices dentistry in that province and he sells a 16-year-old patient a motorcycle, the patient agreeing to make monthly payments to the dentist. The 16-year-old patient wrecks the motorcycle the first day he has it and, of course, never makes any payments to Dr. Blue; the dentist then sues the 16-year-old for breach of contract. An award of money damages to Dr. Blue would “fix” the situation so there is a legal remedy available, and there is an applicable statute as well. What might be the result? The court might rule that the contract is void and order rescission because the statute in the hypothetical province clearly says one cannot make a valid contract with a person under the age of 18 years. The defaulting under-age patient would likely claim the defense of “disability of minority.” Dr. Blue would be out of luck, toughous luckus redux. However, please note an exception to this rule that if Dr. Blue contracts with a minor patient to provide his needed dental treatment, that contract could be enforceable. A contract for necessaries, which includes dental treatment in most common-law jurisdictions, can be enforceable even though the contracting patient is not of legal age. Equitable remedies, on the other hand, are those that may be available when there is no adequate legal remedy for the plaintiff. Equitable remedies are based on the concept of doing what is “just and right” for the disputing parties. An equitable remedy might compel the breaching party to perform some particular act; that is, the

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court might order specific performance by the defaulter. Reconsider the example of Dr. Green, who decided to go golfing instead of to the morgue per his agreement. If the coroner sues Dr. Green for breach of contract, the court might order specific performance and direct the golfing odontologist to go to the morgue at some particular date and time to perform the examination. But would this order be the best solution? It would put the coroner in the position she expected—namely, having the contract honored; the needed bitemark examination would be done. But the coroner might be very upset with Dr. Green by the time he arrives, and the forensic dentist, in turn, quite ill at ease in the morgue. In short, ordering Dr. Green to go to the morgue might result in a very uncomfortable situation for everyone involved. Things could get really out of hand and the irate coroner might even physically assault the golfing odontologist, obviously not a result the judge intended at all. Further, while the situation is being sorted out in court, the decedent remains at the morgue for an excessive length of time, causing great and unwarranted distress to the family, as well as probable deterioration of the bitemark evidence. Dr. Green will probably not be able to perform the best work under these conditions, might be in a rush just to get away from the morgue, and carry out only a hurried, superficial examination of the decedent. Could the court not order Dr. Green to go to the morgue anyway and perform the bitemark exam “to the highest standards of the profession”? Well, of course, the court could order that, but who would say whether or not the exam was really done in compliance with the order? Who would monitor the examination and who would say whether it is performed up to highest standards or not? The judge really does not want to have to monitor the odontologist’s work, and this type of situation is one of the reasons for the general principle that most courts simply will not order specific performance as the remedy for default on a personal services contract. Specific performance is often available, however, as a remedy for breach in cases involving a contract for the sale of land or works of art. These sorts of items are considered to be unique, so an award of mere money damages will not adequately compensate the complaining party for default on a contract for the sale of such items. The converse of specific performance is when the court orders a party not to perform or to cease performing some particular act; that is, the court issues an injunction. Suppose in the following hypothetical example not involving a contract, a general dentist learns that the odontologist in his town, Dr. Gray, is publicly

advertising as a “specialist in forensic odontology.” Suppose in this general dentist’s particular state the regulations of the dental board say a dentist may advertise that he is a specialist in only those fields designated as specialties by the national dental association, and forensic odontology does not happen to be among those approved specialties. If the general dentist complains to the dental board about Dr. Gray’s advertisements, what could the dental board do? The dental board might levy a monetary fine on the advertising odontologist, but suppose Dr. Gray keeps on advertising in spite of the fine. The offense may not be serious enough for the board to suspend or revoke Dr. Gray’s dental license, so what could the board do next? The dental board might sue the advertising odontologist, but an award of money damages to the board or to the complaining general dentist will not fix the situation. What they really want is for Dr. Gray to stop his improper advertising. Here, the dental board might ask the court to issue an injunction, an equitable remedy. The court might order Dr. Gray to cease his advertisements until a hearing can be held where he will have a chance to present his side of the case. While ignoring the advertising regulations of the dental board might not be a critical violation in itself, if the contumacious advertising odontologist Dr. Gray willfully ignores the court’s injunction and continues advertising, he could find himself in very serious trouble, perhaps subject to contempt-of-court proceedings. As a side note, Dr. Gray might, though, raise a freedom-of-speech defense for his advertisements [6]. For a complaining party to be awarded an equitable remedy, this party must have “clean hands” when going before the court. That is, the plaintiff must not be guilty of some wrongdoing himself (“in pari delecto”) in the dispute. If the advertising odontologist, Dr. Gray, could show in his defense that the complaining general dentist also was guilty of illegal advertising, the court probably would not award the complaining general dentist equitable relief. As another aside, offers made by advertising generally do not create contracts. If a general dentist places an advertisement in the local newspaper reading “best porcelain crowns in the world for $100,” that offer would be unenforceable as a contract because it is not specific; the offer is not made to any particular person. Of course, this advertising general dentist would certainly open himself to likely charges of deceptive advertising and unethical conduct. One can see that some of these contract remedies are forward looking—that is, the remedy addresses potential future problems—and some remedies are backwards looking—the remedy addresses past events. The type of

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remedy sought depends on the terms of the contract and the nature of the alleged breach in the particular case. But, again, the forward-looking remedies of specific performance and injunctive relief are not the usual sorts of remedies courts order for breach of contract. The general idea of awarding a remedy for breach of contract is for the judge to try to put the prevailing party in as good a position as she had expected to be in, if the contract had been performed as agreed. This typical remedy in common-law jurisdictions is called expectation damages and is most often a compensatory award of money. Contract remedies in jurisdictions that follow English common-law traditions are intended only to compensate the injured party for her loss and are rarely punitive in nature. A simple, straightforward example of this sort of compensatory expectation remedy would arise where the coroner does not pay a forensic dentist at the $100 per hour rate agreed on, but tries to pay $75 per hour instead. The court could order the coroner to pay the forensic dentist the additional $25 per hour that is due under terms of contract. The concept of expectation damages reinforces the idea that terms of a contract must be definite and it is best if in written form. It is very difficult for a judge to remedy a broken contract situation for a party by giving what was expected, if the judge cannot determine just what the party expected. Better than leaving it up to the court to predict what a party might have expected under a contract, the parties can plan for and include express agreements for the consequences of a breach. For example, the coroner might decide to give the golfing Dr. Green a second chance with another bitemark case, but have the foresight to include a written provision in the contract specifically to protect the office in case Dr. Green defaults again. This clause might say something such as, “In the event Dr. Green does not perform the services agreed to, he will pay the coroner’s office $10,000,” as incentive to make sure the wayward Dr. Green shows up this time and does the work agreed to. But as mentioned before, remedies for breach of contract are intended to compensate the aggrieved party and not to punish the defaulting party—a $10,000 payment in this case would probably be considered by the court to be punitive and therefore unenforceable. The coroner might instead include a clause in the contract, though, that says something to the effect of “in the event Dr. Green does not perform the services agreed to, he will pay the cost of reasonable expenses required to hire another odontologist.” This provision could be enforceable. The coroner might name a specific, reasonable amount such as, “in the event Dr. Green does not perform the services agreed to, he will pay $500 to the coroner’s office to cover the reasonable expenses

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required to hire another odontologist.” This provision also could be enforceable. It would greatly enhance this claim if the coroner could show that it would actually cost an additional $500 over and above Dr. Smith’s normal fee to cover travel expenses to persuade him to come to the morgue on short notice in place of Dr. Green. A contract provision of this type is intended to cover liquidated damages; namely, it is a specific amount agreed on in advance to cover additional, reasonable expenses caused to the plaintiff in case of the defendant’s default. As with other remedies mentioned, liquidated damages cannot be punitive in nature but rather are compensatory. For the case where the erstwhile golfing odontologist Dr. Green defaults on his contract with the coroner, what remedy could the coroner have if specific performance is likely not available, and the coroner has not provided for liquidated damages in the contract? When an employee defaults on a personal services contract, the employer is usually allowed to recover the reasonable costs of recruiting another employee, even if the contract is silent on that issue. However, recovery of actual, reasonable costs is probably the only remedy available for an employer in this situation. Consider now the example of Dr. Gold, who is a very unethical odontologist. Imagine that the trusting coroner calls him and says, “I’d like for you to come by the morgue and examine a decedent. I think there might be a bitemark on the deceased’s body. I’ll leave a $1,000 retainer check for you at the front desk.” If Dr. Gold decides to stop by the morgue to pick up the check and then continues on to the lake to go fishing—never intending to do the bitemark examination at all—what could the coroner do? Calling the police and trying to have Dr. Gold arrested for stealing the check (larceny) would not really do. After all, the check would be payable to Dr. Gold and, presumably, a morgue employee would voluntarily hand it over to the forensic dentist, so it would be difficult, if not impossible, to prove a claim that Dr. Gold stole the check. This unethical odontologist would probably claim that the parties did not have a contract and therefore assert that there was no requirement to perform any services at all, claiming the check was just a “gift” from the coroner. In this case, the best equitable remedy for the coroner would likely be a suit based on the common-law concept of unjust enrichment. The coroner could sue Dr. Gold and ask the court to imply a quasicontract in this situation. While there actually is no express contract, under the theory of quasicontract, the court could imply the “legal fiction” that a contract does exist and enforce the appropriate contract remedy against this

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defaulting fishing odontologist. The court would most likely order Dr. Gold to return the $1,000 to the coroner’s office. The amount of $1,000 is called restitution damages—an award that would restore the plaintiff to the former position before the unethical Dr. Gold was unjustly enriched. This remedy is also known as imposing a constructive contract. Consider a hypothetical situation where the coroner calls Dr. Brown, the new odontologist in town, to examine a decedent for a potential bitemark because the coroner’s favorite odontologist, Dr. Smith, is out of town on vacation. Say that Dr. Brown arrives at the morgue and spends several hours taking numerous photographs, carefully measuring and documenting the injury, and even making an impression of the patterned injury. But suppose the coroner learns that Dr. Smith has arrived home from vacation early, and the coroner calls Dr. Brown at the morgue in the middle of the examination to tell him, “Never mind. We don’t need you after all. Please send the photographs and the impression you made over to Dr. Smith so that he can work up this case for me.” Dr. Brown might reasonably ask, “Well, OK, but are you going to pay me for the work I’ve done so far?” The coroner might say, “Why, no, of course not! You did not complete the bitemark examination as required by our contract.” What could Dr. Brown do? Even though it is not Dr. Brown’s fault that he did not complete the services, the coroner is technically correct that Dr. Brown has not finished the agreed-on job. The photographs and impression might be evidence in a criminal proceeding, so Dr. Brown might not be able to withhold them as “ransom” for his payment. If Dr. Brown sues the coroner for payment, a judge might invoke promissory estoppel against the coroner, as previously discussed, and award the odontologist the remedy of quantum meruit in this case. Perhaps the plaintiff Dr. Brown is not entitled to payment of the full amount he would have expected under the contract terms, but surely he does merit some quantum of payment for the professional services he has performed in good faith. The judge might calculate some reasonable hourly rate of pay for a typical odontologist and then order the coroner to pay Dr. Brown the amount deserved based on the time spent at the morgue. Dr. Brown might respond: Well, that hourly rate is acceptable for the time I was at the morgue, but I also had to cancel a day’s worth of patient appointments so that I could go to the morgue, I had to pay for gas to drive 50 miles to the morgue and 50 miles back home, I had to purchase a brand new camera with an expensive macro lens and also

buy several brand new cartridges of impression material to work on this case. And, because I cancelled her appointment, Paula Patient is suing me for malpractice, claiming “abandonment of a patient” because she had to find another dentist to relieve her excruciating pain. What about all those expenses?

Dr. Brown’s question raises several different issues. When expenditures in order to be able to perform the required work can be shown, the court would likely award payment for those expenses. For example, the court might award the gas money, the cost of the cartridges of impression material, and maybe even the cost, or at least a prorated portion of the cost, of the new camera and lens. These are called reliance damages— that is, actual, reasonable costs that Dr. Brown incurred because he relied on the contract and a reasonable assumption of payment as agreed. But the court would probably not look favorably on awarding damages for the events that are speculative. For example, Dr. Brown claims that he had to cancel a day’s worth of appointments and says that he can show from his daily balance sheets that he averages $3,000 per working day in gross receipts. Should he be awarded $3,000 to make up for his missed appointments? Not likely. First, Dr. Brown—not the coroner—voluntarily accepted the job offer and cancelled the appointments. Dr. Brown had full control over which appointments were to be cancelled. Second, while his balance sheets show that Dr. Brown does average $3,000 per working day gross production, on some days he produces $10,000 worth of treatment but on other days just $500; how is the judge to know what Dr. Brown actually would have produced on the day in question? Also, it is certainly possible that, even had Dr. Brown been in the office, the patients may have cancelled some appointments that day; it is speculative whether or not they all would have shown up and paid as scheduled. Courts generally do not award damages where the amount is speculative. It should be noted that there is a difference between speculative amounts and estimated amounts. Courts sometimes must estimate the proper amount of damages to be paid, but this is a different situation from that of speculating whether or not damages would have been incurred. If Dr. Brown pursues his additional claim that the coroner should be responsible for a potential award of money damages made to Paula Patient for Dr. Brown’s alleged malpractice, he would be asking for the remedy of consequential damages, which are those that do not “flow directly and immediately from the act of the party, but only from some of the consequences or results of such

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act” [1]. But Dr. Brown would be hard pressed to prove that the coroner should be somehow responsible for an unfavorable outcome of the malpractice suit here since, again, Dr. Brown himself was ultimately in control of which appointments were to be cancelled. In addition, and probably more importantly, Dr. Brown almost certainly has the legal obligation in virtually every jurisdiction to provide proper emergency coverage by another dentist in Dr. Brown’s absence for his patients of record; it is hardly the coroner’s fault that Dr. Brown did not do so. There is also a remedy known as reformation. If a judge finds a contract to be unfair or oppressive or too ambiguous, the judge might reform the contract by either changing or striking out the offending passages. Consider again the previous example of the aspiring odontologist Dr. Black being paid just $100 for what was actually $5,000 worth of professional services. If the judge determines that the contract is unfair, one way to reform the contract would be for the judge to order the coroner to pay Dr. Black a reasonable fee instead of the $100. In the previous example of Dr. Green buying Dr. Olive’s practice and inserting an unenforceable restrictive covenant not to compete in the contract, if the agreement is otherwise valid, the court might just strike out the offending clause and let the rest stand. While the judge might void the entire contract if the agreement is not salvageable by judicious editing, courts will often go to great lengths in an attempt to “find” a contract. When Dr. Green purchased Dr. Olive’s forensic dentistry practice, assume Dr. Green had included an unreasonable “do not compete clause” in the contract, and the court struck out this provision and let the rest of the contract stand. Imagine that, in addition to selling his practice to Dr. Green, Dr. Olive also owned the office building where his practice had been located and he leased his former office space to Dr. Green for $2,000 per month. When Dr. Green realized that he could not successfully operate a forensic dentistry practice, he stealthily packed up his office one weekend, moved out of Dr. Olive’s building, and joined another dental practice across town. Dr. Olive found the office vacated, but made little attempt to locate Dr. Green, and he did not make much of an effort to lease the empty office space either. The office sat vacant for 3 years. When Dr. Olive ran into Dr. Green at a dental society meeting, Dr. Olive claimed that Dr. Green owed him $72,000 rent for the 3 years during which the office sat empty. In addition, because Dr. Green did not go to the morgue to do the bitemark examination but went golfing instead, the coroner was irate with him. Another odontologist had been willing to come to the morgue on short notice to perform the exam, but at twice the

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amount that Dr. Green would have charged, as well as requiring a first-class airline ticket and staying at the local five-star hotel at the coroner’s expense. While the coroner was making these arrangements, the decedent remained in the autopsy suite, crucial bitemark evidence was lost, and the body began decomposing. The decedent’s family and the police department are now incensed at the coroner, and the family has threatened to pursue some sort of legal action. The coroner is infuriated with Dr. Green for causing this situation and fully intends to sue Dr. Green for any damages that may have to be paid the decedent’s family. While Dr. Green is clearly guilty of breach of contract in these situations, he would not be legally responsible for all of the resulting damages. Even when a defaulting party is clearly in breach of contract, the complaining party still has a duty to attempt to mitigate the resulting damages. The plaintiff cannot simply stand back and allow the situation to worsen and then expect the defaulter to pay for all the resulting damages. Like it or not, in spite of the defaulter’s actions, the plaintiff does retain some control over the situation. Dr. Olive has a duty to make a reasonable, genuine attempt to find another suitable tenant to lease the empty office space. The coroner has a duty to care for the decedent’s remains properly and preserve evidence while locating another odontologist. Dr. Green would likely have to pay reasonable damages to both plaintiffs, but probably not the full amount these plaintiffs would request because they did not attempt to mitigate the damages. Now, consider one last hypothetical situation, also an egregious situation. Suppose the coroner and Dr. Jones, her favorite, established odontologist, both practice their respective professions in province A. Imagine that brand new odontologist, Dr. LeBlanc, is properly licensed and practices dentistry in province B, but is not licensed to practice dentistry in province A. Suppose Dr. Jones is not immediately available when the coroner needs a bitemark consultation, so the coroner calls young Dr. LeBlanc to come over from his office in province B to do a bitemark exam at the morgue in province A, and they execute a perfectly valid, well-written contract. While Dr. LeBlanc is en route to the morgue, Dr. Jones finds out about this turn of events, and he maliciously calls the coroner to tell her, “You can’t let that LeBlanc do this examination. He is incompetent and untrustworthy. Not only that, he’s not even licensed to practice dentistry in our province, so he can’t legally do the examination here, anyway.” Imagine, however, that Dr. Jones knows Dr. LeBlanc is fully competent and is fully trustworthy. Suppose Dr. Jones knows full well that a valid dental license is not required in hypothetical province A in order for a

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dentist to perform a forensic examination on a deceased person under direction of the coroner. In fact, Dr. Jones has written an article about this very situation that was recently published in the journal of his province’s dental association. Assume the trusting coroner calls Dr. LeBlanc en route and tells him, “Never mind. We don’t need you, after all,” based on Dr. Jones’s deceptive representations, and then the coroner executes a contract with despicable Dr. Jones to perform the bitemark examination. Is there any recourse for Dr. LeBlanc? Aside from the case he might try to make for slander (oral defamation of character), Dr. LeBlanc might also sue Dr. Jones under the uncommon claim of tortious interference with contract (tortious, from tort, means “wrongful”) [1]. Dr. LeBlanc had a valid contract with the coroner and Dr. Jones has wrongfully interfered with that contract; in fact, he has induced the coroner to break the contract. This could be one of the rare situations where a court might consider awarding punitive damages in a contract situation. The court could calculate the total amount of fees and expenses that would probably have been payable to Dr. LeBlanc if the contract had been honored and then order Dr. Jones to pay Dr. LeBlanc triple that amount. (Note the interesting situation here: Dr. LeBlanc had a broken contract with the coroner, not with Dr. Jones, yet it is Dr. Jones, a third party, who has to pay the damages. Dr. LeBlanc may have a further claim for breach against the coroner, as well.) Punitive damages are awarded to punish the offending party, not necessarily to compensate the victim, and to deter others from similar bad conduct. In order for the court to award punitive damages, the defendant—Dr. Jones—must have acted with “oppression, fraud, or malice, express or implied” [1]. Dr. Jones might be found to have acted with both malice and fraud because it would be quite possible for Dr. LeBlanc to show that Dr. Jones knew that what he was telling the coroner was untrue on account of Dr. Jones’s published article about this very issue. Not to put too fine a point on this, but when one carefully analyzes this situation, it will be seen that this remedy does not directly address the breach of contract. It is not of concern under this remedy that Dr. LeBlanc is awarded much more than the usual remedy of expectation damages would warrant. The underlying remedy here is actually intended to punish Dr. Jones for his wrongful actions, not merely to compensate Dr. LeBlanc for the default by the coroner. In the hypothetical examples involving the remedy of expectation damages, the court orders the defaulting party to pay money damages to the complaining party. While the court may order that payment be made—that is, the complaining party may receive a judgment against

the defaulting party—this judgment does not necessarily mean that the defaulting party will comply with the order instantly. If the defaulting party does not comply by making the court-ordered payment in a timely manner, the plaintiff can next ask the court to issue a writ of execution. This writ will generally direct the sheriff or other appropriate official in the jurisdiction to go to the defaulter’s residence or place of business and either demand and obtain payment from the defaulter or seize property of suitable value from the defaulter.

30.8 Typical Parts of a Contract The following section contains a consultant agreement typical of the kind that could be written for a forensic odontologist making an agreement to provide expert services to an attorney. As previously mentioned, there are few constraints on the precise form and content of a contract, so a contract may vary widely in scope and content from this sample. Whether the odontologist relies on his attorney to write a contract or to review a contract written by another, it is essential for the odontologist to read and understand the provisions of the contract he is signing. Once a competent adult such as an odontologist signs a contract, it is not very probable the defense of “Well, I didn’t actually read the contract; I just signed it” can be used successfully in case of default. The signer is supposed to read the contract before signing it. The contract in the next section is entitled “consultant agreement.” The party writing the contract should title the document in a way that briefly, but adequately, describes the document. There are no specific requirements for which of the following sections must be included or what they must be titled—other than, again, the titles should adequately but briefly describe the content of the sections. The titles might be numbered and highlighted in some way, such as in italics or bold print, to serve as “landmarks” for finding one’s way around in the contract. Some writers include line numbers for the text of the contracts they write. The first few paragraphs of the contract are usually called the recitations. The recitations are short introductory paragraphs that name the parties, give other information about the parties, and state a general overview of the purpose of the contract. Note in this example that the consultant is designated to be an “independent professional.” Though this phrase is not binding in a court, it does indicate the intention of the parties. The distinction between being an independent contractor and an employee could become very important to the odontologist for the following reason: Generally, only a state

Contracting with the Expert Witness

actor, not a private citizen, can commit a federal civil rights violation, and “state actor” could be interpreted as “government employee.” Thus, a true independent contractor, as a private citizen, likely would not be legally liable should a civil-rights violation occur to the suspect during the course of the investigation. While the contracting parties may designate the odontologist’s status as an employee or an independent contractor as they wish, the court looks at the actions of the parties, not the designation they elect, when determining this status. If the odontologist, even while calling himself an independent contractor, acts as if he were a government employee, the court will probably consider him to be a government employee. Importantly, if the odontologist works in concert with a state actor, such as a law-enforcement agency, then the odontologist also will likely be considered to be a state actor. In a recent legal case [7], the defendant in a criminal trial involving a bitemark became the plaintiff in a socalled “1983 lawsuit” (from 42 U.S. Code §1983, where the federal statute applicable to civil rights violations is found). This plaintiff alleged U.S. federal civil rights violations and named an out-of-state “independent contractor” odontologist as one of the codefendants. The court determined that this odontologist was actually a state actor for the purposes of the lawsuit, rather than an independent contractor as the odontologist claimed, and thus ruled the odontologist could properly be included as a codefendant in a civil-rights suit. However, as a state actor, this odontologist was also entitled to, and shielded by (in this particular case) qualified immunity (also known as official immunity)—immunity from judgment that a true independent contractor probably would not have enjoyed. Qualified immunity will not protect one from a “1983 lawsuit” in every case, but under the specific facts of this case, the odontologist’s motion for summary judgment was granted, and he was dismissed as a codefendant from the civil-rights suit. Note that, in these recitations, it is explicitly stated that payment to the expert is not dependent on the outcome of the case because, as has been mentioned, contingency fee arrangements for an expert’s testimony are not permitted because they are contrary to public policy. Further, payment here is due regardless of any arrangement the client-attorney has with his own client. Ultimately, it is the attorney’s client who is actually paying the expert’s fee, of course, but the expert probably stands a better chance of collecting the fee directly from the attorney than from the attorney’s client. Of course, it is quite possible that the actual party, such as the defendant, may take it upon himself to locate and contract with an expert of his own choosing.

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This raises the interesting ancillary question of just exactly who hires the expert witness—the attorney or the attorney’s client. The expert is usually retained by the attorney, but in fact provides his expert services for the attorney’s client. An exception to this generality may be found in civil cases, though, in a malpractice case, for example, an attorney may hire an expert to provide services directly to the attorney. This situation most often arises when the attorney retains an odontologist to help the attorney determine whether or not a client has a civil malpractice case financially worth pursuing. The expert in this situation is known as a consulting expert (also called a nontestifying expert) and his findings and opinion may be kept secret by the attorney; that is, this expert’s opinion may not be “discoverable” as long as the attorney does not intend to call this expert to testify at trial. In contrast to the consulting expert is the testifying expert, an expert witness the attorney does intend to call to testify at trial. The testifying expert’s opinion is discoverable and will almost certainly be disclosed to opposing counsel during pretrial procedures in civil cases. Keep in mind that if the testifying expert becomes aware of the consulting expert’s opinion, then the consulting expert’s opinion may become discoverable as well. While a consulting expert’s opinion that is adverse to his own client’s civil case might not have to be disclosed to the opposing party, the odontologist should be aware of a significant difference that arises in criminal cases. In the circumstance where the odontologist (or any other forensic analyst) is retained by the prosecutor in a criminal trial in U.S. courts, if the odontologist or analyst finds exculpatory evidence—that is, evidence that tends to exclude the suspect as having committed the crime with which he is charged—that exculpatory evidence must be disclosed to the defense under Brady v. Maryland [8]. It is clearly the prosecutor’s duty to deal with this issue, but the odontologist might want to keep a wary eye on the process in order to avoid being named as a codefendant in a U.S. federal or state civilrights action brought by the suspect if the exculpatory evidence should not be timely disclosed. The author feels that it is very unlikely that a suspect could successfully prosecute an allegation of a federal or state civil-rights violation against an odontologist based on nondisclosure of exculpatory evidence. Even so, as this book goes to press, the author remains involved in a long-running case where this very action was threatened [9]. It is probably not the odontologist’s legal duty under Brady to disclose the exculpatory evidence to the defense, and once the odontologist advises the prosecutor of the exculpatory evidence, he or she likely has no further legal obligation. Nevertheless, as an ostensibly

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neutral expert scientist and advocate for the truth, does not the odontologist have a moral or ethical duty to make sure exculpatory dental evidence is disclosed? It is simply better to avoid being entangled in similar thorny situations, if possible. Another provision the odontologist might want to include in the recitations is an explicit statement that the medical examiner or coroner gives the odontologist permission to examine the decedent in the morgue. The odontologist might wish to indicate here that a second opinion will be requested—for example, in a bitemark case—from another odontologist. Conversely, the prosecutor or plaintiff’s attorney may require in the contract that the odontologist not send evidence to anyone else without explicit permission. The engagement fee is taken up next. This fee is also called a retainer, and is more or less a good-faith deposit made by the client. The expert may draw reasonable fees and expenses from this fund until it is exhausted. Fees are next addressed. Various fees are listed for the various types of services that the odontologist may be called on to perform. Note that fees are listed here for auxiliary personnel as well and that the odontologist might want to include provision for fees for an assistant in case the coroner’s office does not provide one. Graphic design and exhibit preparation are also listed because the fees can be substantial for preparing such items as several duplicate sets of presentation-grade dental stone models and professionally prepared charts and posters for use in court. Provision for expenses of the odontologist is considered. Expenses are out-of-pocket outlays made by the odontologist, such as for airline tickets or lodging and meals. If a suspect is in a jurisdiction where the contracting odontologist is not licensed to practice dentistry or if the suspect is far away, the odontologist may have an expense if he must arrange for and pay another dentist licensed in that jurisdiction to perform a clinical dental exam on the suspect and take necessary photographs, radiographs, and dental impressions. Expenses for dental laboratory work or graphic arts presentations might be included under this section, instead of in fees. The next section in the contract concerns the expert’s qualifications. In this contract, the burden of investigating and verifying that the odontologist has the necessary qualifications is put back on the other party to the agreement. While not explicitly stated in the contract, there is an assumption that the expert has the necessary qualifications and will perform professional services to the reasonable standards of the relevant professional community. It is assumed that the expert will render his true opinion and give any testimony in good faith and that he will be able to support his opinion in court properly.

The odontologist might want to remember that, although he has “witness immunity” or possibly even “official immunity” from lawsuit by the opposing party for the content of his good-faith testimony, there have been cases where dissatisfied forensic clients sued their own expert witnesses for malpractice. In these situations, the clients did not sue the experts for the actual content of their testimony; rather, the clients generally alleged that the experts negligently performed professional services in some way and thus improperly arrived at an opinion that could not be supported adequately at trial [10,11]. The terms of engagement section spells out the important issue of how and when payments are to be made to the odontologist. It also reiterates that the attorney is responsible for the payments to the odontologist, rather than the attorney’s client. Choice of law and jurisdiction can be a very important consideration for the odontologist. For example, consider again the example where the odontologist lives in and practices dentistry in Oregon, but goes to California to perform a bitemark examination and is alleged by the ME in California to have defaulted on the contract in some way. Because the odontologist did some of the work at the morgue in California and some of the work at his office in Oregon, it could be difficult for one to decide exactly where the contract was formed and where the breach occurred: California or Oregon. Thus, it might be difficult to decide which state’s court has proper jurisdiction over this dispute. A simple provision can contract around the potentially sticky issue of jurisdiction, and the parties can agree in advance which state’s laws would apply to the contract and where a dispute would be heard in case of default. The parties might include an agreement that a dispute would be resolved in arbitration, rather than in a court of law. Remember that, in reviewing a written agreement, if changes are made to the agreement—adding some provisions or deleting others—the altered agreement will likely operate as a counteroffer, and the original offer will become void. It would be better to “hammer out” all the terms and details earlier in negotiations prior to their being reduced to a final writing. The offeror is, of course, free to agree to the counteroffer made by the offeree, but one might decline and call off the deal entirely if proposed changes are too onerous.

30.9â•…Sample Contract The following sample contract between an expert witness and an attorney is reprinted with the kind permission of Aaron Larson, Esq., Ann Arbor, Michigan, and the ExpertLaw Project® (http://www.expertlaw.com).

Contracting with the Expert Witness

Consultant Agreement This agreement is entered into between Edward Expert, the consultant, and Linda Lawyer, the client-attorney. The purpose of this agreement is to procure the services of the consultant in relation to the case of Hatfield v. McCoy, Case No. PH-004432-DO, pending before the Circuit Court for the County of Hazzard, State of Arkansas. Mr. Expert shall provide services for the client-attorney as an independent professional. Payment to Mr. Expert is not dependent upon the findings which Mr. Expert renders, nor on the outcome of any legal action, mediation, arbitration, or the amount or terms of any settlement of the underlying legal case, nor on any contractual arrangement between the client-attorney and any other person or party. Engagement fee: At the time of the execution of this agreement, the client-attorney shall tender to Mr. Expert a nonrefundable engagement fee in the amount of two thousand dollars ($2,000.00). Billings for services performed or expenses incurred shall be charged against the engagement fee until such time as it is exhausted. The client-attorney shall not identify Mr. Expert as either a testifying or nontestifying expert until such time as the engagement fee has been paid. Fees: The fees for services provided by the consultant and his staff are as follows. Consultant fees: Except as outlined herein, the client-attorney shall compensate Edward Expert at the rate of $140.00 per hour for all tasks performed under this agreement, including but not limited to analysis, calculations, conclusions, preparation of reports, and necessary travel time. Fees will be billed by the tenth of an hour, with a minimum charge for any discrete task of two tenths of an hour. For testimony at deposition or trial, the clientattorney shall compensate Edward Expert at the rate of $200.00 per hour, to be billed in hourly increments. This rate for testimony shall apply both while Mr. Expert is waiting to give testimony, whether at an office or court, and for time taken for breaks or meals, as well as for time spent actually giving testimony. Investigator fees: At times, Mr. Expert may require the assistance of his investigator, Samuel Sleuth. The client-attorney shall compensate Edward Expert at the rate of $100.00 per hour for services performed by Samuel Sleuth, with fees to be billed by the tenth of an hour. Graphic design and exhibit preparation: The client-attorney shall compensate Mr. Expert for time spent preparing graphics or exhibits at the rate of $100.00 per hour, regardless of who performs the associated services. In the event that Mr. Expert outsources the preparation of graphics or exhibits, the client-attorney shall

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reimburse Mr. Expert for the actual cost of the services, plus a five percent (5%) handling fee; however, the fee for outsourced services shall not exceed the rate of $100.00 per hour without the approval of the client-attorney. The fees outlined in this paragraph do not include the cost of materials. Expenses: Expenses incurred by Edward Expert shall be reimbursed by the client-attorney as follows: Travel by car: 38 cents per mile Travel by air or train: the actual cost of the roundtrip ticket, plus a ten percent (10%) handling fee. Expenses associated with photography, reproduction of documents and photographs, preparation of exhibits, storage of materials or evidence, and other reasonable expenditures shall be reimbursed at market rates. Lodging: For any travel of more than eighty (80) miles from Mr. Expert’s office, Mr. Expert shall be reimbursed for the cost of meals and lodging, plus a ten percent (10%) handling fee. Car rental: In the event of travel beyond the local area, Mr. Expert shall be reimbursed for the cost of a midsized rental car and any associated expenses, plus a ten percent (10%) handling fee. Unless otherwise instructed by the client-attorney, or unless refundable tickets are not available, Mr. Expert will purchase refundable tickets for any necessary travel. Should the client-attorney request that Mr. Expert purchase nonrefundable tickets in order to travel at a lower cost, or if refundable tickets are not available, the clientattorney shall reimburse Mr. Expert for the cost of any nonrefundable ticket at the rate outlined herein whether or not the ticket is used. The client-attorney may avoid the ten percent handling fee associated with certain travel expenses by arranging to purchase round-trip travel tickets directly on behalf of the expert, and by arranging for the direct payment of any car rental expense, lodging, and meal expenses by the client-attorney’s office. Qualifications: The client-attorney has had the opportunity to investigate and verify Mr. Expert’s credentials and agrees that Mr. Expert is qualified to perform the services described in this contract. Terms of engagement: The client-attorney is responsible for payments to Mr. Expert as outlined in this contract, regardless of any arrangement the client-attorney has with any party or parties he represents. Mr. Expert will issue bills on a monthly basis or whatever other interval he deems appropriate. Bills are due on receipt

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and shall be considered delinquent if unpaid more than thirty days after their date of issuance. Interest shall accrue to any delinquent balance at the maximum rate permitted by law, not to exceed 1.5% per month. In the event that a bill remains unpaid for sixty or more days after the date of issuance, Mr. Expert shall have the unrestricted right to resign from performing additional services for the client-attorney on any and all cases that Mr. Expert is working on for the client-attorney’s firm. Choice of law and jurisdiction: This agreement shall be interpreted under the laws of the State of _____________. Any litigation under this agreement shall be resolved in the trial courts of _____________ County, State of _____________. I accept the terms of this agreement: Date: _______ Date: _______

______________________________ Linda Lawyer, Client-Attorney ______________________________ Edward Expert

Consultant agreement © 2010 Aaron Larson. All rights reserved. Used with permission.

References 1. Garner, B., ed. 2001. Black’s law dictionary, 2nd pocket ed. St. Paul, MN: West Group. 2. An Act for the Prevention of Frauds and Perjuries, 29 Charles II, c.3 (1676). 3. U.S. Const. art. I, §10. 4. Tex. Const. art. I, §16. 5. Restatement of the Law of Contracts §75 (1932). 6. See Potts v. Zettel, 220 F.Appx. 559, 9th Cir. (2006). 7. Burke v. Town of Walpole, 405 F.3d 66, 1st Cir. (2005). 8. Brady v. Maryland, 373 US 83 (1963). 9. Citation omitted due to pending litigation. 10. Pitluck, H. 2005. Legal liability of an expert witness. In Bitemark evidence, ed. R. Dorion. New York: Marcel Dekker. 11. Barsley, R. 2005. Case law. In Bitemark evidence, ed. R. Dorion. New York: Marcel Dekker.

Courtroom Aids in Bitemark Evidence John P. Kenney

31

Contents 31.1 Introduction 31.2 The Problem 31.3 The Expert Witness 31.4 The Material 31.5 Courtroom Aids 31.6 Conclusion References

561 561 561 562 562 567 567

31.1â•…Introduction The use of courtroom visual aids is very significant in bitemark cases. The special skill in discerning threedimensional spatial relationships is a professional requirement for the dentist or odontologist. That skill, coupled with the forensic expertise, permits the odontologist to envision the class and individual characteristics of the offending dentition that inflicted the injury or injuries and hopefully to communicate these findings clearly to the trier of fact, be it judge, jury, or both. This chapter discusses a number of methods of evidence presentation gleaned from respected and experienced American Board of Forensic Odontology (ABFO) colleagues. It is important to remember that each bitemark case is different, with evidence presenting on the body, on foodstuff, or on inanimate objects. Each case may require some creative thinking to present the evidence clearly, to make it understandable, and to demonstrate it well. While some jurisdictions may have technical assistance available to produce courtroom aids, it usually falls to the odontologist to produce them.

31.2â•…The Problem The average jurist may at best adjudicate one or possibly two bitemark cases during an entire career on the bench (H. Pitluck, R. Barsley, G. Vale, personal communication, 2003). The average juror has a high-school education. Bitemarks on humans usually involve a heinous and violent crime. By the time the odontologist testifies, the trial will have likely run a number of days, and the juror has already seen and heard very disturbing evidence. The forensic dental expert understands the nuances of the evidence, how it was analyzed, and how to visualize the conclusions. It is up to that expert to convey the

information in as simple and straightforward a manner as possible. The purpose is to inform and educate the judge and jury on the derivation of the expert’s conclusions. Perhaps the classic case of courtroom blunder from the prosecution’s perspective is the O. J. Simpson trial, where the jury was overwhelmed by the scientific evidence and likely discounted much of it.

31.3â•…The Expert Witness A good courtroom presentation for the prosecution begins with the methods used in evidence recovery, collection, and preservation—in other words, the chain of possession or custody of the material evidence. Each collected item may eventually find its way into court, either as primary evidence or as part of an analysis (work product) that allows a forensic specialist to come to a conclusion. Like a house of cards, unless the chain of custody is preserved, it will topple. The introduction of the material at trial by the prosecution or expert will come under intense scrutiny by the defense team—namely, lawyer and expert witness. In addition, of course, the opposing expert witness focuses on the methodology, analysis, and conclusions of his or her counterpart. Defense will question the qualifications of the expert in voir dire in an attempt to “kill the messenger.” When a budget allows, a second odontologist might approach the case by different means or presentation and yet arrive at the same conclusion, thus reinforcing the client, attorney, or agency’s case. Alternate light imaging [1–3] and scanning electron microscopy (SEM) analysis [4] are fields where a second odontologist could be utilized. Given the courtroom climate today, a second opinion and testimony are recommended. A defense expert does not have to disclose either the report or the opinion in the case unless called to do so

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in cross-examination. On the other hand, knowing the expert’s opinion, defense counsel will not place him or her on the stand unless it benefits the client. Depending on the jurisdiction, a work product may not be discoverable. A work product might be considered to be materials used in arriving at a conclusion or personal notes made during the analysis of a case. In each of the methods described, the expert witness must carefully document, demonstrate, and explain the methodology used in the analysis and comparison for the trier of fact. One or several posters or diagrams or a video and/or PowerPoint presentation might be used as an aid for this purpose. The credibility of the expert witness might well hinge upon his or her ability to communicate the information. Unfortunately, the communication skills of the expert witness are not always at fault. This author has experienced a dozing juror that led to a “hung jury” despite the compelling bitemark evidence. The outcome even surprised the defense. The second trial resulted in a conviction of first-degree murder. The best method of conveying testimony is by looking at the trier of fact, be it judge or jury. Eye contact is important. Is the jury attentive? Is the information pertinent? Is the information understandable? In direct testimony the experienced expert witness is normally relaxed. In cross-examination, the expert might feel resentment, conflict, aggression, mistrust, or trepidation even bordering on hatred for the opposing attorney. This is the adversarial component of the trial. The expert witness must understand this principle and must detach personal feelings to concentrate on the message he or she is attempting to convey. The expert witness must appear impartial on cross-examination despite the fact that the opinion favors the opposing side.

31.4â•…The Material The type of evidence a forensic dentist might utilize includes photographs, dental and bitemark impressions and casts, personal notes, and the official agency report. If the victim is deceased, resected and preserved tissue is evidence or the judge just might permit photographs of it instead. Facial and oral photographs, an odontogram, dental impressions, bite registration, measÂ�ureÂ�ment of maximum bite opening, and a checklist record of evidence are collected from the suspect or the accused [5]. In addition, dental records from victim or suspect might be required. For specifics on these items, read the appropriate chapters in this textbook. Each item of evidence will be introduced individually in court. The collective regrouping of evidence for

demonstrative purposes will be introduced separately. For example, if photographs are incorporated within a chart, diagram, poster, or video, a duplicate will need first to be introduced as a court exhibit. Opposing counsel might attempt to block its introduction or its use as part of the composite (group) demonstrative aids. A favorable ruling by the judge will be needed to introduce the material at trial. Dorion reports (personal communication, 2003) on a series of four posters presented in a 1984 homicide trial. The posters measÂ�ured approximately 3 feet by 2 feet with embedded black-and-white and color photographs. The smallest photographs were in a 1:1 ratio in black and white. The posters depicted bitemark photographs of the thigh, calf, and leg of a female infanticide victim and the accused’s dental casts in standard and mirror images (FigureÂ€31.1). A fourth poster demonstrated the Dorion techniques of excision, fixation, and transillumination of bitemarks for the first time. The comparative technique of using the accused’s incisal overlays to the subcutaneous hemorrhage pattern was also used for the first time. Be prepared for any eventuality in the courtroom, because it can and will happen. Opposing attorneys have been known to damage evidence “accidentally,” such as dropping dental casts or separating overlays from photographs. Dental casts should be as neatly trimmed as ideal orthodontic models would be. There is nothing more unprofessional than dental casts that look like quickpour study models. To improve the visibility of dental models, they can be poured in a contrasting color die stone (e.g., Green Die Keen, Kerr Dental Mfg.), and with the base in a yellow or white dental stone. All models and other evidence should be clearly labeled for identification purposes. If a model box or container is available, the items therein can additionally be numbered as group evidence. A supply of Ziploc bags and bubble wrap can serve as additional protection in preserving, storing, and transporting the various impressions and models to court. Wax or Styrofoam bite registrations should also be properly preserved and stored.

31.5â•…Courtroom Aids The earliest courtroom aids for bitemark evidence relied on hand-drawn transparent acetate overlays produced from either wax bite incisal/occlusal impressions or incisal outlines of dental casts. The life-size overlays were then placed on top of the bitemark photograph for visual comparison. A one-to-one scale overlay or bitemark photograph was difficult for the expert, judge, and jury to appreciate, so often multiple life-size props were created.

(4:1/2)

Victime:

(4:1/2)

L.M.L Morsure #15-Cuisse Gauche

83-02-15

Photo par Trans-Illumination

Centre Hospitalier

83-02-17

Laboratoire de Medecine Legale

83-02-22 Morsure #15 Cuisse Gauche

Courtroom Aids in Bitemark Evidence

Victime:

Morsure #13 Jambe Gauche (Mollet)

83-02-17

Dentition

Prelevement + Fixation 83-02-25

83-02-17

Hemoragie Sous-Cutane ET Dentition Du Suspect

Photographie 83-03-16 DR.RBJ Dorion Morsure #12 Jambe Droite

83-02-17

Empreintes 83-02-23

Figure 31.1â•‡ Photographs mounted on posters for court presentation. (Courtesy of Dr. Robert Dorion.)

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Figure 31.2â•‡ Poster of perpetrator’s dentition, Aluwax, and

bitemark.

Charts and drawings with arrows and other markings (FigureÂ€31.2) were used on easels or overhead projectors. In an attempt to move from hand-drawn acetate overlays to a more precise analytical method, Rawson [6] mentions radiographic duplication of the incisal image by placing a radiopaque powder, such as barium sulfate, or amalgam filings and acrylic into the wax bite registration, irradiating the bite registration and underlying x-ray film, and then comparing it to the photographs of the injury. By reverse-printing the radiographic image, hollow volume overlays were produced for comparison [7]. Later, analog photographs created black-and-white transparencies in various magnifications (1×, 2×, 3×, etc.), which were compared to analog photographs of the bitemark at the same magnification. Other methods have utilized copying machines [7] for the production of overlays. This involved the blackening of incisal edges of dental casts and photocopying the models on acetate rather than paper. Sweet [8,9] first described a method of comparison by computer scanning dental models and bitemark photographs using Adobe Photoshop. Currently, digital images can be captured directly rather than having to scan standard photographs. As overlay techniques have changed, so have courtroom aids progressed. Stone models have been replaced by multicolored or clear acrylics [10]. Models can be articulated using simple hinge articulators or the more sophisticated ones such as Whip Mix or Hanau. It should

be noted, however, that mounting dental models on an expensive articulator might not be a wise business decision, unless reimbursement has been prearranged with the hiring party. Moreover, a personal articulator would not be returned until the end of trial, at the very earliest, or until all appeals have been exhausted. A cheaper technique of mounting stone or acrylic dental casts employs the vise grip sheet metal pliers [11]. In one court testimony, the “dramatic” effect was not lost on the jurors, who proceeded to “bite” themselves both in the jury box and room, much to the dismay of opposing attorneys. More sophisticated and adjustable pliers were developed but failed to gain general acceptance because of excessive cost. This author has used a pediatric Dentek dental form restored with multiple stainless-steel crowns and multisurface restorations as they present in the plaintiff’s oral cavity for demonstration in a malpractice case. The idea is to think creatively while preserving good taste and science. Another technique to make the evidence readily understandable by the jury is the use of a booklet for each juror to demonstrate step by step what was done. This would have to be accepted by the trier of fact and the defense to be utilized. Adequate copies for all members of the court (judge, attorneys, and jury) must be provided (Sweet, personal communication, 2009). Peter Hampl (personal communication, 2009) uses copies of photos of the dentition and the bitemark mounted on poster board, with the clear plastic (Mylar®) overlay tracing of the incisal edges of the defendant’s teeth mounted in the center with a cross-hair index. Each member of the court (judge, jury, and attorneys) has his or her own copy and can flip from the dental overlay to the bitemark. Rawson did one of the first examples of a video presentation of evidence in the mid-1980s [6]. Two cameras and a video mixer were used to wipe and fade the image of the dentition over the injury. At the time, the equipment was costly and confined to institutions with audiovisual or television production capabilities. Dorion and Gould (personal communication, 2002) and Kenney have employed various adaptations of video superimposition over the past 20 years (FiguresÂ€31.3 and 31.4). Each item of evidence is recorded and a step-by-step “storyboard” created. Video lends itself to a compelling, direct, and dynamic presentation of the comparison by moving the model or overlay over the photograph of the injury. Alternatively, the model can be “moved” over the polyvinylsiloxane replica of the injured tissue or against the resected, supported (ringed) tissue itself. As home video editing equipment became more sophisticated and reasonably priced, it became easier to produce

Courtroom Aids in Bitemark Evidence

Color Monitor

565

8MM/VHS Camcorder W/Macro Focus

Initial Edit/ Recording of Tape

Light Box S-VHS Recorder

Video Titler/ Editor

VHS Recorder

presentation. In another case, the court-Â�provided VCR malfunctioned and a fuzzy image resulted. Fortunately, this bench trial’s judge simply stated that he would review the evidence at home to determine its validity. All of the video’s content had previously been introduced separately in earlier testimony. Stimson (personal communication, 2003) in the mid-1970s created an exhibit made of orthodontic wire that contoured the buccal surfaces of the suspect’s dental casts, which could then be approximated to the bitemark photograph (FigureÂ€ 31.5). The defense attorney physically distorted the exhibit during trial and chrome cobalt castings (FigureÂ€ 31.6) had to be constructed to

Figure 31.3â•‡ Initial edit/recording of tape flow chart.

Color Monitor

8MM/VHS Camcorder W/Macro Focus Final Edit of Tape for Court

Light Box

S-VHS Recorder

VHS Recorder

Video Titler/ Editor

Figure 31.4â•‡ Final tape-editing flow chart.

courtroom presentations on videotape, adding labels, arrows, and other diagrammatic aids. Wiping between overlaid images or fading in and out demonstrated the comparison or exclusion of the suspect or accused’s dentition to the bitemark. The same superimposition technique (also called approximation) utilizes an antemortem photograph of a known person comparing it to the unknown’s skull. A refinement of the technique compares the dentition in a like manner (G. Gould, personal communication, 2003). Lastly, the superimposition technique has also been successfully used in tool mark, tire, shoe, knife, and ballistic print comparisons. A video presentation should not contain a “voice over.” While this may seem beneficial, the defense may object to voice over, the court might agree, and the presentation would then be compromised. This author has experienced the latter with a portion of a videotape (video content with “prejudicial” morgue shots). Fortunately, erasing the offending portion did not compromise the

Figure 31.5â•‡ Orthodontic wire (Courtesy of Dr. Paul G. Stimson.)

outlining

bitemark.

Figure 31.6â•‡ Chrome cobalt casting outlining bitemark on cast. (Courtesy of Dr. Paul G. Stimson.)

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Figure 31.7â•‡ Overlays on bitemark photographs.

replace the wire. Occlusal rests placed on posterior teeth stabilized the appliance. Stimson (personal communication, 2003) also suggests the following method to index overlays, be they photographic, xerographic, or computer generated. The occlusal table of a posterior tooth such as a first bicuspid on only one side of the arch is blackened, so that it is duplicated on the overlay as well as the model. Marking right and left as well makes it easier for the jurors to determine “which side is up” when watching the demonstration and later attempting to duplicate it in the jury room. In one case, Stimson (personal communication, 2009) relates that the evidence prepared for court was deemed inadmissible due to prosecutorial error. Dr. Stimson used a plastic page separator, impressed the incisal edges of the models onto the surface, and marked them in the presence of the judge and jury; these were deemed admissible. In another case, because the courtroom was too bright to visualize the evidence on screen, Aluwax© was heated with a cigarette lighter as a visual demonstration for the jury. Hampl and this author have also employed coloring the incisal edges of teeth on overlays (FigureÂ€31.7) as a substitute for tooth numbering or dental anatomical descriptors. Obviously, colorblindness negates the use of the technique for both expert and jurors. Computers, scanning devices, and digital photographs are currently used. The presence of the ABFO no. 2 scale facilitates manipulation of digital images in bitemark comparison. The proper orientation of the dental casts for bitemark comparison will contain a “flipped” ABFO no. 2 scale. Golden (personal communication, 2003) prepares sequential working images of the bite and the overlays in various positions for comparisons. He suggests an Epson printer that has a 60-inch wide format and uses continuous roll photo paper, for length, to create poster-size exemplars. The evidence unit of a large police department or county sheriff, district attorney, or state’s attorney may have such a printer available. Another option would be a local franchise offering quick

printing services; it is a good idea to choose a time when its business is slow for the processing. Scanning electron microscopy presents its own set of problems because of the “shades of gray” in the created images. It is necessary to explain clearly to the jury what SEM is, how it creates the image, and how the comparisons are made. Fade-in and fade-out and wiping the blended images can all work to demonstrate the techniques to the jury. Sometimes the simpler method of “poster and arrows” will adequately convey the correspondence between the perpetrator’s dentition and the bitemark. David (personal communication, 2003) suggests that the overlay technique is as good a method as any in demonstrating to the jury how the injury was inflicted. Courtroom presentations have undergone development in the past quarter century and are more sophisticated. Today, PowerPoint presentations are commonplace. High-resolution projectors and large-screen HDTVs are equipment necessities. Perhaps the most frequent problem mentioned is that the odontologist’s laptop has a problem “talking” to the AV equipment provided by the court. Review of the evidence presentation on the exact AV equipment to be used several days prior to testimony is important. This is particularly true if embedded video is to be used. Be aware of common problems such as video resolution settings on the computer when using a courtprovided video projector or monitor. Burning a DVD/ CD of the presentation with use of the court’s computer may be simpler. The presentation can be deposited as a court exhibit. Another caveat here is to make sure that there is a copy of the correct compatible video decoding software present on the court computer; otherwise, the PowerPoint presentation will run until one tries to present embedded video and the program will stop with only the first frame showing. According to a protocol suggested by Wright (personal communication, 2003), a copy of the CD/DVD should be provided to the court, as well as 1200-dpi prints of each slide in the program that is authenticated. Wright and Averill are developing a “streaming video”

Courtroom Aids in Bitemark Evidence

for use in PowerPoint presentations. Pixilation of the image can be problematic, particularly if one is attempting to show a dynamic bitemark comparison at macrofocus via PowerPoint. Digital analysis of bitemark evidence is state of the art. The best “cookbook” is Bowers and Johansen’s text, Digital Analysis of Bite Mark Evidence [12], which covers step-by-step procedures to follow. Some legal problems have arisen regarding digitalization and implied manipulation of evidence to “make it fit.” This author digitally enlarged and printed standard bitemark photographs to life size for court use. The public defender called into question the technique and authenticity of the photos. The original 35-mm negatives and prints were available to refute the public defender’s misguided queries. If the history palette within Photoshop is logged, the step-by-step changes from the original scanned image can be traced, duplicated, and printed. This still does not preclude the defense from arguing that the image was otherwise manipulated by addition or subtraction to make it fit. Wright (personal communication, 2003) further suggests that images be scanned and printed, not just cut and pasted on the computer so that the jury can take the evidence into the jury room and do their own testing. Bowers (personal communication 2009) suggests using 12 × 16-inch color prints mounted on Styrofoam backing in an ELMO© projector. Paintshop© images can also be embedded in the PowerPoint presentation. Dr. David Ord at UNLV relates using the evidence management software by Mideo System Technologies (http://www.mideosystems.com) to demonstrate bitemark evidence. Always be prepared for the unexpected and have a backup plan in case of equipment failure or incompatibility. Be familiar with both the software and the hardware configuration one is using. A word on courtroom demeanor should be added. Being well prepared and neatly and conservatively dressed in a dark suit or sport coat with tie will add to one’s credibility. In unfamiliar jurisdictions, the client attorney can serve as a guide. Look at the jurors while testifying. Likewise, in a bench trial, attention should be directed to the judge, the trier of fact, decision maker, and verdict renderer. Provide a business card for the court reporter, perhaps with a glossary of terms to be used. It is also helpful to spell out unfamiliar words for the court (“odontology” is probably first on the list).

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31.6â•…Conclusion The expert should present the scientific evidence creatively and understandably. He or she should educate the judge and jury on the relevant evidence to which he or she has been called to testify in a simple and straightforward manner. The expert should guide the audience from collection to analysis and comparison of evidence with precision and humility whether he or she appears for the prosecution or for the defense.

References 1. Krauss, T. C., and S. C. Warlen. 1985. The forensic science use of reflective ultraviolet photography. Journal of Forensic Sciences 30 (1): 262–268. 2. David, T. J., and M. N. Sobel. 1994. Recapturing a five-month-old bite mark by means of reflective ultraviolet photography. Journal of Forensic Sciences 39 (6): 1560–1567. 3. Golden, G. S. 1994. Alternative light source illumination in bite mark photography. Journal of Forensic Sciences 39 (3): 815–823. 4. David, T. J. 1986. Adjunctive use of scanning electron microscopy in bite mark analysis: A three dimensional study. Journal of Forensic Sciences 31 (3): 1126–1134. 5. Vale, G. L. 1985. Los Angeles County Coroner’s Office forms 21 and 21A. Rawson, R. L. Northwestern University bitemark update course. 6. Rawson, R. L., R. K. Ommen, G. Kinard, J. Johnson, and A. Yflantis. 1984. Statistical evidence for the individuality of the human dentition. Journal of Forensic Sciences 29 (1): 245–253. 7. Dailey, J. C. 1991. A practical technique for the fabrication of transparent bite mark overlays. Journal of Forensic Sciences 26 (2): 565–570. 8. Sweet, D., M. Parhar, and R. E. Wood. 1998. A computerbased production of bite mark comparison overlays. Journal of Forensic Sciences 43 (5): 1050–1055. 9. Sweet, D., and C. M. Bowers. 1998. Accuracy of bite mark overlays: A comparison of five common methods to produce exemplars from a suspect’s dentition. Journal of Forensic Sciences 43 (2): 362–367. 10. McKinstrey, R. E. 1995. Resin dental casts as an aid in bite mark identification. Journal of Forensic Sciences 40 (2): 300–302. 11. Smith, E. S. 1985. Northwestern University bitemark update course. 12. Bowers, C. M., and R. J. Johansen. 2000. Digital analysis of bitemark evidence. Indianapolis, IN: Forensic Imaging Services.

Legal Liability of an Expert Witness Haskell M. Pitluck

32

Contents 32.1 Reasoning behind Absolute Immunity 32.2 Changing Concepts Regarding Absolute Immunity 32.3 Expert Witness Immunity Specific to Dentists 32.4 What Does This Mean for the Expert? References

32.1â•…Reasoning behind Absolute Immunity

569 569 571 573 575 of that time, no court had allowed an expert witness to be sued by an adverse party over testimony [5]. However, lawsuits against friendly experts are increasing [6].

The concept of witness immunity stemmed from the old English common law to encourage witnesses to participate in litigation without fear of retaliating lawsuits from unhappy participants. In the case of Briscoe v. LaHue [1], the U.S. Supreme Court held that trial witnesses are entitled to absolute immunity for their trial testimony. The court noted that ignoring liability for testimony in a judicial proceeding could have the effect of inducing two types of self-censorship: First, witnesses might be reluctant to come forward to testify. And once a witness is on the stand, his testimony might be distorted by the fear of subsequent liability … A witness who knows that he might be forced to defend a subsequent lawsuit, and perhaps, to pay damages, might be inclined to shade his testimony in favor of the potential plaintiff, to magnify uncertainties, and thus to deprive the finder of fact of candid, objective and undistorted evidence [2].

Witness immunity has also been held to extend to pretrial statements and opinions offered in deposition testimony and advisory reports prepared in the course of litigation [3]. This is a logical extension to include those items the witness has to prepare leading up to his or her testimony. Expert witnesses have enjoyed almost universal immunity from liability as a result of their court testimony. Within the last few years, however, this immunity has been eroded to the point that experts should, and rightly so, be cautious, careful, and confident when expressing their opinions. As recently as November 2000, Mark Hansen, in an article in the American Bar Association Journal, wrote that up to that point, only eight states’ courts had addressed the issue of expert witness immunity [4]. As

32.2â•…Changing Concepts Regarding Absolute Immunity To give the reader an idea of how suits against experts are progressing, a brief history and evolution of some of the pertinent cases follow. On July 20, 1989, the Supreme Court of Washington, in the case of Bruce v. Byrne-Stevens & Associates Engineers, Inc. [7] held that an engineer who testified as an expert witness on behalf of the people suing him, at a previous trial, was entitled to absolute immunity from suit based on his testimony. The defendant miscalculated the cost of the amount of damages necessary to stabilize the plaintiffs’ property, which resulted in the plaintiff getting a judgment for about half of the necessary actual cost. This is an interesting case decision because four judges concurred in the majority opinion, one judge concurred in the result only, and four judges dissented. So, although it was a close 5–4 decision, the defendant was granted absolute immunity. However, with close decisions such as this one, one can look for a possible change of the law in the future. While the law in Washington has not changed relative to the absolute immunity from testimony, the case of Deatherage v. State of Washington Examining Board of Psychology [8], decided by the Supreme Court of Washington on December 24, 1997, held that such immunity cannot be raised as a defense to a state licensing board’s initiation of a professional disciplinary proceeding. In other words, although the expert was not subject to liability, he could still lose his license to practice. On April 9, 1992, the California Court of Appeal decided Mattco Forge Inc v. Arthur Young & Co. [9] and

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held that the litigation privilege does not shield a party’s own witness from an action by the party arising from the expert’s negligence and breach of contract. Several months later on November 24, 1992, the Supreme Court of Missouri, in the case of Murphy v. AA Mathews [10], held that witness immunity does not bar negligence suits against professional experts who agree to provide litigation-related service for compensation if the professional is negligent in providing the agreed services. Opposite to this ruling, the Pennsylvania Supreme Court held in the case of Panitz v. Behrend [11] on October 13, 1993, that Panitz was immune from civil liability even though, on cross-examination, she failed to support the position she had earlier informed the law firm she would take. On December 7, 1993, the Court of Appeals of Nebraska in Central Ice Machine Company v. Cole [12] held that “in the absence of a statute imposing civil liability, we believe the better policy to be to grant witnesses immunity from civil liability for damages resulting from statements made by them as such, and to leave the matter of liability for perjury to the criminal law” [13]. In Tyner v. State of Washington [14], on September 28, 1998, the Court of Appeals in Washington denied the state the shield of expert witness immunity wherein the plaintiff was suing the state for negligent investigation, not for negligence in providing expert testimony [15]. In the case of Dalton v. Miller [16], the Colorado Court of Appeals held on April 29, 1999, that the defendant psychiatrist was entitled to absolute immunity from civil liability for statements he made in an evidence deposition and for the contents of the report he prepared for counsel [17]. It is interesting to note that the court stated, “In so holding, we note that the liability of expert witnesses to the party or parties employing them is not at issue in this case. Our holding here is limited to suits against witnesses by parties who are adverse to those who employed the witness” [18]. The matter was remanded for trial on other issues. On October 20, 1999, in LLMD of Michigan Inc v. Jackson-Cross Company [19], the Supreme Court of Pennsylvania distinguished the case of Panitz [20] in not extending the witness immunity doctrine to professional negligence actions brought against an expert witness when the allegations of negligence are not premised on the substance of the expert’s opinion [21]. There was a dissent filed that stated that the distinction was unworkable and a radical departure from accepted law regarding witness immunity [22]. In a case of first impression, the Superior Court of Connecticut, Judicial District of New Haven, on May 17, 2000, held in the case of Pollock v. Panjabi [23] that claims in connection with an expert’s alleged failure to

provide adequate support services were not barred by witness immunity. Shortly after that decision, in the case of Rohrer v. Connelly [24], the Court of Common Pleas of Pennsylvania, Dauphin County, on July 21, 2000, cited the Pennsylvania Supreme Court in LLMD of Michigan Inc. v. Jackson Cross Co [25] to be directly on point in illustrating the distinction between unfavorable expert testimony and professional negligence in the preparation of an expert report [26] and denied the defendant’s claim for immunity from plaintiff’s claim for professional negligence. The court stated, “The sound public policies afforded by the immunities granted to lay witnesses—and even non-negligent expert testimony— will not be undermined by holding experts to the same standard of care in preparing for litigation as they would [be held] in their routine professional practice” [27]. Less than a year later, on April 12, 2001, the U.S. Court of Appeals for the Fifth Circuit, on an appeal from the U.S. District Court for the Eastern District of Louisiana in the case of Marrogi v. Howard [28], certified the following questions for decision to the Louisiana Supreme Court: Under Louisiana law, does witness immunity bar a claim against a retained expert witness, asserted by a party who in prior litigation retained that expert, which claim arises from the expert’s allegedly deficient performance of his duties to provide litigation services, such as the formulation of opinions and recommendations, and to give opinion testimony before or during trial? [29]

The Louisiana Supreme Court answered that question in the negative on January 15, 2002, and furthermore held that, as a matter of first impression under Louisiana law, witness immunity did not bar a claim against a retained expert witness asserted by a party who, in prior litigation, retained that expert, which claims arose from the expert’s allegedly deficient performance of his duties to provide litigation services [30]. Also in a case, of first impression, the Supreme Court of Massachusetts, on October 31, 2001, in the case of Boyes-Bogie v. Horwitz [31], denied the defendant’s motion for summary judgment and held that the doctrine of witness immunity does not bar a claim for negligence against an expert privately retained to provide litigation support services by the party who retained the expert in the circumstances of the case [32], which dealt with business evaluation in a divorce case. On April 26, 2002, the Supreme Court of Appeals of West Virginia, in the case of Davis et al. v. Wallace et al. [33], filed a most interesting opinion. The plaintiff,

Legal Liability of an Expert Witness

Davis, an incarcerated felon, sued many experts who were witnesses for the state in her criminal trial. She alleged that the experts negligently performed tests, negligently prepared for testimony, negligently testified, and otherwise failed to meet “standards of science and medicine as [they] existed at that time” [34]. The circuit court granted the defendants’ motion to dismiss and allowed sanctions in the amount of $8,500 for attorney fees against Davis, her next friend (one acting in her interest), and their attorney. The court found the claims frivolous in nature with no evidentiary support and that the appellants filed the lawsuit with a vexatious, wanton, or oppressive intent to intimidate the appellees regarding their testimony at any post-trial hearing in the criminal case or to seek to punish them for their testimony at the criminal trial [35]. The appellants appealed the awarding of sanctions. The appellate court reversed the sanctions in stating that some jurisdictions held expert witnesses liable in some circumstances and that, while West Virginia law is not settled in the area of expert witness immunity, at this time, they were not addressing the issue of witness immunity. The appellate court stated it was only addressing whether a trial judge abused his discretion by sanctioning a litigant and her attorney for expounding a novel cause of action that is not currently recognized in West Virginia [36]. Further, the appellate court stated that “since there is a plurality of opinions in other jurisdictions, the appellants’ claim cannot be found to be in bad faith as an assertion that cannot support a good faith argument for the application, extension, modification, or reversal of existing law” [37]. The chief justice filed a vigorous dissent and another justice filed a concurring opinion, criticizing the dissent: The unnecessarily harsh dissent is but a lengthy essay on the issue of whether there exists in West Virginia a cause of action for negligence or malpractice against forensic experts. The majority opinion clearly acknowledges that there is not a cause of action for suing an opposing party’s expert witness in West Virginia [38].

The concurring opinion went on to say: The majority merely acknowledges that there is an emerging body of case law and scholarly work that have begun to question the granting of absolute immunity to expert witnesses, often known in legal circles as “hired guns” for their in-court testimony and out-of-court preparations. Several law review articles and courts have begun to argue that it is not unreasonable to expect that expert witnesses should be held to standards of

571 their profession both in and outside of the courtroom, and several jurisdictions have permitted such lawsuits. Considering the developing trend, the appellants’ suit against the State’s expert witnesses should not be seen as frivolous. Thus this Court was within its authority to find that the trial court erred in levying sanctions [39].

32.3 Expert Witness Immunity Specific to Dentists Two cases regarding immunity of expert witnesses with reference to bitemarks are of specific interest to dentists. The first is Anthony Otero v. Allan J. Warnick, D.D.S. [40], decided by the Michigan Court of Appeals on May 12, 2000. The plaintiff, a former suspect in a murder case, appealed the circuit court’s order granting summary disposition in favor of defendant Allen J. Warnick, the chief forensic odontologist for the Wayne County Medical Examiner’s Office: In October 1994, Virginia Airasolo was sexually assaulted and murdered. Defendant performed an examination and concluded that wound pattern injuries on the body were consistent with human bitemarks. Following plaintiff’s arrest in connection with the murder, he consented to a search and allowed defendant to take impressions of his teeth and to review his dental records. In his written report to the Detroit Police Department, defendant opined that some of the bitemarks on Airasolo’s body matched plaintiff’s dentition. A warrant was issued charging plaintiff with first-degree murder and felony murder, and he was arrested and incarcerated. During plaintiff’s preliminary examination on December 13, 1994, defendant testified regarding his findings, suggesting that plaintiff was the only person in the world who could have inflicted the bitemarks on Airasolo’s body. On January 30, 1995, the Detroit Police Crime Laboratory released a supplemental report that concluded that plaintiff was excluded as a possible source of DNA obtained from vaginal and rectal swabs taken from Airasolo’s body. In April 1995, following the issuance of a favorable DNA report, plaintiff—who by that time had spent five months in jail—was released after posting a $60,000 cash bond. At about the same time plaintiff obtained his release from jail, defendant solicited a second opinion from forensic odontologist Richard Souviron of Dade County, Florida. Souviron issued a report concluding that, while the injury patterns on Airasolo’s body were consistent with human bitemarks, the details of the injuries were too indistinct to be used to include or exclude any suspect. As a result of this second opinion, the charges against plaintiff were dismissed. Plaintiff subsequently sued defendant, alleging gross negligence [41].

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“As a government employee, Warnick was immune from tort liability while engaged in governmental functions if he was acting, or reasonably believed he was acting, within the scope of his authority, unless his conduct amounted to gross negligence that was the proximate cause of the plaintiff’s injury or damage” [42]. Warnick moved for summary disposition arguing that he was entitled to absolute witness immunity; that, pursuant to the public-duty doctrine, he owed no duty to plaintiff; and that plaintiff’s claim was barred by the statute of limitations. The circuit court granted the motion, concluding that the public-duty doctrine was applicable and the defendant, therefore, owed plaintiff no duty of care [43].

The court stated: The statute specifically authorizes county medical examiners to employ non-licensed physicians to assist in the investigation of deaths if the medical examiner determines that persons with specialized qualifications and knowledge are needed to assist in that investigation. Considering this legislative scheme, we see no reason to limit the analysis … simply to the appointed county medical examiner. To the contrary, the logic … would apply to any person duly authorized by the examiner to assist in an investigation authorized and, in fact, required by the statute. … We conclude that the protection afforded a county medical examiner extends to persons employed by the medical examiner to assist in the investigation of a death. The county medical examiner here employed defendant, an odontologist, to assist in the investigation of a crime where the victim had bitemarks that might have helped establish identity of the assailant. Having been authorized by the medical examiner to assist in the investigation because of the special knowledge and experience he brought to the case, defendant’s only duty was to the medical examiner and to the state, and defendant fulfilled that duty by providing his expert opinion and testimony to aid in the investigation of the offense. Thus, under the medical examiner’s statute, defendant owed no duty to plaintiff [44].

The court went on to say that no duty was owed to plaintiff for a separate and independent reason as well: “Defendant’s role in the investigation was plainly adversarial to plaintiff’s interests and defendant’s duty as a witness at the preliminary examination was owed to the court, not to plaintiff. … We conclude that defendant would have owed plaintiff no duty even if the medical examiner’s statute was inapplicable” [45]. With regard to witness immunity, the court stated: Finally, to the extent that plaintiff’s claim is based on the theory that defendant was grossly negligent in

testifying against him at his preliminary examination, summary disposition was also proper … Because defendant was a witness testifying during the course of judicial proceedings, his statements were absolutely privileged, provided they were relevant, material or pertinent to the issue being tried … This quasi-judicial immunity applies even though defendant’s examination was performed, and his opinion developed, out of court [46].

The appellate court affirmed the dismissal of the plaintiff’s case. However, its conclusion in the opinion contains language that no expert witness likes to see and that is included here only as an instructional caution for future behavior: Accepting as true the allegations in plaintiff’s complaint, it is apparent that defendant performed his tasks with respect to the Airasolo murder in an incompetent, if not reprehensible, manner. Plaintiff ends his brief to us with an impassioned plea: “Defendant Warnick, for whatever reason, crossed the line between prosecution and persecution, turning a system of justice into a system of oppression. In so doing, he trampled upon the rights of Plaintiff and caused him enormous, horrific harm. Plaintiff now turns to you jurists, simply seeking and demanding a fair trial in his quest for a measure of justice. No self-respecting system of justice would deny him access to the courts and to our cherished jury system” [47].

In response, the appellate court stated, “We sympathize with plaintiff but conclude that regardless of how badly defendant performed his investigation and the harm that resulted, plaintiff’s claims are so clearly unenforceable as a matter of law that they cannot go to a jury” [48]. How long this will remain the law in Michigan remains to be seen. The second case is an opinion filed January 8, 2003, by the U.S. Court of Appeals for the Fifth Circuit (Eastern District) of Louisiana in the case of Anthony G. Keko v. I. F. Hingle et al. [49]. Two interlocutory appeals were brought from the district court’s decision in a 42 U.S.C 1983 action filed by Tony Keko to redress his overturned conviction of the 1991 murder of his estranged wife Louise. Keko appeals the court’s rendition of a Rule 54(b)—certified summary judgment in favor of two sheriffs and several law enforcement and prosecutorial personnel involved in obtaining the conviction. Dr. Michael H. West, whose tainted expert testimony led to the overturning of Keko’s conviction, appeals from the denial of absolute immunity. We affirm the appeal of the latter judgment [50].

Legal Liability of an Expert Witness

Keko argued on appeal that the other defendants (appellees) contributed to a constitutionally defective search warrant that, when approved by a state court judge, authorized, among other things, the taking of Keko’s dental impressions: “The dental impressions, according to Dr. West, … corresponded with bite marks found on Louise’s exhumed body. Dr. West’s evidence provided the only direct evidentiary link at trial connecting Keko to the crime” [51]. The judgment in favor of Dr. West’s codefendants was affirmed. The court stated, however, that “Dr. West’s appeal of the denial of absolute immunity is more problematic” [52]. He was not an employee of the parish or of any state or local government agency. The court went on to say: Dr. West has not contested the legal sufficiency of the claims against him. Nor has Dr. West challenged the district court’s ruling that he might be entitled to qualified immunity, but fact issues preclude its being granted at this time. Instead, and more boldly, Dr. West asserts that he is entitled to absolute immunity (a) for the expert witness report he authored, which was offered at a probable cause hearing to obtain an arrest warrant for Keko, and (b) for the research and investigative work that led to preparation of the expert report. … Dr. West argues, not without force, that the protection of absolute immunity is lost if an expert witness, whose testimonial competence derives solely from the application of his expertise to an investigation conducted by the state, may be sued for the activity that spawned his testimony [53].

The court, however, pointed out that absolute immunity applies only “within the precise confines of adversarial judicial proceedings” [54] and that the testimony in question here was not West’s trial testimony, but an ex parte probable cause hearing—not the type of judicial proceeding for which a witness’s testimony would require the full shield of absolute immunity [55]. The court determined that the case presented a question of fact as to the degree of Dr. West’s participation in the prosecution that could not be resolved on summary judgment based upon the record. The court stated: West may not have been a formal member of the prosecutorial team or responsible for final prosecutorial decisions, but his report stated that “indeed and without doubt,” the bitemarks he observed on the exhumed body of Louise Keko matched Tony’s dental impressions. Further, according to the state court, his report was critical to obtaining probable cause to arrest, he examined only Tony Keko’s dental impressions and not those of any other potential suspect, and he performed

573 his function at the behest of the sheriff’s office to assist in “identifying” the attacker. The complaining witness doctrine thus offers no defense as a matter of law to Dr. West [56].

The court concluded: The doctor also seeks absolute immunity for his pretestimonial activities in examining Mrs. Keko’s body, obtaining and examining Keko’s dental impressions and writing a report, … to the extent Dr. West’s pretestimonial activities were investigative, his immunity ought to correlate with the merely qualified immunity granted to the police for comparable activities. Thus, if, as alleged, Dr. West used shoddy and unscientific research techniques that resulted in a report critical to a baseless murder prosecution of Keko, there is no obvious reason why Dr. West should enjoy immunity greater than that of other investigators. By holding that absolute immunity does not shield Dr. West, we do not imply any opinion on the strength of his qualified immunity defense or the ultimate validity of Keko’s conspiracy allegations [57].

In effect, the court is saying that Dr. West may have immunity, but not absolute immunity, and that a determination will have to be made on a factual basis. This case is not one that an expert likes to see and is also included as an instructional caution for future behavior. Whatever the outcome, the time, trouble, and monetary expense is something with which no one would like to be involved. This case was settled after the court’s ruling. Thus, no further appeal or hearing will take place.

32.4 What Does This Mean for the Expert? It is easy to see from the chronicled cases that the law is changing. Absolute immunity for expert witnesses is no longer a sure thing. Experts should be aware of this and govern their conduct accordingly. There are arguments both for and against expert immunity. The primary argument for allowing expert immunity is as set forth in the Briscoe case earlier [58]— that is, to encourage witnesses to come forward with candid testimony without fear of reprisal. Bear in mind, however, that literally thousands of expert witnesses are being paid for their testimony. In theory, they are to aid the court in understanding the evidence; in fact, they are hired by one of the parties and, in some cases, the court itself to propound that party’s portion of the case. If their testimony or opinion is not favorable to the party who hires them, they will probably not be called

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to testify. There is also some concern that, by allowing experts to be sued, litigation will increase. The primary argument against witness immunity is also logical in that it alleges that the threat of liability will encourage experts to be more careful and accurate in their preparation and testimony. Experts are hired professionals and are paid for their work. They should be held to the same standards as anyone else. If their work is not competent, they should be held responsible. An excellent law review article on this subject is “Witness Immunity under Attack: Disarming ‘Hired Guns,’” by Randall K. Hanson in the Wake Forest Law Review [59]. It is easy to see that the law is changing when it comes to absolute immunity for expert witnesses. Although absolute immunity for experts is no longer a certain thing, it is also very important to remember that even if one has immunity from liability, one can still be subject to disciplinary proceedings within one’s state or from professional organizations’ licensing boards. One could lose one’s license to practice, even if civil liability does not apply. One could also be subject to perjury or contempt of court charges. Even if an expert witness is not civilly liable monetarily, the expert witness can still be sued. Even if the expert wins, the accompanying cost in time, trouble, and finances is not a pleasant experience. In this day and age, no one should be involved as an expert witness without malpractice insurance. Expert witnesses should check with their insurance carrier to discuss the type of insurance coverage most appropriate for their work and remember that it may not be enough to be insured by the government agency that hires them. The cases previously discussed are by no means an exhaustive list of cases regarding liability of expert witnesses. They are only selected examples to alert the reader that the law is changing and that expert witnesses should be careful, conscientious, and competent. It is interesting that, from the time that this book was first published to the writing of this updated chapter for the second edition, there have been very few reported cases dealing with suits against expert witnesses. Before proceeding, it is important to remember that cases reported and cited are only those cases that have been appealed to an appellate court, resulting in an appellate court opinion. If a case was settled, dismissed, or, for some other reason, not appealed, no published record would be available. Even so, it is surprising to this author that more cases have not been reported. That being said, experts should still be aware that absolute immunity for expert witnesses is no longer a guaranteed factor and that expert witnesses should continue to be careful, conscientious, and competent. While there have not been

many reported cases, two are worth mentioning for informational as well as instructional purposes. The first is Lambert v. Carneghi [60], decided by the Court of Appeal of the State of California First Appellate District on January 11, 2008. While little new material or theories of recovery are included, the court refused to grant immunity to a real estate appraisal expert. The case contains a good discussion of litigation privileges for experts and discusses many cases previously cited in this chapter. The second case is Pace v. Swerdlow [61], decided by the U.S. Court of Appeals, Tenth Circuit, on March 4, 2008, on appeal from the U.S. District Court for the district of Utah. The case started as a medical malpractice case that was filed in Utah state court and was dismissed. After the Utah state court dismissed the case, the plaintiffs did not seek reconsideration or appeal that decision; instead, they sued the expert for malpractice in the Utah state court. The defendant expert, a California resident, removed the case to federal court based upon diversity jurisdiction. The plaintiffs claimed that the defendant’s abrupt change of position, on the eve of trial, caused the state court to dismiss the medical malpractice case. The district court granted the defendant’s motion to dismiss, holding that the defendant’s change of position was not the proximate cause of the state court’s decision to dismiss the medical malpractice case. The federal appellate court reversed and remanded to the district court for further proceedings. The appellate court stated, “As a preliminary matter, the [district] court decided not to reach the issue of expert witness immunity because (1) it presented an issue of first impression under Utah law, and (2) the lack of proximate cause was dispositive, rendering a decision on witness immunity unnecessary” [62]. The appellate court concluded: Because the district court held that the proximate cause issue was dispositive on all seven of Plaintiffs’ claims, it never addressed the alternative grounds for dismissal— i.e., whether expert witness immunity barred Plaintiffs’ claims, or whether each of Plaintiffs’ claims failed upon independent grounds. Based on the record, it is unclear whether Plaintiffs’ complaint fails under these alternative grounds. On remand, therefore, the district court is free to determine whether expert witness immunity bars Plaintiffs’ claims—including whether that question should be certified to the Utah Supreme Court—or whether, for each of the Plaintiffs’ seven claims, the allegations in the complaint are sufficient to state a claim upon which relief can be granted [63]. We REVERSE and REMAND to the district court for further proceedings consistent with this opinion. In addition, Defendant’s motion to certify the expert witness

Legal Liability of an Expert Witness immunity issue to the Utah Supreme Court is DENIED with leave to reassert it before the district court [64].

There was a concurring opinion with a partial dissent, which also commented on “whether Utah recognizes the doctrine of absolute witness immunity, and if it does not, whether it is possible to state a claim for professional malpractice or some similar tort against one’s own expert witness” [65]. The concurring judge goes on to say, “Here, we have cause for even greater concern. Allowing this claim to march along sends the message to would-be expert witnesses: Be wary—very wary— of changing your mind, even when doing so might be consistent with, or compelled by, the standards of your profession” [66]. There is no further mention or citation of this case, so it is unknown what the district court may have done after remand. One of the plaintiffs’ counsels, Michael Lawrence, advises this author that the parties settled the case after the appellate decision (M. Lawrence, personal communication, April 23, 2010). Thus, the question of whether Utah recognizes the doctrine of absolute witness immunity was not decided by the Utah Supreme Court. In any event, this case is further warning for an expert witness to be prepared, careful, conscientious, and competent.

References 1. Briscoe v. LaHue 460 US 325, 103 S.Ct 1108 (March 7, 1984). 2. Briscoe v. LaHue 460 US 325 at page 333 (1984). 3. Moses v. McWilliams 379 Pa Sup Ct 150 at 166 (1988). 4. Hansen, M. 2000. Experts are liable too. American Bar Association Journal, Nov. 2000. 5. Hansen, M. 2000. Experts are liable too. American Bar Association Journal, Nov. 2000. 6. California, Connecticut, Missouri, Pennsylvania, and Texas have allowed litigation to proceed against friendly experts. Louisiana and Washington had held that friendly experts were absolutely immune from liability. New Jersey held that even a court-appointed expert is not immune from deviating from the accepted standards applicable to his or her profession. 7. 113 Wash.2d 123, 776 P. 2d 666 (1989). 8. 134 Wash. 2d 131, 948 P.2d 828 (1997). 9. 5 Cal. App 4th 392 (1992). 10. 841 S.W. 2d 671 (1992). 11. 429 Pa. Super. 273, 632 A.2d 562 (1993). 12. 2 Neb. App.282, 509 N.W. 2d 229 (1993). 13. 2 Neb. App.282 at 288 (1993). 14. 92 Wash. App. 504, 963 P.2d 215 (1998). 15. 92 Wash. App. 504 at 513 (1998). 16. 984 P.2d.666 (1999). 17. 984 P.2d 666 at 669 (1999).

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18. 984 P.2d 666 at 669 (1999). 19. 559 Pa.297, 740 A. 2d 186 (1999). 20. 429 Pa. Super 273, 632 A. 2d 562 (1993). 21. 559 Pa.297 at 306 (1999). 22. 559 Pa 297 at 308 (1999). 23. 47 Conn.Supp. 179, 781 A.2d 518 (2000). 24. 48 Pa. D.& C. 4th 76 (2000). 25. 559 Pa. 297, 740 A.2d 186 (1999). 26. 48 Pa. D. & C. 4th 76 at 83 (2000). 27. 48 Pa. D. & C. 4th 76 at 85 (2000). 28. 248 F. 3d 382 (2001). 29. 248 F. 3d 382 (2001). 30. 2001–CQ-1006 (La. 1/15/02), 805 S. 2d 1118 (2002). 31. 2001 WL 1771989 (Mass. Super.), 14 Mass L. Rptr 208 (2001). 32. 2001 WL 1771989 (Mass. Super.), 14 Mass L. Rptr 208 (2001). 33. 211 W. Va 264, 565 S.E. 2d 386 (2002). 34. 211 W. Va 264, 565 S.E. 2d 388 (2002). On September 15, 1997, Marybeth Davis was convicted of the attempted poisoning by insulin of her son and the murder of her daughter by caffeine. State v. Davis, 205 W. Va. 569, 519 S.E. 2d 852 (1999). 35. 565 S.E. 386 at 388 (2002). 36. 565 S.E. 386 at 391 (2002). 37. 565 S.E. 386 at 391 (2002). 38. 565 S.E. 386 at 398 (2002). 39. 565 S.E. 386 at 388, 399 (2002). 40. 241 Mich. App. 143, 614 N.W. 2d 177 (2000). Appeal denied by Michigan Supreme Court 463 Mich. 903, 618 N.W. 2d 771 (2000). 41. 614 N. W. 2d 177 at 178–179 (2000). 42. 614 N. W. 2d 177 at 179 (2000). 43. 614 N. W. 2d 177 at 179 (2000). 44. 614 N. W. 2d 177 at 181–182 (2000). 45. 614 N. W. 2d 177 at 182 (2000). 46. 614 N. W. 2d 177 at 182 (2000). 47. 614 N. W. 2d 177 at 182 (2000). 48. 614 N. W. 2d 177 at 182 (2000). 49. 318 F. 3d 639 (2003). 50. 318 F. 3d 639 at 641 (2003). 51. 318 F. 3d 639 at 641 (2003). 52. 318 F. 3d 639 at 642 (2003). 53. 318 F. 3d 639 at 642 (2003). 54. 318 F. 3d 639 at 642–643 (2003). 55. 318 F. 3d 639 at 643 (2003). 56. 318 F. 3d 639 at 643–644 (2003). 57. 318 F. 3d 639 at 644 (2003). 58. Briscoe v. LaHue 460 US 325, 103 S. Ct. 1108 (1984). 59. Hanson, R. K. 1996. Witness immunity under attack: Disarming “hired guns.” Wake Forest Law Review 31:497. 60. 158 Cal. App. 4th 1120, 70 Cal. Rptr. 3d 626 (Cal. App.1 Dist. 2008), review denied (Apr 23, 2008). 61. 519 F. 3d 1067 (10th Cir. (Utah) 2008). 62. 519 F. 3d 1067 (10th Cir. (Utah) 2008) Paragraph 36. 63. 519 F. 3d 1067 (10th Cir. (Utah) 2008) Paragraph 54. 64. 519 F. 3d 1067 (10th Cir. (Utah) 2008) Paragraph 55. 65. 519 F. 3d 1067 (10th Cir. (Utah) 2008) Paragraph 61. 66. 519 F. 3d 1067 (10th Cir. (Utah) 2008) Paragraph 64.

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Wrongful Convictions and Erroneous Bitemark Opinions Iain A. Pretty C. Michael Bowers Contents 33.1 33.2 33.3 33.4

Wrongful Convictions and the Nature of Innocence The Anatomy of a Wrongful Conviction Bitemarks and Wrongful Convictions The Innocence Project/Network 33.4.1 Erroneous Bitemark Opinions Overturned by DNA Evidence 33.4.1.1 Willie Jackson 33.4.1.2 Ray Krone 33.4.1.3 Calvin Washington 33.4.1.4 James O’Donnell 33.4.1.5 Dan Young, Jr., and Harold Hill 33.4.1.6 Kennedy Brewer 33.4.1.7 Levon Brooks 33.4.1.8 Robert Lee Stinson 33.4.1.9 Roy Brown 33.4.1.10 William Richards 33.5 Conclusion References

33.1â•…Wrongful Convictions and the Nature of Innocence Wrongful convictions are a feature of all judicial systems; the need for appeals clearly underlies this truth. Such convictions can be placed into two broad categories: 1. The defendant is guilty of the accused crime, but breaches within the prosecutorial court processes render the convictions improper. This would also include failures of defense council to represent clients adequately. 2. The defendant is innocent of the crime and therefore, in the presence or absence of procedural irregularities, the court has failed to reach the correct verdict. Much effort is placed on the second group of defendants; indeed, the innocence movement has been formed in order to protect and defend such individuals [1]. However, many legal scholars will argue that the first group are as important because corrections to the adversarial system

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derived from challenges to the first group’s convictions will impact those in the second [2]. This chapter is concerned with the processes in the U.S. legal system; however, it would be naive to assume that the issues described are limited to that country’s courts. It can be extrapolated that any adversarial judicial system is likely to exhibit the same weaknesses in the defense of innocence and the failure to uphold, protect, and develop its rules and regulations to protect defendants. Such failures are always more critical in jurisdictions where the death penalty is a possible sentence because there is no appeal against procedural failures, aberrant forensic testimony, or incompetent lawyers from the grave [3].

33.2â•…The Anatomy of a Wrongful Conviction Wrongful convictions are analogous to commercial airline disasters: They are rarely the result of a single failure of a system or check [1,3]. A series of complex interactions

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occur and are often compounded by each other. A wealth of resources and research has been undertaken on such convictions. Some work has used real cases and has worked retrospectively to assess the reasons behind the failures. Other researchers have used “mock” courts in which testimony is supplied to a jury in order to assess it impacts. There are common threads throughout the research: Defendant demographics. Defendants in wrongful convictions—especially capital cases in the United States—are frequently poor and often African American [3]. An example of this comes from Philadelphia, where the odds of receiving the death penalty were nearly four times higher if the defendant was black [4]. Such indigent defendants can find themselves poorly represented by either incompetent or inexperienced lawyers. Eyewitness identification. Whether using photo arrays or live line-ups, such identifications are often prone to bias; a wealth of research evidence suggests that, in particular, inter-racial identifications are especially prone to error [5–7]. Indeed, the Innocence Project believes that this is the leading cause of wrongful convictions in the U.S. system today [8], accounting for over 75% of the convictions subsequently overturned by DNA. Use of informants. Due to the incentives provided to such individuals, there is often considerable bias, sometimes resulting in false and misleading testimony. This is especially the case with so-called jailhouse informants and accomplice witnesses. Considerable effort has been made in various jurisdictions to limit the use of such informants or to issue specific instructions to juries [9], although their use still permeates the U.S. and other judicial systems [10]. False confessions. It is often difficult for juries to understand why someone would confess to a crime that he or she has not committed. But it happens. One study reported that, of 68 DNA exonerations, 15 defendants had confessed to the crime [1]. There are complex reasons for such false confessions, many of which are based on the premise that an innocent person, during police interrogation, will move from a position of confidence in his or her innocence and the system of justice to protect this through to hopelessness based on a desire to limit any penalty [11,12]. Ineffective assistance of defense council. This is often linked to the first point; poor defendants often receive overworked and underqualified defense

councils who are ill equipped to deal with the complexities of representing an innocent client. There is a perverse contradiction in the judicial system: Those who are guilty of crimes with their knowledge of events leading up to and subsequent to the act are often better placed to assist their council in their defense (i.e., there are no surprises). Innocent clients are, by definition, not party to many of the nuances of the crime and thus offer little assistance [1,3]. A range of legal arguments surround an individual’s right to “effective counsel”; in his excellent text on the subject, Dow suggests that this simply may mean an individual with a bar license and a pulse [13]. Expert witness testimony and forensic science errors. The gatekeeper function of the judiciary and the use of cross-examination to prevent and reveal errors in expert witness testimony have clearly failed many individuals; some instances are described in detail later in the chapter. It is the view of many legal scholars that this continues to take place and that powerful but error-prone expert witness testimony should be carefully examined, vetted, and regulated [3,14]. Many articles argue the relative merits of the different gatekeeper regulations (e.g., Daubert or Frye); however, others will argue that the framework is irrelevant because the courts are simply failing to engage in any form of assessment [15]. It is this last point—the nature of forensic science and its use in the criminal justice system, its deployment by the judicial system, its regulation, validation, and scientific basis—that formed the basis of the National Academy of Sciences (NAS) report on forensic science [14]. Reactions to this report are described elsewhere within this edition; the focus of this chapter is the role that bitemarks played in wrongful convictions.

33.3 Bitemarks and Wrongful Convictions In 2006 a legal review was published that was written by odontologists rather than lawyers [16]. Examining 103 cases, the authors identified the following major trends within the appeals process relating to bitemark evidence: • Bitemark evidence not sufficiently reliable or accepted • Arguments regarding the uniqueness of the human dentition

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• • • •

Constitutional arguments Inflammatory photographs Inaccuracy of techniques and errors in protocol Use of historical bitemarks and previous biting behavior • Funds for defense witnesses • Objections pertaining to witness credibility As described earlier, it is important to understand that bitemark evidence, while in many cases pivotal to the conviction, was presented within the judicial framework, which is subject to the other elements of challenge listed previously. That is, bitemark evidence is not supplied in a vacuum. It exerts influence on the trier of fact in combination with all other evidence and processes [1]. Bitemark evidence has been associated with wrongful convictions in a number of different guises, some of which are described within the case examples later in this chapter. However, it is clear that the following trends can be determined: • Odontologists have provided testimony positively identifying biters from injuries with minimal forensic detail. A recent publication describes the relationship between the forensic significance of bitemarks and the probability of expert disagreement. The authors found a strong link between bitemarks with less detail of the biter and expert disagreement [17]. • Odontologists have misidentified injuries as bitemarks. Arguably, some odontologists are underqualified, poor practitioners of the science; however, this should not affect the basis of the science itself, but rather their practice of it. • There have been differences in evidence and conclusion thresholds; it is clear from the appellate rulings that odontologists have differing views as to the certainty that can be applied to conclusions in relation to bitemark evidence. Some believe that bitemarks should only be used for exclusion; others feel that it is possible to identify a biter positively [16]. It is clear that bitemark evidence and the research that underpins it have significant steps to take in order to meet the requirements of Daubert [18], if applied, as well as the criticisms within the NAS report [19]. However, not only does the discipline need to address these issues but also the law and those who practice it need to ensure that the judicial safeguard against aberrant testimony— the cross-examination—is dutifully applied. It is the confluence of the failures of both of these systems— the correct underpinning of a research base to support

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bitemark evidence and the failure of lawyers to engage in robust and informed cross examination—that leads to increased risk of wrongful conviction [2,13]. It is also clear that the odontological community must readily accept the research evidence as it develops. While all new findings must be scrutinized for their scientific integrity and study design, there has been an anecdotal reluctance for practitioners to accept findings that might contradict their views or challenge the status quo [20]. The new research described in Chapters 20–23, inclusively of this edition, suggests that the research community is actively involved in developing the science; it will be interesting to determine whether such findings are presented to testifying odontologists at cross-examination and whether the certifying boards will recognize their importance.

33.4 The Innocence Project/Network Over 200 wrongful convictions have been identified and remedied over recent years—typically, utilizing postconviction DNA testing and litigation [21]. A group specializing in this work, the Innocence Project, was created by defense lawyers Barry Scheck and Peter Neufeld in 1992 with the aim of creating “a national litigation and public policy organization dedicated to exonerating wrongfully convicted people through DNA testing and reforming the criminal justice system to prevent future injustice” [21]. The movement has since spread across the United States and many law schools now host their own innocence projects. The movement has also spread to Canada, the United Kingdom, Australia, and New Zealand; each is dedicated to proving the innocence of wrongly convicted people through the use of DNA testing after conviction and the reform of criminal justice systems to prevent future injustice [22]. As of January 21, 2010, 249 defendants previously convicted of serious crimes in the United States had been exonerated after conviction by DNA testing. Almost all of these convictions involved some form of sexual assault and approximately 25% involved murder [21]. On February 4, 2010, Innocence Project client Freddie Peacock became the 250th person exonerated through DNA testing in the United States [22]. 33.4.1 Erroneous Bitemark Opinions Overturned by DNA Evidence To date, in 10 criminal cases in the United States with a bitemark component, individuals had been convicted and subsequently exonerated. The 10th case of judicial

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exoneration decree is as of this writing being appealed by the San Bernardino district attorney. Descriptions of these cases are provided by the New York and California Innocence Projects [22]. These give insight into the faulty use of bitemark identification, analysis, and/or testimony resulting in erroneous convictions. The authors have been actively involved in five of these exoneration cases. Several others are currently being examined by both the Innocence Project and odontologists. 33.4.1.1 Willie Jackson DNA testing exonerated Willie Jackson in 2006 and implicated his brother in a Louisiana rape. The victim identified Jackson as the assailant in a photo array and also in a live line-up. Eyewitness identification is often associated with wrongful convictions and is an area of increased scientific and judicial scrutiny. Curiously, his brother had also appeared in a line-up but was not identified by the victim. The prosecution had presented evidence of a forensic dentist, who testified that bitemarks on the victim matched Willie Jackson’s teeth. Just days after Jackson was convicted in 1989, his brother confessed to the crime but was not charged. Sixteen years later, Jackson was released based on DNA test results. In addition, a second, independent odontologist argued that the earlier odontological analysis was incorrect and that the bitemarks actually matched Jackson’s brother. His brother was already serving a life sentence for an unrelated rape [23]. 33.4.1.2 Ray Krone Ray Krone was convicted, based largely on bitemark analysis, of murdering a Phoenix bartender and sentenced to death plus 21 years. Krone’s case became known as that of the “snaggle-tooth killer” due to a senior forensic dentist’s saying that his crowded teeth matched the bitemarks on the breast and neck of the murder victim. She had been fatally stabbed and the perpetrator left little physical evidence other than a bitemark, which became a crucial component of the trial. This case had no fingerprint evidence or semen, and the blood type at the scene matched the victim’s type, as did the saliva. First convicted in 1992, Krone won a retrial in 1996; he was convicted anew, mainly on the same prosecution expert’s bitemark testimony, despite the fact that four senior dental expert witnesses for the defense claimed that Krone could not be the bitemark perpetrator. His death sentence, however, was reduced to life in prison. DNA analysis was available in 1990, but it was not until 2002 that Krone was released after DNA testing proved that he could not have been the perpetrator. Instead, saliva and blood found on the victim matched a convicted rapist already incarcerated [23].

33.4.1.3 Calvin Washington Calvin Washington was convicted of murder and sentenced to life in prison in Texas in 1987. It was alleged that Washington, either acting alone or with another male, Joe Sidney Williams, robbed, raped, and murdered the victim. A dental expert witness testified that bruises on the victim’s body were bitemarks and that these injuries matched Williams’s teeth. A jailhouse informant, later considered unreliable, claimed that he heard Washington and Williams make incriminating statements when he walked by their hotel room one night. The prosecution also produced evidence that the defendants were in possession of the victim’s car and had sold items belonging to the victim. Both Williams and Washington were convicted. Williams’s conviction was overturned on multiple legal and scientific grounds, including DNA profiling of an unknown male. The prosecution declined to retry him. Washington served 13 years in prison before DNA test results exonerated him in 2001. Testing also showed that fluids taken from the victim did not come from Washington, but rather from another man, since deceased [22]. 33.4.1.4 James O’Donnell James O’Donnell was convicted of attempted sodomy and second-degree assault. Again, eyewitness identification was employed in both a photo array and live lineup. A second eyewitness failed to identify him positively. A strong alibi was presented by his girlfriend, now wife, and her son, but prosecutors discounted this. An injury to the victim’s hand was said to be a bitemark and an odontologist stated that the injury was “consistent with” O’Donnell’s teeth. Based on the eyewitness testimony and the bitemark evidence, he was convicted. Later, DNA testing was undertaken on fingernail scrapings and saliva recovered from the bitemark, which proved that O’Donnell was not the perpetrator. He was released in April 2000 [23]. 33.4.1.5 Dan Young, Jr., and Harold Hill Dan Young and Harold Hill spent 12 years in prison before DNA testing proved that they could not have been responsible for a murder in Chicago. Their convictions were based upon a confession, frequently a feature of wrongful convictions, and bitemark testimony that their teeth were similar to bitemarks on the victim. An independent odontologist prepared a report in this case stating that the injury was not suitable for comparison due to a number of postmortem artifacts caused by a fire, apparently set to confound body identification and forensic recovery. DNA testing was undertaken from the

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victim’s clothing and this came back negative for Dan Young’s and Harold Hill’s profiles. The profile contained a mixture of two unknown men [23]. Seven defense dental experts in this case did get it correct. 33.4.1.6 Kennedy Brewer Brewer was arrested in Mississippi in 1992 and accused of murdering his girlfriend’s 3-year-old daughter. He was ultimately convicted of this crime and sent to death row. The prosecution’s case was based largely on bitemark evidence that was initially detected by the medical examiner and subsequently analyzed by an odontologist. This analysis described some 19 bitemarks from the maxillary dentition alone on the victim’s body that “indeed and without doubt” matched Brewer’s maxillary teeth. The defense expert stated that the injuries were unlikely to be bitemarks but rather postmortem artifacts caused by animal activity in the creek where the body had lain for some time before discovery. In 2001 DNA testing was undertaken on semen samples previously recovered from the victim’s body and these demonstrated that Brewer’s DNA did not match. This led to his conviction being vacated in 2002, but the prosecution intended to retry Brewer. An international panel of odontologists produced a consensus report on the injuries categorically stating that these were not bitemarks of human origin and hence any comparison to Brewer’s teeth was fundamentally flawed. Additional evidence to support this was produced by John R. Wallace, a forensic entomologist, who was able to demonstrate that the injuries to the victim’s body, wrongfully identified as bitemarks, were caused by crayfish activity within the creek where the body was discovered. In 2008 Brewer was released some 15 years after his first wrongful conviction. An individual who was a suspect in the original investigation, but not pursued, has since confessed to the crime [23]. In this case, the defense expert witness was shown to have reached the correct conclusion that these injuries were not bitemarks and hence any comparisons to a suspect’s dentition were inappropriate. Despite this, the prosecution’s expert’s evidence was accepted, hence demonstrating a potential failure in the cross-examination process to reveal the inadequacies of the prosecution’s evidence. In the Brewer case, both experts were board certified. The defense expert witness did get it correct. 33.4.1.7 Levon Brooks Levon Brooks was cleared of all charges relating to a heinous child murder for which he served 15 years in prison. Brooks was sentenced to life in prison for the 1992 murder of his ex-girlfriend’s 3-year-old daughter after false forensic testimony implicated him in

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the crime. Brooks’s case is intimately linked to that of Kennedy Brewer: Both shared common features that were not investigated. DNA testing on evidence from the crime scene in Brewer’s case implicated another man in the crime. The DNA profile matched a local man, who later confessed to killing both children. The DNA testing, combined with the confession, led to the release and exoneration of Brewer and Brooks [23]. It is not clear whether bitemarks were involved in this case; rather, the cases are linked by a common suspect, and one of the murders could have been avoided with more effective police work. There is no mention as to whether there were dental expert witnesses. 33.4.1.8 Robert Lee Stinson Prosecutors did not seek a new trial in the case of Robert Lee Stinson, who served more than 23 years in prison for a murder he did not commit. The University of Wisconsin Innocence Project began working on Stinson’s case in 2005 and obtained the DNA testing that proved his innocence. Stinson was convicted and sentenced to life in prison for the murder of a 62-yearold woman in Milwaukee, Wisconsin. His conviction was based, in part, on the testimony of two forensic bitemark analysts, who said bitemarks on the victim’s body matched Stinson’s teeth. One of the experts testified that the bitemarks “had to have been made by teeth identical” to Stinson’s and that there was “no margin for error in this.” The other called the bitemark evidence “overwhelming” and said, “There was no question there was a match.” DNA testing conducted in the case at the request of the Wisconsin Innocence Project found a male DNA profile in areas of the victim’s sweater that had tested positive for saliva. The profile did not match Stinson, proving that another person bit the victim [23]. 33.4.1.9 Roy Brown Roy Brown’s case presents an interesting misuse of bitemark evidence as well as prosecutorial misconduct. Convicted in 1991 of murder, he spent 15 years in prison during which time he suffered from liver disease and was in need of a transplant. As an inmate, he was ineligible for such treatment. Brown’s conviction was secured, in part, by bitemark evidence. However, this evidence was provided by a local dentist, who was not board certified and had no formal training in bitemark analysis. A further twist is that a qualified odontologist, with appropriate qualifications in bitemark analysis, had provided an opinion that Brown could be excluded as the biter. The prosecution ignored this report and commissioned the second, nonexpert report, which indicated that Brown was the biter. Brown obtained details of the first report that

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excluded him under the Freedom of Information Act. He was able to identify the person responsible for the crime, an individual named Barry Bench. Brown wrote to Bench stating that DNA evidence would prove his involvement in the crime. Bench committed suicide 5 days after receiving the letter and, in 2007, DNA testing proved Bench’s guilt and Brown’s innocence. Soon after his release Brown underwent liver transplant surgery and lives today. This case demonstrates the value of bitemark evidence. An experienced, trained, and appropriately qualified odontologist correctly excluded Brown as the biter in the case, yet prosecutorial misconduct led to the wrongful conviction by the use of nonexpert testimony. The Brown case demonstrates the complex interplay between forensic science, the prosecutorial arm of the judicial system, and the court that should have identified that the bitemark witness was inappropriately qualified. Such convictions are rarely the result of a single failing of the system; innocence is no guarantee against conviction. 33.4.1.10 William Richards California Innocence Project client William Richards remains in the custody of the San Bernardino SheriffCoroner Department, despite his exoneration in the murder of his wife, Pamela, and his release from the California Department of Corrections. Superior Court Judge Larry W. Allen refused to release Richards pending the district attorney’s appeal of the decision reversing his conviction. Instead, Allen reduced his bail to $750,000, an amount that Richards cannot meet because he was wrongfully convicted and has been incarcerated for the past 16 years. The appeal process is expected to last 1 year or more, during which time Richards will be held in local custody. Depending on the outcome of that process, the district attorney may retry Richards. Finding that new evidence points “unerringly to innocence,” Judge Brian McCarville reversed Richards’s 1997 conviction of murdering his wife in their Hesperia, California, home. Richards was convicted for the 1993 murder after two trials ended in hung juries. Although previously in remission, Richards was diagnosed with a second occurrence of prostate cancer in October 2008. Due to the limitations of the prison facility, Richards has been denied access to the advanced treatment recommended by his physician. “Mr. Richards may die in prison, even though he has been proven to be innocent by a California court,” said Justin Brooks, director of the California Innocence Project. “We are extremely disappointed that Judge Allen could not recognize the injustice in keeping an

innocent man behind bars.” The California Innocence Project has petitioned the California Courts of Appeal to grant Richards’s release pending the resolution of the appeal of reversal [24].

33.5 Conclusion As a number of legal and scientific commentators have observed, bitemark analysis has not passed rigorous scientific scrutiny [15,25]. Until recently, the literature did not go far in disputing that claim. Definitive research is now identifying factors responsible for the incredibly complicated subject of bitemark fabrication, as is this current edition. Some former concepts are being validated and others invalidated [26–30]. These developments aim to address the deficiencies clearly articulated by the NAS report [19]. While forensic science clearly has a role to play in assisting justice, it alone cannot be held responsible for the failures of a judicial system that, at its heart, relies upon the flawed belief that witness crossexamination is an effective protection against aberrant expert testimony. A combination of improvements in scientific method, the development of a thorough evidence base, and the reformation of the criminal justice system is required to ensure that defendants are not wrongfully convicted. Moreover, education of the judiciary and lawyers in forensic sciences, as well as certification of expert witnesses, will go a long way in improving the system.

References 1. Scheck, B., P. Neufeld, and J. Dwyer. 2001. Actual innocence. New York: Signet. 2. Dow, D. R. 2010. The autobiography of an execution. New York: Hachette Book Group. 3. Westervelt, S., and J. Humphrys. 2001. Wrongly convicted: Perspectives on failed justice. New York: Rutgers University Press. 4. Dieter, R. C. 1998. The death penalty in black & white: Who lives, who dies, who decides. Death Penalty Information Center. 5. Heaton-Armstrong, A. 1995. Eye-witness testimony and judicial studies. Medicine Science and Law 35 (2): 93–94. 6. Zajac, R., and N. Henderson. 2009. Don’t it make my brown eyes blue: Co-witness misinformation about a target’s appearance can impair target-absent line-up performance. Memory 17 (3): 266–278. 7. Clark, S. E., and R. D. Godfrey. 2009. Eyewitness identification evidence and innocence risk. Psychonomic Bulletin Review 16 (1): 22–42.

Wrongful Convictions and Erroneous Bitemark Opinions 8. The Innocence Project. 2009. Eyewitness misidentification. [cited 2010 26/04/2010]; available from http://innocenceproject.org/understand/EyewitnessMisidentification.php 9. Neuschatz, J. S. et al. 2008. The effects of accomplice witnesses and jailhouse informants on jury decision making. Law and Human Behavior 32 (2): 137–149. 10. Pretty, I. A., and D. J. Sweet. In press, 2010. A paradigm shift in bitemark analyses. Forensic Science International. 11. Leo, R. A. 2009. False confessions: Causes, consequences, and implications. Journal of American Academy of Psychiatry and Law 37 (3): 332–343. 12. Kassin, S. M., and K. Neumann. 1997. On the power of confession evidence: An experimental test of the fundamental difference hypothesis. Law and Human Behavior 21 (5): 469–484. 13. Dow, D. R. 2005. Executed on a technicality—Lethal injustice on America’s death row. Boston: Beacon Press. 14. The National Academy of Sciences. 2009. Strengthening forensic science in the United States: A path forward. Washington, D.C.: National Academies Press. 15. Beecher-Monas, E. 2009. Reality bites: The illusion of science in bitemark evidence. Cardozo Law Review 30 (4). 16. Pretty, I. A., and D. J. Sweet. 2006. The judicial view of bitemarks within the United States criminal justice system. Journal of Forensic Odontostomatology 24 (1): 1–11. 17. Bowers, C. M., and I. A. Pretty. 2009. Expert disagreement in bitemark casework. Journal of Forensic Sciences 54 (4): 915–918. 18. Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993). 19. Kaye, D. H. 2010. The good, the bad and the ugly: The NAS report on strengthening forensic science in America. Science & Justice 50 (1): 8–11. 20. Pretty, I. A. 2006. The barriers to achieving an evidence base for bitemark analysis. Forensic Science International 159 (Suppl 1): S110–120.

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21. Collins, J. M., and J. Jarvis. 2009. The wrongful conviction of forensic science. Forensic Science Policy & Management: An International Journal 1 (1): 17–31. 22. The Innocence Project. 2008. About the Innocence ProÂ�ject [cited 2010 26/04/2010]; available from http:// www.â•‰â•‰â•‰â•‰Â�innocenceproject.â•‰org/about/ 23. The Innocence Project. 2010. Cases where DNA revealed that bite mark analysis led to wrongful arrests and convictions. [cited 2010 18/03/2010]; available from http:// www.innocenceproject.org/Content/394.php 24. Project, T. I. 2010. Exonerated man remains in prison, denied needed cancer care. [cited 2010 26/04/2010]; available from http://www.cwsl.edu/main/default.asp?â•‰ nav=news.asp&body=news/richards_denied_care.asp 25. Pretty, I. A., and D. Sweet. 2001. The scientific basis for human bitemark analyses—A critical review. Science & Justice 41 (2): 85–92. 26. Bush M. A., R. G. Miller, P. J. Bush, and R. B. J. Dorion. 2009. Biomechanical factors in human dermal bitemarks in a cadaver model. Journal of Forensic Sciences 54 (1): 167–176. 27. Miller, R. G., P. J. Bush, R. B. J. Dorion, and M. A. Bush. 2009. Uniqueness of the dentition as impressed in human skin: A cadaver model. Journal of Forensic Sciences 54 (4): 909–914. 28. Bush, M. A., K. Thorsrud, R. G. Miller, R. B. J. Dorion, and P. J. Bush. 2010. The response of skin to applied stress: Investigation of bitemark distortion in a cadaver model. Journal of Forensic Sciences 55 (1): 71–76. 29. Bush, M. A., H. I. Cooper, and R. B. J. Dorion. 2010. Inquiry into the scientific basis of bitemark profiling and arbitrary distortion compensation. Journal of Forensic Sciences 55 (4): 976–983. 30. Desranleau, S., and R. B. J. Dorion. In press, 2011. Bite marks: Physical properties of ring adhesion to skin— Phase 1. Journal of Forensic Sciences.

Contentious Issues

XII

Reliability of Bitemark Analysis Iain A. Pretty

34

Contents 34.1 Introduction 34.2 What Is Reliability? Statistical Definitions 34.2.1 Reliability 34.2.2 Validity 34.2.3 Accuracy 34.2.4 Sensitivity and Specificity 34.2.5 Receiver Operator Characteristics 34.2.6 Area under the Curve 34.2.7 Positive and Negative Predictive Values 34.3 Reliability, Daubert, and the Law Courts: The New Gatekeepers of Forensic Science? 34.4 The Research 34.4.1 Whittaker, 1975 34.4.2 Pretty and Sweet, 2001 34.4.3 The ABFO Bitemark Workshop, Arheart and Pretty, 2001 34.4.4 Dorion and Roberts, 2001 34.4.5 Pretty and Bowers, 2009 34.5 Statistics and Bitemarks 34.6 Summary References

34.1â•…Introduction The detection, observation, collection, and analysis of bitemarks have been thoroughly described in the previous chapters. Guidelines exist for both the novice and expert to ensure that protocols are followed and that a uniformity of approach is achieved [1,2]. However, the analysis of bitemarks following evidence collection is the sole responsibility of the odontologist. An analysis technique that is accurate is selected, and it is applied, using prior knowledge, to current material [3,4]. The results form the basis of the conclusions contained within the written report. Within the modern judicial system, the previously blind acceptance of science has evolved into an equally skeptical view. Scientists from all disciplines who present evidence within the judicial system must be prepared to defend techniques and demonstrate sound scientific principles upon which their conclusions are based. Nowhere is it more so than in the United States, where the Daubert ruling enlisted the judge as the scientific “gatekeeper” whose function is to assess the scientific integrity of the evidence (rather than the individual presenting that evidence) and determine whether it should be heard. While the U.S. judiciary has taken the

587 588 588 588 588 588 590 591 591 591 592 592 593 594 596 596 596 597 598

lead in this area, examples can be found within commonwealth and European laws mirroring the spirit of the Daubert philosophy. Also in the United States, through the National Academy of Sciences (NAS) report, Strengthening Forensic Science in the United States: A Path Forward [5], the issue of the integrity of forensic science was again questioned. Impression evidence is singled out in particular as strong recommendations are made to further research in support of reliability, validity, and accuracy (tool mark, fingerprint, footprint, document examiner, bitemark) of these disciplines. The NAS report will be further discussed in the next chapter. Returning to the legal framework, Daubert states that individuals presenting scientific evidence based upon the application of tests, assessments, or other analyses should be able to prove, preferably by citing peer-reviewed research, the validity, reliability, and accuracy of such examinations. By doing so, the trier of fact (normally the jury) is able to afford the testimony the appropriate weight. Indeed, should a particular test or system prove to be too unreliable or have a hiatus of supporting research demonstrating efficacy, it is possible that evidence based upon such tests may not be admissible in court. A common example of such science would be the polygraph test.

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In essence, the Supreme Court is stating that expert testimony should be based on scientific methods, and while flexible and somewhat liberal interpretations of this are necessarily required, it does not absolve the forensic scientist from basing opinions and conclusions on science, peer-reviewed evidence, and methodologies. Indeed, a prevailing opinion in U.S. and other jurisdictions that utilize an adversarial system was that the cross-examination was the time at which any errors or deficiencies in the experts’ conclusions would be revealed. This has been shown, in case after case of miscarriages of justice, not to be the judicial panacea of forensic truth seeking. Indeed, even in cases where lawyers feel that a Daubert challenge would be justified, they often lack the resources, both in terms of their scientific knowledge and financial means, to do so [6]. The purpose of this chapter is, first, to define the terms used when assessing efficacy of tests and, second, to demonstrate and appraise some of the research that has been conducted to satisfy the requirements of Daubert. Having outlined this purpose, it should be recognized that there is nothing in the literature to suggest that U.S. courts review bitemark evidence to the level indicated by Daubert; indeed, there are no recorded cases of the Daubert standard being used to exclude bitemark evidence within any U.S. trial [7]. This is despite a number of cases in which DNA evidence has exonerated defendants—for example, the trial of Burke v. Town of Walpole, 405 F.3d 66 (1st Cir. 2005). In Burke, exculpatory DNA evidence directly contradicted the inculpatory bitemark evidence, but the court stated that the error was due to the practitioner (a single, flawed individual) rather than the discipline as a whole [7]. Further cases on the miscarriages of justice were discussed in a former chapter, as were concerns over the application of the Daubert standard to bitemark analyses.

bitemarks are considered, one can consider two types of reliability. The first is interexaminer reliability (or agreement). This is a measÂ�ure of the examiner’s reliability. If the same individual examined the same bitemarks 100 times, would the individual arrive at the same conclusion every time [8]? The second is intraexaminer reliability, which measÂ�ures the reliability of the test in the hands of several individuals; that is, if the same case is presented to 100 odontologists, would they all arrive at the same result [9]? 34.2.2â•…Validity This is often misunderstood as accuracy. Validity is simply defined as whether the test is measÂ�urÂ�ing what it claims to measÂ�ure. This is of particular importance when indirect measÂ�ureÂ�ments are considered; for example, the detection of caries from dental radiographs is an indirect measÂ�ureÂ�ment. It has been established that an increase in radiographic translucency is a valid measÂ�ure of demineralization and hence radiographs are suitable tests for the diagnosis of caries [8]. Within bitemarks, validity is associated with the analysis technique. For example, are the biting edges of the teeth represented on transparent overlays a valid means of assessing an injury [9]? 34.2.3â•…Accuracy This is very simply defined as the percentage of correct results from any given test. Accuracy is usually presented in the following way: “Dr. Smith was 90% accurate when he assessed 100 bitemark cases” [8]. Accuracy is a somewhat crude measÂ�ureÂ�ment of a test’s performance and hence it is usual to include data on sensitivity and specificity [9]. 34.2.4â•…Sensitivity and Specificity

34.2â•…What Is Reliability? Statistical Definitions A number of terms and definitions are commonly used when describing the effectiveness of tests, but many of them are incorrect. It is therefore worthwhile briefly to define some of the terms encountered in this section. 34.2.1â•…Reliability Synonymous terms would be reproducibility or agreement. If a test is performed 100 times, will it give the same result on each occasion? The extent of the differences in the results is a measÂ�ure of reliability. When

Sensitivity and specificity are measÂ�ures of a test’s validity—that is, its ability to identify individuals correctly with and without the questioned disease or a test’s ability to identify correctly those responsible or not responsible for creating a bite injury [8]. In a diagnostic situation, there can be two outcomes: The person has the disease or the person does not have the disease (i.e., the suspect is responsible for the bite or the suspect is excluded as a possible biter). When the results of an examined test are compared to a gold standard, four results are possible: 1. True positive (TP): the test results indicate that an individual has the disease and this is confirmed by the gold standard.

Reliability of Bitemark Analysis

589 Gold Standard

Test Result

Positive

Negative

Total

Positive

True positive (TP)

False positive (FP)

TP + FP

Negative

False negative (FN)

True negative (TN)

FN + TN

Total

TP + FN

FP + TN

FN + TN + FP + TP

Figure 34.1â•‡ A 2 × 2 contingency table illustrating the outcomes of a comparison between a diagnostic test and a gold standard.

The gold standard can be an established test (e.g., radiographs for dental caries) or a confirmatory standard (e.g., histology sections for dental caries) [9,10]. FigureÂ€34.1 illustrates the application of these principles in a 2 × 2 contingency table that permits a clearer view of the system. These tables are commonly used to present the results of such comparisons. The sensitivity of a test is its ability to detect correctly the people who have the disease (i.e., the percentage of diseased people who are correctly diagnosed). A test that is 100% sensitive will identify every guilty biter; an insensitive test will lead to missed biters. A sensitive test results in very few false negative results. Diagnostic tests that have a high degree of sensitivity are used in situations where the consequences of a false negative result are serious. An example of this is the screening of donated blood for HIV [10]. Such highly sensitive tests are used for screening or ruling out disease; if the result of a highly sensitive test is negative, it allows the disease to be ruled out with confidence [11]. The specificity of a diagnostic test is the percentage of disease-free individuals who are diagnosed correctly. A test that is always negative for innocent suspects will have a specificity of 100%. A highly specific test produces few false positive results. Tests that exhibit a high degree of specificity are used in situations where the consequences of a false positive diagnosis are serious [12]. Examples include where a positive diagnosis leads to the initiation of complex and painful surgery, such as that which may cause an individual to make irreversible life

decisions (Alzheimer’s). Other examples include where a diagnosis could result in someone being stigmatized with an incorrect label (schizophrenia). Very specific tests are used for confirming the existence of a disease [12]. If a highly specific test is positive, the disease is almost certainly present, or the suspect is almost certainly the biter. With many diagnostic tests, sensitivity and specificity are inversely related: An increase in one will cause a reduction in the other. FigureÂ€34.2 shows a diagrammatic representation of a diagnostic test that has a specificity and sensitivity of 100%. The test results of the biter and nonbiter subjects show no overlap, so the threshold level for a diagnosis is between these distributions. If the test result is higher than the threshold, then the test is positive; if it is below, then the test is negative. All the biters and nonbiters have been correctly identified [13,14]. FigureÂ€34.3 demonstrates a more realistic situation in which the suspects’ bitemark analysis results overlap each other rather than forming two separate groups. It is apparent that the use of this (fictitious) test to identify biters will require the imposition of a cut-off or threshold point that will determine the sensitivity and specificity of the test [13,14]; that is, at what certainty levels will the suspect be excluded or implicated as the biter? At the cut-off point of 5, the test would be 100% sensitive (i.e., correctly identifying all the suspects who were Threshold

No. of Suspects

2. False positive (FP): the test result indicates that an individual has the disease but this is not confirmed by the gold standard, which finds that the individual is disease-free. 3. False negative (FN): the test result indicates that an individual is not suffering from the disease but the gold standard indicates that the disease is present. 4. True negative (TN): both the test result and the gold standard agree that the individual does not have the examined disease.

Non-biters

Biters

Odontological certainty

Figure 34.2â•‡ The probability distributions of the results of

a perfect diagnostic test. In this example, all of the biters have been correctly identified and the nonbiters excluded. There is no crossover of the populations of suspects.

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition Threshold (conclusion) level 4 3 2

1

No. of Suspects

5

Biters

Non-biters Test Result

Figure 34.3â•‡ A more realistic situation in which the bitemark analysis results overlap each other rather than forming two separate groups.

responsible for biting). However, this threshold choice would cause a reduction in specificity, producing a large number of false positive results (i.e., innocent individuals who would be branded as biters). This demonstrates the inverse relationship between sensitivity and specificity [15,16]. If the threshold point is moved to the right along the x-axis to cut-off point 1, the specificity would be 100%; however, the test would become highly insensitive [13,14]. This results in a large number of guilty suspects incorrectly assessed as nonbiters. From this example, it is clear that a test can only be 100% sensitive and specific when there is no overlap between biters and nonbiters or between diseased and nondiseased individuals. Within medical diagnostics, this is a rare circumstance and, when it does occur, the presence of disease is often so obvious that no diagnostic testing is required. There is no reason to believe that bitemark analyses would differ from these logical rules [17]. 34.2.5â•…Receiver Operator Characteristics Sensitivity and specificity describe the results of a procedure in a dichotomous way; a procedure result is either positive or negative [17]. This can be replicated in clinical practice [18]. For example, should a given tooth be extracted or not? Should a restoration be placed or not? Is this individual a biter or not? However, many clinical procedures are not dichotomous, such as probing of periodontal pockets or assessment of radiographs for caries, where a range of features is examined to produce a certainty regarding the presence or absence of disease. Indeed, bitemark assessments, as guided by the American Board of Forensic Odontology (ABFO), should be presented using one of a range of possible conclusions, rather than a dichotomous positive or negative. Is it possible to assess the

effectiveness of these tests without simply imposing an arbitrary threshold? A test known as receiver operator characteristics (ROC) provides such a technique [15,16]. The use of ROC analyses has increased rapidly over the past 20 years, in particular following the publication of Swets and Pickett’s landmark textbook [16]. Many of the early applications of ROC were in the field of radiology, where subjective results are recorded on a rating scale. The expansion of ROC into the evaluation of diagnostic and management procedures that yield numerical results indicates the acceptance of its use and validity [15,16]. ROC analysis is a graphical representation of the reciprocal relationship between sensitivity and specificity calculated from all possible threshold values. ROC analysis can be performed for procedures that provide either continuous data or rating-scale data [17–20]. The graphical nature of ROC is shown in FigureÂ€34.4. Each of the threshold values shown in FigureÂ€34.3 corresponds to an operating point on the ROC curve of FigureÂ€ 34.4 (values 1, 2, 3, 4, and 5). When a high threshold is used (point 1), all suspects are determined to be nonbiters, resulting in both a true-positive fraction (TPF) of zero and a false-positive fraction (FPF) of zero. This situation connotes high specificity (100%). This example relates to the operating point in the lower left-hand corner of the ROC curve. Using a very low threshold (point 5), it can be seen that the TPF and FPF are both 1, with a specificity of 0% and an operating point on the upper right-hand corner of the curve. This means that all the suspects have been determined to be biters. The other threshold values represent intermediate points of specificity and sensitivity between the two extremes described [17–20]. An ROC curve represents the relationship of sensitivity and specificity (and hence is a test used to determine these values) when odontologists are allowed to indicate a degree of uncertainty in their decision making not afforded when making dichotomous decisions [21]. The discriminative ability of any diagnostic test is defined by the distribution of diseased and nondiseased patients or biters and nonbiters. The overlap of these groups determines the shape and position of the ROC curve. A straight line from the lower-left corner to the upper-right corner (FigureÂ€34.4) describes a procedure in which the diseased and nondiseased distributions overlap completely and the TPF and FPF are equal at any threshold. This procedure has no discriminative value and is worthless (i.e., no better than a chance allocation of biter or nonbiter to each suspect). A perfect procedure has no overlap between the distributions of biters and nonbiters and would result in the straight line in FigureÂ€34.3.

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591

1

5

4

0.9

3

Sensitivity (TPF)

0.8 0.7

2

0.6

50% chance Perfect test

0.5 0.4 0.3 0.2 0.1 0

0

1

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

1

1-Specificity (FPF)

Figure 34.4â•‡ Receiver operator characteristics (ROC) curve of the data shown in Figure 34.3. Each point of the ROC

curve relates to one of the thresholds. This method allows a continuous assessment of specificity and sensitivity without imposition of thresholds.

34.2.6â•…A rea under the Curve The area under the ROC curve (AUC) is a measÂ�ure of the diagnostic accuracy of a procedure and is frequently used to permit comparisons between procedures or observers. Using statistical software, the AUC can easily be computed and tested for significant differences using z-scores (univariate). In the example illustrated in FigureÂ€ 34.4, the AUC for the procedure that yields no discriminative value (represented by the diagonal hashed line) has an area of 0.5, or 50%. It is no better than a random allocation of positive and negative results (e.g., flipping a coin). The perfect ROC line, represented in solid form, has an AUC of 1.0 or 100%. The results from diagnostic/management procedures used in real life fall within these two extremes of the range. The closer that an AUC is to 100%, or 1.0, the more accurate the procedure is. 34.2.7â•…Positive and Negative Predictive Values A number of articles have been published that describe the positive and negative predictive values of bitemark analysis techniques [22]. When such terms are used in diagnostic medicine, the calculations require a value for the prevalence of the disease within the tested population [10]. When considering bitemarks, it would be necessary to apply this in order to arrive at a meaningful value. Ordinarily, there is only one biter, but many suspects may be considered or many individuals may have had access to the victim. For example, in a case of child abuse where only four individuals had access to the

nonambulatory child, the prevalence could be calculated with ease: one in four. However, for the murder victim found by an interstate highway, the possible biters are almost limitless. In such a case, it would be impossible to calculate an accurate prevalence [10]. For this reason, it is not recommended that positive and negative predictive values be used to describe the effectiveness of bitemark assessments [12].

34.3â•…Reliability, Daubert, and the Law Courts: The New Gatekeepers of Forensic Science? Frye, Daubert, and Kumho are well-known terms for those concerned with the acceptance of expert opinion evidence in the United States. However, the spirit behind these rulings is likely to influence commonwealth and European law, and thus odontologists the world over should be interested in the admissibility guidelines that have been developed through these judgments. In 1993 the case of Daubert v. Merrell Dow PharmaÂ� ceuticals, Inc. finally clarified the position that Rule 702 of the Federal Rules of Evidence (FRE) governed the admissibility of expert testimony in federal courts. Daubert was a liability case surrounding the antinausea drug Bendectin (manufactured by Merrell Dow) that, in 1,700 actions, was claimed to cause birth defects. The manufacturer asked for summary judgment in the court, stating that a wealth of scientific evidence published in the literature, involving over 130,000 patients,

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Bitemark Evidence: A Color Atlas and Text, 2nd Edition

had found no evidence that the drug was capable of causing birth defects. The plaintiffs presented eight experts of their own who had conducted a number of in vitro and in vivo (animal) studies that they claimed proved that the drug caused the defects seen in the two minors, Jason Daubert and Eric Schuller. These experts had also reanalyzed the original research and claimed to have found errors. The evidence of these experts was not accepted under the Frye standard, in which expert testimony has to be generally accepted. It was decided that epidemiological studies were the accepted form of detecting birth defects, and therefore the additional experiments conducted by the plaintiff’s experts could not be admitted. Their reanalysis of the original epidemiological studies, while acceptable among the medical field, had not been published or reviewed by peers and therefore was not of a sufficient standard. Merrell Dow’s motion was therefore granted. The Supreme Court reviewed Daubert to resolve the “sharp divisions regarding the proper standard for admission of expert testimony” and developed guidelines for courts to exercise their function as gatekeepers of scientific evidence admissibility. A keystone of the Court’s advice was that any proffered theory or technique, such as bitemark evidence, can be and has been tested and that the science underlying such techniques has been published in the peer-reviewed literature. Further clarification stated that publication was not necessarily a prerequisite and did not guarantee reliability, but that studies that had been exposed to such inquiry supported admission because common errors would be detected. Courts admitting such evidence should also, it was advised, avail themselves of any studies indicating known error rates and the general acceptance of the technique within that particular field. A court would be justifiably skeptical of techniques that held only cursory support or credence within the scientific literature. It is important to note that the Supreme Court emphasized the importance of flexibility within the guidelines for admissibility. The use of vigorous crossexamination, jury direction, and other judicial tools can assist the trier of fact to assign appropriate weight to evidence that might not have the firmest scientific background. This relates to earlier decisions in which “evidence that is helpful to the Court” would be sufficient for admissibility. There has been much discussion within both the legal and forensic communities about the likely impact of the Daubert ruling. However, within forensic dentistry (bitemarks in particular), little attention has been paid to satisfying some of the requirements extolled

by the Supreme Court. The case of State v. Hodgson [23] is significant because it was the first appeal case to examine bitemark evidence in light of the Daubert ruling. Convicted of two counts of first-degree murder, Hodgson appealed the admissibility of the odontological evidence linking a bitemark on his arm to one of the decedents. Arguing that bitemark evidence was not generally accepted, he claimed that the science did not meet the requirements of Frye. The Court disagreed with Hodgson, stating that Daubert and FRE 702 had superseded Frye and that it was satisfied that bitemark evidence by an accepted expert was neither novel nor an emerging science and thus was admitted correctly. Following Marx [24] and Hodgson, no bitemark evidence has been refused admission due to arguments regarding Frye, FRE, or Daubert. Despite the Hodgson case, the discipline should still strive to produce research that develops error rates and that properly assesses the reliability of the techniques employed. Indeed, although there is a great deal of emphasis on the development of new and novel techniques, especially in the area of pattern association analysis, there appears to be a reluctance to test these techniques subsequently to develop the data that would produce the variables described previously (i.e., validity, reliability, and indications of specificity and sensitivity). A vigorous and robust approach to establishing a sound basis for bitemark analysis is essential. These sentiments are strongly echoed in the NAS report [5], which states that “research is warranted in order to identify the circumstances within which the methods of forensic odontology [bitemarks] can provide probative value.” However, a strong research strategy for bitemark analyses has yet to be devised, and the lack of funding for forensic science research and the small resources of academic units with an interest in this space threaten development.

34.4â•…The Research Let us look at four published studies examining the reliability of bitemark analysis, each with very different methodologies. Another study has examined the use of statistics within forensic bitemark analysis in an attempt to gauge the impact of the evidence and the extent to which it assists the trier of fact to reach a conclusion on guilt. 34.4.1â•…Whittaker, 1975 Published in both the International Dental Journal and the International Journal of Forensic Dentistry [25], this

Reliability of Bitemark Analysis A

593 B

C

Figure 34.5â•‡ A simulation of the Whittaker study. (A) A dental study model. (B) The resultant “bitemark” impressed in dental wax. (C) The “docking” and comparison of the study model with the three-dimensional bitemark.

study was the first to test the validity of bitemark analyses empirically and is frequently cited as supporting evidence for the use of the technique. In this study, two examiners were employed to examine bites recorded on wax and pigskin and also photographs. In each case, dental study models were used as comparisons and overlays were not employed, although the examiners were able to use metric analysis. The results from the study were initially encouraging. The two examiners were able to identify 98.8% of the impressions in wax correctly to the appropriate study model with a similar accuracy achieved when comparing the stone models produced from the wax bites. The comparison method was undertaken by trying to fit the study model into the wax record. When photographs were employed, the accuracy decreased slightly to 96% when measÂ�ureÂ�ments were taken, and when only a visual assessment was used, it fell again to 67.5%. When the pigskin was assessed, this resulted in accurate assessments in 63.7% of attempts; however, when photographs of the pigskin 24 hours after biting were used, this fell to 16%. The study clearly identifies difficulties with bitemark analyses. The ability to match study models to wax

bites is, as suggested by the study, a simple matter. This is a reflection of the properties of softened dental wax to register tooth impressions. Wax is an excellent material for bite registrations; indeed, it is used clinically for this very purpose (FigureÂ€34.5). However, it is very dissimilar to human skin, which is generally regarded as a poor registration media. This is endorsed by the results from the pigskin study, in which increasing time since biting resulted in a dramatic drop in accuracy. 34.4.2â•…Pretty and Sweet, 2001 The ability of odontologists to identify bitemarks on pigskin was investigated in a recent study [4]. It employed digital bitemark overlays on simulated pigskin bites. Pigskin A was a series of 10 postmortem bites created in pigskin using dental casts mounted in a vise grip. Each of the bites was photographed according to ABFO guidelines. Two suspects were associated with each case (one responsible for the bite and the other a “distractor”). However, in two of the cases, neither of the suspects supplied to the examiners was responsible for the bite (i.e., these were cases where exclusions should have been reached).

594

Bitemark Evidence: A Color Atlas and Text, 2nd Edition Conclusion Level

Sensitivity % (Sd)

Specificity % (Sd)

Youden’s Index

Reasonable medical certainty

27.5 (±24.1)

98.3 (±5.2)

0.26

Probable

57.5 (±26.5)

94.9 (±11.0)

0.52

Possible

81.3 (±22.2)

55.3 (±30.0)

0.40

Exclusion

88.8 (±19.1)

47.7 (±24.0)

0.36

0.0 (±0.0)

0.00

Inconclusive

100.0 (±0.0)

Figure 34.6â•‡ Data from the diplomates’ responses in the Pretty and Sweet study.

The examiners were provided with photographs of the bites, the suspects’ study models, and transparent overlays of each suspect. The examiners were asked to reach a conclusion regarding each suspect and report their conclusions using the ABFO conclusions for bitemark analyses. The examiners conducted their examinations twice, following a wash-out period of 3 months in order to determine values for both intra- and interÂ� examiner reliability. While a number of different groups took part in the experiment, only the results of the diplomates of the ABFO will be discussed here. The results were encouraging. The accuracy scores, when measÂ�ured using ROC analysis, were an AUC of 80.5%. Sensitivity and specificity scores, for each level of conclusion, again measÂ�ured by ROC, are shown in FigureÂ€34.6. If a forced decision model was used (i.e., the odontologists could only indicate “biter” or “nonbiter”), the accuracy was 83.2%, which is rated as substantial agreement. However, it is important to note that the range of scores was wide, from 65% to 100%, indicating that some odontologists performed significantly better than others [4]. The interexaminer scores—how much the odontologists agreed with each other—were rated as only moderate and the intraexaminer agreement as fair. This was a surprise finding because a reliable technique should demonstrate substantial agreement when employed by examiners of similar experience and training. In summary, the study found that, in the hands of certain odontologists, bitemark overlays were a reliable and accurate method of identifying biters. However the wide range of accuracy and reliability scores suggested that individual odontologists should engage in self-proficiency testing so that error rates for each expert were available for scrutiny. Indeed, in the UK, individual surgeons are required to publish their success rates for each procedure they undertake [4]. Like all studies, this work had its compromises, which must be discussed in order that the results can be placed in context. First, the bites were in pigskin, which, although a good analogue for human skin, is still

Figure 34.7â•‡ An example of the bitemarks in pigskin used

by Pretty and Sweet. Note that this would be regarded as a bitemark of extremely high forensic significance despite the fact that it has been created postmortem.

only a model. Second, the bites were created postmortem and as such none of the bruising or perimortem effects were present. An example of a bitemark from the study is shown in FigureÂ€ 34.7, demonstrating that the bites employed were on the higher end of the scale of forensic significance. An important limitation of this study is that only overlays were studied. Odontological assessment of a bite injury will usually involve a number of different techniques before a conclusion is reached. A study in which authentic forensic cases and materials were employed was conducted by the ABFO. 34.4.3â•…The ABFO Bitemark Workshop, Arheart and Pretty, 2001 The ABFO has been instrumental in the development of guidelines for bitemark analysis and for furthering the study of the discipline in order to determine the validity of bitemark comparisons [26]. Further, the ABFO

Reliability of Bitemark Analysis

A

595

B 1:1

C

D

Figure 34.8â•‡ An example from each of the four cases (A–D) presented to the ABFO diplomates in the 1999 bitemark workshop.

odontologist (in these cases) scored little better than a random allocation of biters and nonbiters, while the best performers correctly identified every biter [26]. This result is similar to that of the previous study (i.e., the mean scores reflect a test or methodology that is reliable and accurate, but that belies the range of scores 1.0 0.9 0.8 0.7 Sensitivity

conducted a bitemark workshop where 32 diplomates assessed a total of four bitemark cases and seven potential suspects. Unlike the previous study, all seven suspects were to be assessed for all four cases, rather than an association between a number of suspects and an individual case. Three of the four cases were authentic cases in which a bitemark was present on the skin of a deceased individual and had been previously investigated and litigated. The fourth case was a bitemark in cheese created specifically for the study. FigureÂ€34.8 demonstrates examples from each of the cases assessed [26]. The diplomates were provided with a 7-point scale to rate their confidence in their conclusions for each case; these were (1) reasonable medical certainty, (2) probable, (3) possible, (4) improbable, (5) incompatible, (6) inconclusive, and (7) nondiagnostic (insufficient forensic detail). In order to analyze these data, ROC was again employed; the curve that was produced is shown in FigureÂ€34.9. The mean area under the curve—the measÂ� ure of diagnostic accuracy—was 0.86. This is similar to that obtained by the previous study. The study also published, anonymously, the range of ROC AUC data for each of the 32 examiners, to demonstrate the spread of ability. This ranged from an AUC of 0.52 to 1.00. An interpretation of these results is that the poorest performing

0.6 0.5 0.4

ROC area = 0.86 95% Cl = (0.82 – 0.91)

0.3 0.2

Smoothed Actual

0.1 0.0

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1-Specificity

Figure 34.9â•‡ The ROC curve from the 1999 ABFO bitemark workshop data.

596

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

with a significant spread of abilities). One must exercise caution in the interpretation of these results. When the diplomates undertook the study, it was not as a proficiency test and therefore the amount of time or effort given to the cases may not have been equal among the examiners. Similarly, the conditions were not standardized; only a small number of cases were examined, with some diplomates stating that the forensic significance of the cases, in general, was low [26]. Another factor is that of experience. Although all the examiners were diplomates, current ABFO requirements state that only two bitemark cases must be undertaken in order to satisfy the requirements for eligibility, although, in 2012, seven cases will be required. It is therefore likely that the group still represented a wide spread of experience in the assessment of bitemarks [26]. 34.4.4â•…Dorion and Roberts, 2001 This study was described in detail in the first edition of this textbook. In summary, it involved matching bitemarks to pre- and post-treatment orthodontic dental casts [27]. Experimental bitemarks were made in Styrofoam and then an inexperienced examiner, using hollow volume overlays, compared each of these in an attempt to identify the biter. With the 50 preorthodontic bitemarks, the examiner scored 100%, positively identifying all 50 biters correctly. However, following orthodontic treatment, when the casts were more similar to each other, the score was reduced to 78%. The study demonstrated that, with highly unique features, bitemarks can be more easily identified. Care must be taken in extrapolating the high scores obtained. The bitemarks were produced in Styrofoam, which will result in simulated injuries of high definition. The skin, as described elsewhere in this textbook, is a poor registration medium of bitemarks and hence one would not expect such a high accuracy rate in studies using this as the bitten substrate [27]. 34.4.5â•…Pretty and Bowers, 2009 This recently published research examined shelf data in the form of judicial case work to establish the degree of reliability between forensic odontologists [28]. The authors readily accept the limitations of the study design—in particular, the potential bias caused by the sampling technique—but the results were concerning. The study describes the frequency of disagreement between experts and the link to the forensic significance of the bitemark injury. It argued that there was

a statistically significant difference in the “quality” of the bitemark in those cases where experts agreed versus those cases where there was disagreement. Bowers argues that in order to reduce the instances of expert disagreement and hence the chances of a miscarriage of justice, bitemark analysis should be restricted to injuries with the highest level of forensic significance. He points to cases of DNA exonerations featuring some of the lowest levels of forensic detail as support for his argument. Dorion cited as much in the first edition of this textbook. While this study is not empirical research, it represents one method by which bitemark research can go forward. There are currently two schools of approach: one in which cadaver material is used (either human or pig) to investigate the physical and mechanical characteristics of bitemarks (favored by Dorion, Bush, and Miller, among others [27,29–32]) and a second approach based upon questioning previous evidence and the views and practices of odontologists (favored by Pretty and co-workers [28,33,34]). Both approaches are valuable and will add substantially to the evidence base.

34.5â•…Statistics and Bitemarks The statistics provided previously are descriptive statistics (i.e., they help us understand the value of bitemark analysis as a diagnostic test) [4]. However, there have been several forays into bitemark evidence quantification (i.e., attempts to provide a numerical value to represent confidence within a conclusion). Some experts have attempted to provide population statistics: “There is only a 1 in 120,000 chance that an individual other than the defendant caused this bitemark.” Such statements should be avoided because there is no quantitative base for bitemark analysis (this is reviewed in greater detail in the next chapter) [4]. There has, however, been a great deal of interest in the application of Bayesian statistics to the discipline of bitemark analysis. This is a complex topic that is discussed in an excellent paper from researchers in New Zealand [36]. The basic premise is that the jury should be able to measÂ�ure the impact of bitemark evidence in a quantitative manner and thus be properly able to assess the likelihood of the accused being guilty. The authors of the study, after a thorough discussion, quite correctly conclude that bitemark analysis is an inherently qualitative discipline lacking the required population data to support a more quantitative approach. It is further argued that the application of statistics, be it Bayesian

Reliability of Bitemark Analysis

or otherwise, is fundamentally incorrect and is more likely to confuse, confound, and bemuse than to assist the trier of fact to appropriate correct weight to the bitemark evidence supplied [36]. It is an attractive proposition to attach grand mathematical statements to bitemarks. It comforts judges and juries and could be the last thing heard and retained from testimony. However, despite the appealing nature of forensic dentists, one should refrain from such statistics; instead, a concentration on the proven research should provide the basis for justification of opinions. A working knowledge of the descriptive statistical methods described within this chapter should equip a forensic dentist with the skills to present findings with appropriate and reliable data and to be able to describe and justify the research upon which they are based [36].

34.6â•…Summary The research suggests that biter identification is a potentially valid and reliable methodology. It is generally accepted within the scientific community, although the basis of this acceptance within the peer-reviewed literature is weak. Only three studies mentioned here examined the ability of odontologists to utilize bitemarks for the identification of biters (a fourth, Dorion’s latest contribution, is mentioned elsewhere in this edition), and only two studies have been performed in what could be considered a contemporary framework of attitudes and techniques [2]. Data from these studies tend to suggest that odontologists can achieve near perfect results utilizing bitemark overlays on both artificial and forensically authentic material. However, they also suggest that the range of ability is wide, which indicates that the tests are still subjective, with a poor rating of interexaminer agreement. Such results may provide the justification for individual odontologists taking part in self-proficiency tests so that their performance can be placed within the wide

597

range already described. It is also a strong argument for more formal training programs and strong mentorship of junior odontologists. Further research is required to assess the impact of case experience, teaching and learning effects, and other factors that may influence the ability of odontologists to improve their accuracy and reproducibility scores. How does the bitemark data compare to other forensic disciplines? Both footprint and fingerprint comparisons share similarities with bitemark identification in that each technique is involved, in some part, with the comparisons of patterns and the associations between them. The NAS report highlighted pattern and impression evidence as areas of forensic science for which the evidence base was weak [37]. A study was conducted comparing the examinations of 23 footwear experts on two cases [38]. There was a high degree of disagreement among the experts, with scientists within the same laboratory reaching polarized conclusions on the likely identification [38]. Similarly, a study of fingerprint experts in 1996 found wide-ranging disagreement [39]. If one considers bitemark analysis compared to other diagnostic tests in clinical dentistry (upon which decisions to initiate treatment are based), the data compare favorably (FigureÂ€34.10). This section commenced with a discussion of the Daubert ruling and its role as a driver for evidence-based research; the NAS report [37] adds additional weight to this call. Has the odontological community satisfied the principles extolled by the ruling and will it rise to the challenges articulated by the National Academy of Sciences? The answer is not clear; certainly, forensic odontologists have been shown to embrace research and have been prepared to publish results of their performance. Substantial further work is required to answer the Daubert question in its entirety. While there has been an increased level of activity within the odontological research space, particularly in the field of bitemark mechanics, a more concerted effort and enhanced funding are required, especially in the post-NAS report world.

598

Bitemark Evidence: A Color Atlas and Text, 2nd Edition Test

Sensitivity %

Specificity %

Author

Caries Clinical examination

13

94

Verdonschot et al. [39]

Fiber optics

13

99

Verdonschot et al. [39]

Radiographs

58

66

Verdonschot et al. [39]

Fissure discoloration

74

45

Verdonschot et al. [39]

Electrical resistance

96

71

Verdonschot et al. [39]

Bite-wing radiographs

73

97

Mileman et al. [40]

Probe and look

58

94

Mileman et al. [40]

Periodontics Bleeding on probing

29

88

Müller et al. [41]

PMN gelatinase

79

88

Teng et al. [42]

Bone loss

91

96

Jeffcoat [43]

Beta glucuronidasc

89

89

Lamster [44]

Temperature

83

83

Kung et al. [45]

Gingival redness

27

67

Haffaice et al. [46]

Plaque

47

65

Haffaice et al. [46]

Antibody assay

65

80

Hujoel et al. [47]

Bitemarks Overlays

71.8

81.5

Pretty and Sweet [4]

Any technique

77.2

86.0

Arheart and Pretty [26]

Figure 34.10â•‡ Comparison of effectiveness of a range of dental diagnostic tests with that of bitemark analysis.

References 1. American Board of Forensic Odontology. 1986. Guidelines for bite mark analysis. Journal of American Dental Association 112 (3): 383–386. 2. Pretty, I. A., and D. Sweet. 2001a. The scientific basis for human bitemark analyses—A critical review. Science & Justice 41 (2): 85–92. 3. Atsu, S. S., K. Gokdemir, and P. S. Kedici. 1998. Human dentinal structure as an indicator of age. Journal of Forensic Odontostomatology 16 (2): 27–29. 4. Pretty, I. A., and D. Sweet. 2001b. Digital bite mark overlays—An analysis of effectiveness. Journal of Forensic Sciences 46 (6): 1385–1391. 5. National Academy of Sciences. 2009. Strengthening forensic science in the United States: A path forward. Washington, D.C.: National Academies Press. 6. Scheck, B., P. Neufeld, and J. Dwyer. 2001. Actual innocence. New York: Signet. 7. Pretty, I. A., and D. J. Sweet. 2006. The judicial view of bitemarks within the United States criminal justice system. Journal of Forensic Odontostomatology 24 (1): 1–11.

8. Pretty, I. A., and G. Maupome. 2004. A closer look at diagnosis in clinical dental practice: Part 1. Reliability, validity, specificity and sensitivity of diagnostic procedures. Journal of Canadian Dental Association 70 (4): 251–255. 9. Brunette, D. 1998. Critical thinking. London: Quintessence Books. 10. Pretty, I. A., and G. Maupome. 2004. A closer look at diagnosis in clinical dental practice: Part 2. Using predictive values and receiver operating characteristics in assessing diagnostic accuracy. Journal of Canadian Dental Association 70 (5): 313–316. 11. Landis, J. R., and G. G. Koch. 1977. The measÂ�ureÂ�ment of observer agreement for categorical data. Biometrics 33 (1): 159–174. 12. Glaser, A. N. 1995. High-yield bio-statistics. Baltimore, MD: Williams and Wilkins. 13. Dunn, G., and B. Everitt. 1995. Clinical bio-statistics— An introduction to evidence-based medicine. London: Edward Arnold. 14. Everitt, B. S. 1989. Statistical methods for medical investigators. London: Edward Arnold.

Reliability of Bitemark Analysis 15. Hanley, J. A. 1989. Receiver operating characteristic (ROC) methodology: The state of the art. Critical Reviews in Diagnostic Imaging 29 (3): 307–335. 16. Swets, J. A., and R. M. Pickett. 1982. Evaluation of diagnostic systems: Methods from signal detection theory. New York: Academic Press. 17. van Erkel, A. R., and P. M. Pattynama. 1998. Receiver operating characteristic (ROC) analysis: Basic principles and applications in radiology. European Journal of Radiology 27 (2): 88–94. 18. Hildebolt, C. F. et al. 1991. ROC analysis of observerresponse subjective rating data—Application to periodontal radiograph assessment. American Journal of Physical Anthropology 84 (3): 351–361. 19. Swaving, M. et al. 1996. Statistical comparison of ROC curves from multiple readers. Medical Decision Making 16 (2): 143–152. 20. Hanley, J. A., and B. J. McNeil. 1982. The meaning and use of the area under a receiver operating characteristic (ROC) curve. Radiology 143 (1): 29–36. 21. Anon. 1988. Identity sought. Canada Journal 16 (9): 61. 22. Bowers, C. M., and R. J. Johansen. 2002. Bitemark evidence. In Modern scientific evidence, ed. M. J. Saks. New York: West Publishing Co. 23. State v. Hodgson, 512 N.W. 2d 95. 24. People v. Marx, 54 Cal. App.3d 100, 126 Cal. 350. 25. Whittaker, D. K. 1975. Some laboratory studies on the accuracy of bite mark comparisons. International Dental Journal 25 (3): 166–171. 26. Arheart, K. L., and I. A. Pretty. 2001. Results of the 4th ABFO bitemark workshop—1999. Forensic Science International 124 (2–3): 104–111. 27. Dorion, R. B., and J. D. Roberts. 2001. Bitemark Project 2000—Objectivity. In AAFS, Seattle, WA. 28. Bowers, C. M., and I. A. Pretty. 2009. Expert disagreement in bitemark casework. Journal of Forensic Sciences 54 (4): 915–918. 29. Dorion, R. B. 1984. Preservation and fixation of skin for ulterior scientific evaluation and courtroom presentation. Journal of Canadian Dental Association 50 (2): 129–130. 30. Bush, M. A. et al. 2009. The response of skin to applied stress: Investigation of bitemark distortion in a cadaver model. Journal of Forensic Sciences 55 (1): 71–76. 31. Miller, R. G. et al. 2009. Uniqueness of the dentition as impressed in human skin: a cadaver model. Journal of Forensic Sciences 54 (4): 909–914. 32. Bush, M. A. et al. 2009. Biomechanical factors in human dermal bitemarks in a cadaver model. Journal of Forensic Sciences 54 (1): 167–176. 33. Pretty, I. A. 2008. Forensic dentistry: 2. Bitemarks and bite injuries. Dental Update 35 (1): 48–50, 53–54, 57–58 passim.

599 34. Pretty, I. A. 2003. A Web-based survey of odontologists’ opinions concerning bitemark analyses. Journal of Forensic Sciences 48 (5): 1117–1120. 35. Kittleson, J. M. et al. 2002. Weighing evidence: Quantitative measÂ�ures of the importance of bitemark evidence. Journal of Forensic Odontostomatology 20 (2): 31–37. 36. National Academy of Sciences. 2009. Strengthening forensic science in the United States: A path forward. Washington, D.C.: National Academies Press. 37. Shor, Y., and S. Weisner. 1999. A survey on the conclusions drawn on the same footwear marks obtained in actual cases by several experts throughout the world. Journal of Forensic Sciences 44:380–384. 38. Evett, I. W., and R. L. Williams. 1996. A review of the 16 points fingerprint standard in England and Wales. Journal of Forensic Identification 46:1285–1293. 39. Verdonschot, E. H., E. M. Bronkhorst, R. C. Burgersdijk, K. G. König, M. J. Schaeken, and G. J. Truin. 1992. Performance of some diagnostic systems in examinations for small occlusal carious lesions. Caries Research 26 (1): 59–64. 40. Mileman, P., D. J. Purdell-Lewis, P. Dummer, and L. van der Weele. 1985. Diagnosis and treatment decisions when using bitewing radiographs—a comparison between two dental schools. Journal of Dentistry 13 (2): 140–151. 41. Müller, H. P., E. Streletz, R. F. Müller, and D. E. Lange. 1991. Microbiologic diagnosis and treatment of periodontally involved, “hopeless” teeth. International Journal of Periodontics and Restorative Dentistry 11 (5): 376–386. 42. Teng, Y. T., J. Sodek, and C. A. McCulloch. 1992. Gingival crevicular fluid gelatinase and its relationship to periodontal disease in human subjects. Journal of Periodontal Research 27 (5): 544–552. 43. Jeffcoat, M. K. 1992. Radiographic methods for the detection of progressive alveolar bone loss. Journal of Periodontology 63 (4 Suppl): 367–372. 44. Lamster, I. B. 2000. In-office diagnostic tests and their role in supportive periodontal treatment. Periodontology 12: 49–55. 45. Kung, R. T., B. Ochs, and J. M. Goodson. 1990. Temperature as a periodontal diagnostic. Journal of Clinical Periodontology 17 (8): 557–563. 46. Haffajee, A. D., S. S. Socransky, and J. M. Goodson. 1983. Clinical parameters as predictors of destructive periodontal disease activity. Journal of Clinical Periodontology 10 (3): 257–265. 47. Hujoel, P. P., L. H. Moulton, W. J. Loesche. 1990. Estimation of sensitivity and specificity of site-specific diagnostic tests. Journal of Periodontal Research 25 (4): 193-6. Erratum in: Journal of Periodontal Research 25 (6): 377.

Resolving Issues in Bitemark Analysis Iain A. Pretty

35

Contents 35.1 35.2 35.3 35.4

Introduction The Evidence Human Skin as a Bite Registration Material Methods of Analysis 35.4.1 Physical Comparisons 35.4.2 Molecular Biological Techniques 35.5 Bitemarks as Exculpatory Evidence, Levels of Conclusion 35.6 Uniqueness of the Human Dentition 35.7 Conclusion References

35.1â•…Introduction Within medicine and dentistry there is a movement toward an evidence-based approach to treatment, diagnosis, and management [1]. While some authors have argued that the evidence-based approach is fundamentally flawed (mainly citing the nature of the studies published within the literature and the reluctance to publish negative results), many have agreed that an evidence-informed or research-based philosophy is a sound premise [1]. Forensic science should aspire to no lesser a goal; the decisions that are made by the judicial system, informed partly by evidence resulting from scientific tests, have implications that can be at least as serious as those facing the medical profession. A number of authors have reviewed the research supporting the practice of bitemark analysis, although few of these could be considered as critical reviews [2–4]. It could be argued that there is a cyclical justification for bitemark analysis, with very few empirical studies examining the underlying science of the comparative process [5]. The reasons for this lack of an evidence base and the barriers to achieving it were reviewed in 2006 [6]; the main issues are related to the employment status of odontologists, lack of recognition of the specialty with dental schools, and the near absence of funding.

601 601 601 606 606 607 608 608 612 612

There has been a resurgence in bitemark research over the past 5 years and it is pleasing to note that much of this has been empirical research—testing of hypotheses rather than noncritical reviews and case reports, which add little to the evidence base [7,8]. The publication of all these papers has predated the National Academy of Sciences report on forensic science [9], and one might expect this trend of increased research rigor within the discipline to be further invigorated by the contents and recommendations of the report. From an assessment of the articles and the abstracts published in the odontology section of the annual meeting of the American Academy of Forensic Sciences, a number of unresolved areas within bitemark practice can be identified: • Human skin as bite registration material • Methods of analysis • The use of bitemark analysis as purely exculpatory evidence, levels of conclusion • The uniqueness of the human dentition This chapter addresses each of these issues in turn, examining the research base to determine if conclusions can be drawn.

35.2â•…The Evidence

35.3â•…Human Skin as a Bite Registration Material

FiguresÂ€35.1 and 35.2 show the distribution of bitemark literature both temporally and in terms of category of published work.

Throughout the pages of this book, it has been apparent that there is a wide variation in the appearance of bitemarks upon skin; this variation has led to its accuracy

601

602

Bitemark Evidence: A Color Atlas and Text, 2nd Edition Papers Published, by Year, Concerning Forensic Bitemarks

35 30 25 20 15 10 5

0 06

–2

01

5 20

01

–2

00

0 20

96

–2

00

5 19

91

–1

99

0 19

86

–1

99

5 19

81

–1

98

0 19

76

–1

98

5 19

19

71

–1

97

1 97 –1 66

19

19

60

–1

96

5

0

Figure 35.1â•‡ Number of papers concerning forensic bitemarks published in English between 1960 and 2010. Papers sourced from MedLine, ISI Web of Science, and Forensic Abstracts.

Distribution of Bitemark Literature

35

% of Papers

30 25 20 15 10 5 0

Case Report

Commentary

Empirical

Review

Technique

Legal

Figure 35.2â•‡ Categorical assessment of bitemark publication type from 1960 to 2010.

as a bite registration (or recording) material being questioned. It is important to point out that bitemarks can occur on a number of other substrates, such as cheese [10–12], apples [11,13], sandwiches [14], and soap [15], but it is the issues surrounding human skin that have been examined most within the literature. Skin is a poor registration medium [16] since it is highly variable in terms of anatomical location, underlying musculature or fat, curvature, and looseness or adherence to underlying tissues [17]. Skin is highly viscoelastic, which allows stretching to occur during either the biting process or when evidence is collected. This is due to elastic fibers in the dermis distorting under pressure and then recoiling to the original position. The degree to which this occurs depends on a number of

factors, including the age of the bitemark recipient and the anatomical location of the bitemark [18]. It has been argued that any bitemark on skin will have some degree of distortion, due to edema, recoil, or other factors. This was well demonstrated in a study conducted in 1971 by DeVore [19]. The experiment involved the inking of human skin (living volunteers, typically on the arm) using a stamp with two concentrically placed circles with intersecting lines. Photographs of the inked skin were taken before and after movement and the distortion was measÂ�ured. Following the analysis of the photographs, it was found that in all cases there was an expansion or shrinkage of the inked mark, with a maximum linear expansion of 60% at one location [19]. The design of the stamp

Resolving Issues in Bitemark Analysis

A

603

B

C

D

Figure 35.3â•‡ The DeVore experiment revisited; (A), (B), (C): an inked area of the dorsal midforearm demonstrating the dimensional (postural) changes achieved by arm flexion; (D): the original ink stamp.

permitted the investigators to examine the distortion in both size and direction. DeVore concluded that, due to the level of distortion found, photographic images of a bitemark in comparative analysis should be used only if the exact position of the body can be replicated [19]. Clearly, this is an almost impossible task. If one considers that most bitemarks are examined in a morgue environment, then the body has most certainly been moved. Even if the bitemark is examined at the crime scene, the position of the body at the time of biting is usually unknown. An exception to this is in the case of a living victim, who, if conscious at the time of biting, may be able to recall the position (FigureÂ€35.3). Clearly, some anatomical positions are less prone to distortion than others. Typically, areas that have small amounts of subcutaneous fat and areas that are not distorted by movement are less prone to the effects that DeVore describes [4,5]. Such areas include the dorsum of the hand and foot, the middle regions of the arm, and the scalp. However, if one examines the anatomical positions where bitemarks are most frequently found, it is more likely than not that a bitemark will be located in an unfavorable position in relation to skin distortion [20,21] (FigureÂ€ 35.4). When assessing DeVore’s work it is important to note that the skin was simply impressed with an inked stamp; no force was used. It could be extrapolated that, with the additional force component

necessary to create a bitemark, the distortion effect could be even greater. In 1974, researchers from the Bioengineering Unit of the University of Strathclyde examined the features of the biting process likely to impact the appearance of bitemarks on human skin [16]. The study describes the differing characteristics of skin from a variety of anatomical locations; for example, Langer’s lines represent directional differences in the degree of extensibility of skin. Like DeVore, the importance of body location was emphasized during biting as the directional variations or tension lines alter with movement. Also described was the distortion that can occur in skin after biting [16]. The edematous response of skin to trauma is likely to stiffen the area, thus rendering it more stable. However, the subsequent resorption of this fluid will cause a large amount of distortion. The conclusion derived was that the changes in bitemark appearance are likely to be greater as the injury grows older. This was found equally applicable to both living and dead victims. The article concluded that forensic odontologists where “still ignorant … of the conditions during normal biting … [and] considerable research is required” [16,22]. Provisional results from the Strathclyde study and others were described in one of the major forensic dental texts, Dental Identification and Forensic Odontology [23]. Chapter 13 of Harvey’s book concentrates on a number

604

Bitemark Evidence: A Color Atlas and Text, 2nd Edition Vale and Noguchi Anatomical Location

Harvey

Pretty and Sweet

Number of Bitemarks

Percent of 164 Marks

Number of Bitemarks

Percent of 71 Marks

Abdomen

12

7.3

10

14.1

3

2.1

Arms

32

19.5

5

7.0

27

18.8

Back

20

12.2

0

0.0

10

6.9

Breasts

17

10.4

23

32.4

45

31.3

Buttocks

8

4.9

3

4.2

3

2.1

Chest

7

4.3

0

0.0

4

2.7

Ears

1

0.6

1

1.4

1

0.7

13

7.9

12

16.9

7

4.9

Feet

2

1.2

0

0.0

0

0.0

Genitalia

9

5.5

3

4.2

11

7.6

Hand/finger

4

2.4

5

7.0

8

5.5

Legs

23

14.0

1

1.4

19

13.1

Neck

5

3.0

1

1.4

1

0.7

Nose

3

1.8

1

1.4

1

0.7

Shoulder

8

4.9

6

8.4

4

2.7

Face/head

Total

164

71

Number of Bitemarks

Percent of 144 Marks

144

Figure 35.4 Data from three studies examining the anatomical location of bitemarks. The anatomical positions most frequently bitten are often those sites most susceptible to postural distortion.

of studies in which experimental bites were produced on a living volunteer. As well as photographic studies, histological samples obtained via biopsies were undertaken. A total of five bites were produced on a variety of anatomical positions, and biopsies were taken immediately and on 5 consecutive days. Photographs were taken immediately and then each day for 5 days. When examining the photographic data, Harvey found considerable change in bitemark appearance after 24 hours; this continued, at a slower rate, for the remaining 5 days. He noted that, although the biter had attempted to use similar force at each anatomical location, each bite appeared to be quite different. Bites on the thorax and shoulder displayed clear teeth marks but little bruising or hemorrhage, while those on the abdomen appeared more severe. These results demonstrate the effect of anatomical variation on bitemark appearance and its likely impact on forensic significance [23]. The histological study demonstrated that the stress applied to the skin during biting is sufficient to produce a histochemical change in the collagen fibers and that this change may be of value in assessing and describing bitemarks. The influence of collagen in the presentation of bitemarks also supports the data on the varied

appearance of bitemarks in differing anatomical locations [23]. Sheasby and MacDonald divided distortion in bitemarks into two separate areas [18]. Primary distortion is that caused at the time of biting; its two main components are that of the dynamics of the biting process and detailed features of the bitten surface. The study describes these as dynamic distortion and tissue distortion, respectively. The two processes are intrinsically linked and typically occur simultaneously. The degree of dynamic distortion can vary dramatically, from almost nil in a static bitemark to a very considerable amount in bites that demonstrate scrape marks. Sheasby comments that the dynamic distortive process is a unique occurrence depending on movements of both victim and suspect, and as such it is possible that the same biter may leave marks of differing appearance on the same victim [18]. Secondary distortion is described as comprising three elements: time, posture, and photographic. Time distortion is described as those changes that occur in the appearance of the injury from the time it occurred until it is examined. These changes could be due to contraction—for example, healing artifacts in a case of

Resolving Issues in Bitemark Analysis

605

Figure 35.5â•‡ An example of bite wound contraction. Here, the victim was bitten on his lower lip, with class characteristics of lower anterior teeth clearly visible. However, the bite wound is only 15 mm across, demonstrating significant contraction. A large fibrous area has developed in the center. Odontological evidence combined with the statement of a plastic surgeon secured a confession of biting from the suspect. The plastic surgeon stated that contraction of 30–50% could have occurred. A

B

Figure 35.6â•‡ An example of postural and photographic distortion in bite photography; (a): the original injury photograph. Postural effects from both the manual manipulation of the breast and the placement of the (inappropriate) scale have produced a significant distortion that led one odontologist to believe that this wound was a bitemark. When it was examined in the mortuary and correctly photographed, it was clear that this was not a bitemark and that the marks were postmortem changes associated with skin striae.

a laceration or abrasion that can significantly alter the dimensions and appearance of a bite injury. Indeed, it is possible for injuries to contract up to 50% in the absence of treatment (FigureÂ€35.5). Similarly, in the case of a bruise, healing can cause diffusion and possible movement of the bruise [18]. Posture distortion is described in DeVore’s study— namely, that the position of the body when bitten may be different from that when the evidence is recorded (FigureÂ€ 35.6). Photographic distortion has been aptly described in this textbook. Briefly, if the bitemark is not recorded at 90°, then photographic distortion can occur. The use of the ABFO no. 2 scale and numerous angled shots should (a) prevent photographic distortion from occurring, and (b) enable detection and corrections when it does occur [24]. Two recent studies published by Bush et al. further add to the understanding of distortion [25,26]. In

the first paper, a single dentition was applied 23 times to cadaver skin. Metric measÂ�ureÂ�ments, such as overall intercanine difference, the mesial-distal difference, and angulation, were recorded. Bites that were placed perpendicular to skin tension lines on tightly adhered skin showed the least amount of distortion, while those on loose skin parallel to tension lines demonstrated the most distortion. Movement of the body was considered with mixed results: Some movements (generally extension) led to significant distortion while other movements caused little change in appearance. When considering their data as a whole, the most concerning finding was that all 23 bites appeared different from each other, with the combinations of tension line placement and movement creating maximum differences of from –27% to +24% for intercanine measÂ�ureÂ�ments, –29% to +5% for mesial-distal measÂ�ureÂ� ments, and a range of 161% difference for angulation.

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The conclusion was that, while accepting the limitations of the cadaver model, the data suggest that distortion in bitemarks is significant and a thorough understanding of skin biomechanics and movement is essential if one is to contemplate pattern analysis or metric comparisons [26]. In the second publication [25], four sets of dental models were employed and anterior teeth were systematically removed to vary the contact surface area. Using bites made perpendicular to Langer lines to six cadavers, a range of pressures was applied. It was found that teeth impressed on loose tissue resulted in an increase in metric measÂ�ureÂ�ments and those made on tight tissues demonstrated the reverse effect. As teeth were removed from the model, a mixture of the effects was observed, thus making prediction complex. Within the qualÂ�itative assessment of the results, it was demonstrated that three bites, caused with a variety of different pressures but using the same dentition, all appeared different yet with the same degree of tissue damage (see FigureÂ€20.5 in Chapter 20). In another example, the force was kept the same; again, the bites appeared different from each other (see FigureÂ€20.5). It can be stated that skin distortion following biting is inevitable. The descriptions of Sheasby and MacDonald help to identify the type of distortion present [18]. There is little that can be done to correct or prevent primary distortion, and therefore it is essential that steps be taken to minimize secondary distortion. In either event, the forensic odontologist must be aware of the nature of both and their likely impact on the injury. Metric analysis, in which intercanine distances are measÂ�ured to a millimeter or less, is perhaps flawed because the distortion that has occurred can never be quantified in such resolution. A thorough assessment of the appearance of the injury, taking into account its anatomical position, is essential [27]. The research is unclear as to the significance of distortion. DeVore stated that unless the body position of a victim could be precisely replicated, no attempt at bitemark analysis should be undertaken. Bernstein has stated that distortion occurring in the recording and analysis of bitemarks, while serious, should not preclude analysis [22,28]. It is unlikely that further research will assist us in the handling of primary distortion; the variability of biter and victim is so great that any attempt to quantify these changes would be flawed [22,28]. The contributions made by Bush et al. help us to understand that distortion occurs on both loose and tight tissue, but is more apparent on loose tissue, and that movement and the degree of force all have roles to play. The data also suggest that the prediction of the degree or

direction of distortion (i.e., larger or smaller) is extremely complex and that the most important recommendation is to recognize that distortion occurs and modify an analysis appropriately. In some cases, this could be to abandon a pattern or metric analysis [25,26]. Despite the recent research efforts in this area, much of the data merely reveal the complexity of the issue and further research will be required. Bush et al. have assessed the factors that contribute to distortion and demonstrated the effects of such distortion elegantly; however, the impact of this on pattern and metric analyses is unclear [25,26]. It can certainly be stated that, within a bitemark, analysis attention should be directed to the chances of distortion and the likely impact of this.

35.4â•…Methods of Analysis 35.4.1â•…Physical Comparisons An essential component of the determination of the validity of bitemark analysis is that the techniques used in the physical comparison between suspect dentition and physical injury have been assessed and found valid. One of the fundamental problems with this task is the wide variety of techniques that have been described in the literature [29]. Techniques using confocal microscopy [30], reflex and scanning electron microscopes [11,31,32], complex computer systems [33,34], typing of oral bacteria, special light sources [35,36], fingerprint dusting powder [37], and overlays have all been reported [29,38–43]. Despite this, the use of transparent overlays to perform a pattern comparison is the emerging dominant technique, although the lack of direction from the forensic dental organizations, both European and North American, complicates this matter [44]. The American Board of Forensic Odontology (ABFO) has reported advice and guidance on many aspects of bitemarks and yet one of the most pivotal questions—that is, is the best comparison technique to use— has not been addressed [27]. If a court wished to review the literature to ensure that a testifying expert is using generally accepted techniques, it would find the task daunting and ultimately unrevealing. Yet, Daubert and other rulings suggest that this should be the case—that empirical evidence should exist supporting the use of techniques employed [5]. An example of research undertaken in this area is that of Sweet and Bowers [39]. This paper compared five common techniques of producing transparent overlays: radiographic, Xerox, hand drawn (directly from casts or from wax bites), and computer generated. The study employed 30 randomly selected study casts to examine the

Resolving Issues in Bitemark Analysis

accuracy of overlays produced from each of the five techniques concerning tooth rotation and surface area. The computer-generated overlays were the gold standard. From the results, it was determined that the computer technique represented the most accurate fabrication method with respect to representation of rotation and area of the biting edge [39]. In favor of techniques that are more objective, the authors of the paper concluded that the fabrication methods that utilize the subjective process of hand tracing should not be used. Despite this sound research, a review of the proceedings of the American Academy of Forensic Sciences since 1998 suggests that a number of techniques are still used [5]. The issue is further complicated in that there are a number of techniques for the fabrication of overlays using computers. There is somewhat of a European/ North American divide in the overlay fabrication system used. For example, many U.S. odontologists will employ the Sweet technique [40], while a modification of the Naru system is popular in the UK (FigureÂ€35.7) [43]. One of the highlighted difficulties with the computer-assisted systems is that the subjectivity of the process is still relatively high. Within the Sweet technique, a threshold value must be set prior to the selection of the biting surfaces of the scanned dental cast. This threshold value can affect the appearance of the overlay, and the skill of the odontologists and their subjective judgment are required to ensure that the biting surfaces are selected accurately (FigureÂ€ 35.8). The effect of tooth wear, resulting in teeth lying below the occlusal plane, is difficult to reflect in the overlay [29]. There is further discussion on this topic in Chapters 20 and 25.

607

An attempt has been made to analyze bitemarks entirely within a computer system; the cast and photograph are simply scanned into the software and the remainder of the analysis is automated without input from the odontologist [45]. The use of representative correlation coefficients was proposed to identify the most likely biter. Despite the promising nature of the project, when it was applied to a real bitemark case, the incorrect biter (based upon a court decision) was implicated by the system. In his discussion of these results, Naru stated that the skin may simply not record the dentition accurately enough to enable analysis. The pathological record of the bite on skin is subject to many variables, such as the distortion and color changes described previously that confound computer systems [45]. Naru recommended that further work be required to modify the algorithms to contend with these variations. Since this work, there have been no further attempts to employ computer systems to analyze bitemarks objectively [45]. 35.4.2â•…Molecular Biological Techniques Fully described in Chapter 10 of this book and included here for completeness, the use of salivary DNA to analyze bitemarks was proposed by Sweet [46,47]. Indeed, this is a highly objective system and offers a solution to the difficulties surrounding physical comparisons. However, the techniques are expensive and are subject to a number of variables, including the presence of sufficient DNA and the time since biting.

Figure 35.7â•‡ Examples of overlay production techniques; (a): a mandibular cast from a bitemark suspect; (b): an overlay produced using the Sweet technique; (c): using the Naru technique; (d) using a new contour technique.

a

b

d

c

e

Figure 35.8â•‡ Example of the effect of thresholding on overlay appearance; (a): a mandibular cast from a bitemark suspect; (b), (c), (d), (e): overlays produced using the Sweet technique with decreasing threshold levels set within the image analysis software.

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A number of environmental assaults can impact the quality of such evidence and its collection has been, so far, relatively poor [5]. Nonetheless, DNA evidence from bitemarks may present the most judicially acceptable methodology of bitemark analysis, particularly because there is a wealth of supporting peer-reviewed materials concerning DNA techniques. Such empirical support is either lacking or less than fully endorses the physical comparative techniques [5].

35.5â•…Bitemarks as Exculpatory Evidence, Levels of Conclusion In order to address some of the inherent complications concerning bitemark physical comparisons, a number of authors have suggested that bitemark evidence should only be employed in the exclusion of a suspect [5]. The theory behind this proposal is sound. If a bitemark is observed in which, for example, six anterior maxillary teeth are clearly observed, yet the suspect possesses only three anterior maxillary teeth (and wears no dental prosthesis), it is a simple matter to exclude the suspect as the biter. Complications of skin distortion, photographic artifacts, skin registration, occlusal wear, and bite force are irrelevant; there are simply insufficient teeth to produce such a mark. There are a number of instances in which the exclusion of biters can be of assistance in implicating an individual [48]. A classic example of this is the child abuse case in which a nonambulatory child has exposure to a closed population of individuals (e.g., mother, father, sibling, and babysitter). If it is possible to exclude three of these individuals, then, if the assumption that this is a closed population is correct, the fourth must be responsible for the bite injury. Another example is provided in FigureÂ€35.9. An argument therefore exists that the use of such evidence, in the absence of salivary DNA, should be restricted to the exclusion of suspects. The difficulty with the application of this seemingly commonsense approach is the nature of bitemark case presentation. In an audit of bitemark cases, it was found that only 18% presented with more than one bitemark suspect; in 73% of cases, the bitemark was the only physical evidence available and 84% of the crimes were rated as serious assaults or higher [49]. In none of the cases assessed was DNA available or permission given to obtain suspect samples [49]. It is likely that this audit is typical of a forensic odontological casework. The investigative services look to odontologists for assistance when more traditional techniques have failed. It is clearly a desirable situation

A

B This side towards photograph

Mx L

R Mn

Figure 35.9â•‡ An example of the value of suspect exclusion in bitemark cases. In this case, a bank was robbed. During the robbery, one of the suspects held a bank deposit book between his teeth. (A): The arrows indicate the area of the bite, demonstrating an individual with at least six anterior teeth, either upper or lower; (B): an overlay from one of the suspects. It is a simple matter to exclude this individual as a possible biter in this case because he simply has insufficient teeth to produce the mark shown in (A).

to have bitemark evidence supplied as just one aspect of a multifaceted case against a suspect in which a number of forensic tests, eyewitnesses, and a clear motive are presented to the court [21]. However, this is rarely the case, and often bitemarks are the only forensic evidence available to the jury. Because of this, there is a perceived reluctance among the odontological community to restrict bitemark evidence to exclusions only. Indeed, a recent survey of 72 U.S. odontologists, 38% of whom were ABFO diplomates, asked if bitemarks should be used only to exclude suspects; 22% of the total respondents stated yes, although only 6% of diplomates expressed this view [49]. It seems that the use of bitemarks to identify biters positively will continue; however, it is important to realize that the empirical evidence to support this is thin—never more so than when the uniqueness of the human dentition is considered.

35.6â•…Uniqueness of the Human Dentition Bitemark analysis is based on two postulates: (a) the dental characteristics of anterior teeth involved in biting are unique among individuals, and (b) this asserted uniqueness is transferred and recorded in the injury [3]. A distinction must be drawn from the ability of a forensic dentist to identify an individual from his or her dentition by using radiographs and dental records and the science of bitemark analysis. Dental identification, as opposed to bitemark identification, utilizes the number, shape, type, and placement of dental restorations, root

Resolving Issues in Bitemark Analysis

canal therapies, unusual pathoses, root morphology, trabecular bone pattern, and sinus morphology [50]. The debate over the uniqueness of human teeth is probably one of the fiercest in current forensic dental discourse and perhaps the most significant [44]. Many forensic dentists, appellants, and lawyers have questioned this fact and demand to know from testifying experts the relative frequency of dental features identified in bitemarks. An examination of the literature divulges the scientific evidence for this commonly held belief [51]. The first article to consider the statistical nature of dental uniqueness was published by MacFarlane, MacDonald, and Sutherland in 1974 [52]. The authors began by differentiating between “positive” and “negative” features of the dentition. A positive feature was described as the presence of a tooth with a certain rotation or other individualizing feature. A negative feature was the absence of a tooth. This study concentrated on the positive features that occurred on the anterior teeth (canine to canine, maxillary and mandibular). Patients were selected from an outpatient clinic and in total 200 study casts (maxillary and mandibular) were produced. The authors studied the dental casts, not bitemarks that would have been produced by such casts. This is a crucial aspect of most of the research that has been conducted on this topic (i.e., the uniqueness of the dentition rather than any pattern or wound that such teeth would produce) [52]. The investigators noted the number and shape of each tooth, the presence of any incisal restoration, relationship of teeth to arch form, and tooth rotation (four categories). The study did not examine the presence or absence of spacing between teeth. The assessments of each cast were entirely subjective. Disappointingly, the authors elected not to publish a table of results. Rather, they presented images of typical casts and calculated, using their data, the frequency of the traits shown. The authors noted that certain characteristics were not interrelated and thus the products of their incidences could be used to indicate an overall frequency. However, certain features, such as mesiopalatal rotation of the upper central incisors, were inter-related with a significance of p < .001. The authors stated that mesiopalatal rotation of the maxillary central incisors should therefore be taken as a single feature. This demonstrated that the true frequency of such features was almost four times greater than the frequency when the rotations were considered as individual variables [52]. In an example, MacFarlane concluded that a particular dentition would only be seen in eight people in 100,000 of the population with natural teeth. This figure was introduced in a U.S. trial, to much debate [53].

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The authors concluded that they had not confirmed the individuality of the human anterior teeth and they had not considered the impact or representation of any of the features examined on a bitemark in human skin. The highly subjective examination of the casts by multiple examiners and lack of tabulated results make this study weak, especially in light of the increased scientific scrutiny required by recent court rulings. However, a large (200) sample was used of a defined population and efforts were made to ensure that this sampling was randomized [52]. The next paper to address the issue of individuality of human teeth was published in 1982. Authors frequently cite it as conclusive evidence for dental individuality [54]. The premise of the paper was to examine the dentitions of five pairs of monozygotic (identical) twins and, should individualization among the pairs be established, to extrapolate this finding to the general population. The twins were selected from another, unrelated study; the authors state that no selection based on dentition was performed. None of the subjects had crowns or removable prostheses. All teeth were determined to be healthy and representative of young adults in their early 20s. Each twin underwent a complete oral examination including alginate impressions [54]. The impressions were immediately cast in plaster, and subsequently epoxy-resin replicas of the anterior teeth were made and used to create test bites in a variety of materials, including plaster of Paris and silicone impression materials. The test bites were then treated by the wax radiographic technique for overlay production and the resultant radiographs were computer analyzed. A large number of measurements were carried out by the investigators, who carefully noted asymmetries in each of the anterior teeth, angulations of test bites, and the depth of the test bites [54]. Although the article stated that efforts were made to standardize the production of these test bites, there was no discussion of how this was obtained. One crucial aspect would have been the amount of pressure applied to the epoxy replicas when creating the test bite. Many of the individual features claimed by the authors were dependent on the depth of penetration of the test bite into the substrate, and therefore a standardization of this pressure would have been necessary. The substrate, plaster of Paris, has very dissimilar properties to those of human skin [54]. It should be noted that many of the differences between the bitemarks described by the authors could be explained by the depth of substrate penetration (and hence increased width of tooth outline) by the replicas. The authors noted that the teeth did not meet at the same horizontal plane at the incisal edges in each twin. This is

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Figure 35.10 The effect of pressure on the overlay production process. This figure demonstrates the overlays produced from the same dental cast that has been impressed in dental wax using increasing amounts of pressure.

described as an individualizing difference between the twins rather than as an artifact of experimental variation. Figure 35.10 shows the difference in test bite outline produced from the same dentition applied to wax at a variety of different pressures [54]. Even if it was to be accepted that the variation caused by inconsistent pressure application is negligible, the selection of substrate is questionable. Are investigators interested in the representation of uniqueness in plaster of Paris or human skin? Should a study that determined morphological human dental uniqueness in wax or plaster be extrapolated to fulfill a legally sound statement that a bitemark on skin is unique? With the current interest in the proper application of the scientific method, this would be unlikely to meet the legal burden. Sognnaes et al. concluded that, in terms of dental arch form and individual tooth position, even identical twins are not dentally identical [54]. As previously mentioned, the effect of different wear-and-tear rates, exposure to environmental factors, dental treatments, and disease experience among such individuals will obviously cause differences over time. The twin study, despite the described problems, is one of two papers frequently cited as resounding evidence for the uniqueness of the human dentition. The other is Rawson’s 1984 article, “Statistical Evidence for the Individuality of the Human Dentition” [55]. Rawson, a coauthor on the twin study, in coauthorship with another dentist, two dental students, and a statistician, wrote the arguably most cited and wellknown bitemark paper describing an empirical experiment. In an attempt to prove, finally, the uniqueness of the anterior segment of human teeth, Rawson examined 397 bites and applied a statistical probability theory to the results. The significance of this paper warrants the comprehensive assessment of its validity that follows.

Forensic odontologists in various geographic locations in the United States submitted 1,200 wax bites. Each bite was made on a custom wax wafer 1-mm thick supported by a 1-mm hard cardboard backer. The subjects were instructed to bite to the maximum depth of 1 mm. This design removed the variation of incisal penetration found in the twin study. A calibrated 1-cm scale was also impressed upon the wax. From the 1,200 samples received, 384 bites were selected, although this was later increased to 397. There is no indication that this was a randomized sample. In order to adhere to strict scientific methods, the bites should have been selected in a random fashion to prevent any selector or observer bias being introduced. Rawson stated that the screening process involved an assessment of the clarity and accuracy of the marks as well as the completeness of an accompanying questionnaire. Another aspect of the study that is unclear is at what point the sampling was performed. Was it before or after the radiographic treatment of the bites? The bitemark indentations were filled with zinc powder and then radiographed using a technique designed to minimize any enlargement. Following the exposure of one side of the wax, the zinc was removed and the procedure repeated for the other side. A study described earlier determined that the radiographic process for overlay production was relatively accurate, but it found that hand-traced overlays were less accurate and generally unsuitable for use [39]. Rawson’s study used a combination of both techniques, thus increasing the chance of errors considerably. In this study, the radiographic overlays were enlarged three times and then traced by hand onto gridded computer paper. The article stated that the resolution of bitemark examinations should be within ±1 mm of the center point of a tooth and ±5° of rotation. Results of the study of Sweet and Bowers suggested that this resolution might be difficult to obtain using the hand-tracing method [39]. Following the selection of the bites, the population sample was described. A comparison of these figures to U.S. census data found that the population sampled in the study was a reasonable measure of the U.S. population, although African Americans were underrepresented and Asians slightly overrepresented. Following the tracing of the biting edges, several elements of tooth position were assessed. A center point for each tooth was determined and the x and y coordinates noted. The angulation of each of the teeth was measured and all the data were entered into a computer for analysis. It was determined that the minimum number of positions that a tooth can occupy is 150 and the greatest

Resolving Issues in Bitemark Analysis

239.9. These figures were determined by multiplying the number of positions of x by y and by the angles observed. The occurrence of fractions of positions (i.e., 239.9) is a reflection of this multiplication. Rawson elected to use 150 as the number of possible positions for each tooth because this represented a conservative sample. Using this premise, the article then stated that the probability of finding two sets of dentition with all six teeth in the same position was 1.4 × 1013. With an assumed world population of 4 billion (4 × 109), Rawson stated that a match at five teeth on a bitemark would be sufficient evidence to identify an individual positively as the biter to the exclusion of all others [55]. One concern with this use of the product rule to multiply individual probabilities to establish an overall likelihood is that of independence of the variables [1]. The article assumed that the position of each of the teeth was entirely independent of the position of any others. However, neither this nor any other study has established the independence of these features. Indeed, the studies described previously have shown this to be incorrect (e.g., the dependence of mesiopalatal rotation described by MacFarlane [52]). It is likely that every tooth position influences another—intraquadrant, intra-arch, and between opposing arches. This lack of independence renders Rawson’s certainties of individualization invalid. Rawson’s results also showed a possible sampling error, as evidenced by the data sets regarding possible tooth position for each unit. Intuitively, it should be anticipated that the left and right quadrants should represent a mirror image of each other in terms of possible tooth center positions. This was not the case. The upper right lateral incisor was reported to have 239.9 possible locations, while the upper left lateral incisor had 161.5 locations [55]. It can be argued that this paper, without the statistical treatment, confirms the anecdotal evidence of almost any practicing dentist that the human dentition is unique. It can be stated that, with an extremely high resolution of measurement, such as in this article, the minutia of the dentition can be described and proven unique. Indeed, if one were to measure 100-m length rules, one would find that each would be individual with regard to its length, if measured with sufficient resolution. It is therefore not the uniqueness of the teeth that is questioned; rather, it is the rendition of these asserted unique features on human skin that is the unknown quantity. Rawson alluded to this point within his article: “whether there is a representation of that uniqueness in the mark found on the skin or other inanimate objects” [55]. Rawson proved what his article claimed, although perhaps not to the mathematical or statistical certainty

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expressed. The article determined that the dentition is unique; however, when this paper is cited, authors often extend this conclusion to incorporate the uniqueness of bitemarks. The survey of odontologists described previously asked a number of questions of the respondents in relation to the question of dental uniqueness. Of the forensic dentists questioned, 91% believed that the human dentition was unique, with only 1% stating that it was not; 8% were unsure. Among the respondents, 78% believed that this uniqueness was replicated on human skin during the biting process, while 11% believed that it was not and 11% were unsure [49]. Of ABFO diplomates in this survey, 96% stated that the human dentition was both unique and accurately registered on human skin during the biting process. When questioned about the product rule and its application in the determination of dental uniqueness, 60% of the respondents did not know what the product rule was, 22% thought that its use was justified, 9% believed that it should not be used, and 9% were unsure [57]. A paper presented in 2009 at the American Academy of Forensic Sciences conference in Washington, D.C., and soon to be published in the Journal of Forensic Sciences [58], provides an interesting take on Rawson’s earlier work. Indeed, Bush, Bush, and Sheets took an alternative approach to the issue by seeking to determine the similarity of the human dentition. From a database of 344 dental models, a total of 16 matches were discovered; from a smaller set of 172, a total of 7 matches were discovered using the anterior teeth. The conclusion is written strongly: “[G]iven experimental measure ment parameters, statements of dental uniqueness with respect to bitemark analysis in an open population are unsupportable, and … use of the product rule is inappropriate” [58]. This paper was written just after the publication of the NAS report and evidences it within the manuscript, stating that the data found support the concerns of the NAS authors. The paper describes that, while the number of possible states for a tooth to exist within is vast, in reality teeth occupy relatively few of them and therefore the probability of a match is far more likely than the total number of states would suggest. While it was not a scientifically designed study, it is worth mentioning the case report of Keyes from 1925 [59]. The case report concerned a bitemark in a case of homicide (of a police officer) in which marks from the lower teeth of the suspect could be clearly seen. No maxillary teeth marks were present on the injury, and the explanation for this was that the officer was wearing a rubber coat, which may have prevented these teeth from contacting the skin.

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Keyes describes his attempts to quantify the uniqueness of the bitemark by examining over 2,000 “mouths,” none of which, he claimed, “fitted” the bitemark as well as the suspect’s. Keyes describes the fact that because the excised skin had changed following removal, it was impossible to “match” the defendant’s teeth to the mark, but that the alignment was correct [59]. In none of the 2,000 mouths was a similar alignment seen. While this evidence was, quite correctly, not accepted in court, it represents the first anecdotal evidence of dental uniqueness. It could be argued that we are still relying upon similarly anecdotal evidence nearly 80 years later [59]. The Bush et al. study calls into question the uniqueness of the human dentition and, in a study where the resolution of measurement was high, one can only consider the impact of the decrease in resolution caused when a bite is inflicted on skin. But perhaps the odontological community has spoken: The final question in a recent survey asked, “Should an appropriately trained individual positively identify a suspect from a bitemark on skin?” and 70% of the respondents stated yes [49]. It should be noted that this study was undertaken before the Bush et al. paper and it will be interesting to see, when that paper is published, the impact that this piece of work has on the odontological community. However, it is the judicial system that must assess validity, reliability, and a sound scientific base for expert forensic testimony. A great deal of further research is required if odontology hopes to continue to be a generally accepted science and meet the requirements of science as articulated in the NAS report [9,60].

35.7 Conclusion It is healthy that, within any discipline, some contentious issues exist; indeed, without an inquisitorial approach and a rejection of current theories or practice, no science would advance. In this regard, forensic dentistry is no different and, within the specialty, it is bitemark analysis that attracts the most discussion. The ABFO should be commended in its attempts to standardize protocol and promote best practice. However, if we truly want an evidence-based, scientific discipline, then the research must be available and, when it is, it should be assessed, evaluated, and, if it is determined to be of quality, the recommendations should be implemented. The advent of the NAS report provides a framework within which a research strategy could be developed to address each of the concerns systematically and to

provide evidence that either supports continued use of bitemark evidence in court or not [9]. However, there must be a recognition among odontologists that the research may suggest that the pattern analysis of bitemarks to positively identify an individual may not be supportable within a judicial burden of proof “beyond reasonable doubt” in every circumstance.

References 1. Fleiss, J. L. 1986. The design and analysis of clinical experiments. New York: John Wiley & Sons. 2. Ligthelm, A. J., and P. J. van Niekerk. 1994. Comparative review of bitemark cases from Pretoria, South Africa. Journal of Forensic Odontostomatology 12 (2): 23–29. 3. Hale, A. 1978. The admissibility of bitemark evidence. Southern Californian Law Review 51 (3): 309–334. 4. Sweet, D., and I. A. Pretty. 2001. A look at forensic dentistry—Part 2: Teeth as weapons of violence—Identification of bitemark perpetrators. British Dental Journal 190 (8): 415–418. 5. Pretty, I. A., and D. Sweet. 2001. The scientific basis for human bitemark analyses—A critical review. Science & Justice 41 (2): 85–92. 6. Pretty, I. A. 2006. The barriers to achieving an evidence base for bitemark analysis. Forensic Science International 159 (Suppl 1): S110–120. 7. Brunette, D. 1998. Critical thinking. London: Quintessence Books. 8. Rothwell, B. R. 1995. Bite marks in forensic dentistry: A review of legal, scientific issues. Journal of American Dental Association 126 (2): 223–232. 9. National Academy of Sciences. 2009. Strengthening forensic science in the United States: A path forward. Washington, D.C.: The National Academies Press. 10. Layton, J. J. 1966. Identification from a bite mark in cheese. Journal of Forensic Science Society 6 (2): 76–80. 11. Solheim, T., and T. I. Leidal. 1975. Scanning electron microscopy in the investigation of bite marks in foodstuffs. Forensic Science 6 (3): 205–215. 12. Sweet, D., and D. Hildebrand. 1999. Saliva from cheese bite yields DNA profile of burglar: A case report. International Journal of Legal Medicine 112 (3): 201–203. 13. Rudland, M. 1982. The dimensional stability of bite marks in apples after long-term storage in a fixative. Medicine Science and Law 22 (1): 47–50. 14. Simon, A., H. Jordan, and K. Pforte. 1974. Successful identification of a bite mark in a sandwich. International Journal of Forensic Dentistry 2 (3): 17–21. 15. Corbett, M. E., and D. Spence. 1984. A forensic investigation of teeth marks in soap. British Dental Journal 157 (8): 270–271. 16. Barbenel, J. C., and J. H. Evans. 1974. Bite marks in skin—Mechanical factors. Journal of Forensic Science Society 14 (3): 235–238.

Resolving Issues in Bitemark Analysis 17. Zhang, Z., and N. A. Monteiro-Riviere. 1997. Comparison of integrins in human skin, pig skin, and perfused skin: An in vitro skin toxicology model. Journal of Applied Toxicology 17 (4): 247–253. 18. Sheasby, D. R., and D. G. MacDonald. 2001. A forensic classification of distortion in human bite marks. Forensic Science International 122 (1): 75–78. 19. DeVore, D. T. 1971. Bite marks for identification? A preliminary report. Medicine Science and Law 11 (3): 144–145. 20. Vale, G. L., and T. T. Noguchi. 1983. Anatomical distribution of human bite marks in a series of 67 cases. Journal of Forensic Sciences 28 (1): 61–69. 21. Pretty, I. A., and D. Sweet. 2000. Anatomical location of bitemarks and associated findings in 101 cases from the United States. Journal of Forensic Sciences 45 (4): 812–814. 22. Bernstein, M. L. 1985. Two bite mark cases with inadequate scale references. Journal of Forensic Sciences 30 (3): 958–964. 23. Harvey, W. 1976. Dental identification and forensic odontology. London: Kimpton Publishers. 24. Hyzer, W. G., and T. C. Krauss. 1988. The bitemark standard reference scale—ABFO no. 2. Journal of Forensic Sciences 33 (2): 498–506. 25. Bush, M. A. et al. 2010. The response of skin to applied stress: Investigation of bitemark distortion in a cadaver model. Journal of Forensic Sciences 55 (1): 71–76. 26. Bush, M. A. et al. 2009. Biomechanical factors in human dermal bitemarks in a cadaver model. Journal of Forensic Sciences 54 (1): 167–76. 27. American Board of Forensic Odontology, Inc. 1986. Guidelines for bite mark analysis. Journal of American Dental Association 112 (3): 383–386. 28. Bernstein, M. L. 1983. The application of photography in forensic dentistry. Dental Clinics of North America 27 (1): 151–170. 29. Pretty, I. A., and D. Sweet. 2001. Digital bite mark overlays—An analysis of effectiveness. Journal of Forensic Sciences 46 (6): 1385–1391. 30. Bang, G. 1976. Analysis of tooth marks in a homicide case. Observations by means of visual description, stereophotography, scanning electron microscopy and stereometric graphic plotting. Acta Odontologica Scandinavica 34 (1): 1–11. 31. Jonason, C. O., K. O. Frykholm, and A. Frykholm. 1974. Three-dimensional measurement of tooth impression of criminological investigation. International Journal of Forensic Dentistry 2 (6): 70–78. 32. Jakobsen, J. et al. 1995. Scanning electron microscopy, a useful tool in forensic dental work. Journal of Forensic Odontostomatology 13 (2): 36–40. 33. Nambiar, P., T. E. Bridges, and K. A. Brown. 1995. Quantitative forensic evaluation of bite marks with the aid of a shape analysis computer program: Part 2. “SCIP” and bite marks in skin and foodstuffs. Journal of Foren sic Odontostomatology 13 (2): 26–32.

613 34. Nambiar, P., T. E. Bridges, and K. A. Brown. 1995. Quantitative forensic evaluation of bite marks with the aid of a shape analysis computer program: Part 1. The development of “SCIP” and the similarity index. Journal of Forensic Odontostomatology 13 (2): 18–25. 35. Barsley, R. E., M. H. West, and J. A. Fair. 1990. Forensic photography. Ultraviolet imaging of wounds on skin. American Journal of Forensic Medicine and Pathology 11 (4): 300–308. 36. Lightelm, A. J., W. J. Coetzee, and P. J. van Niekerk. 1987. The identification of bite marks using the reflex microscope. Journal of Forensic Odontostomatology 5 (1): 1–8. 37. Rao, V. J., and R. R. Souviron. 1984. Dusting and lifting the bite print: A new technique. Journal of Forensic Sciences 29 (1): 326–330. 38. Wood, R. E., P. A. Miller, and B. R. Blenkinsop. 1994. Image editing and computer assisted bitemark analysis: A case report. Journal of Forensic Odontostomatology 12 (2): 30–36. 39. Sweet, D., and C. M. Bowers. 1998. Accuracy of bite mark overlays: A comparison of five common methods to produce exemplars from a suspect’s dentition. Journal of Forensic Sciences 43 (2): 362–367. 40. Sweet, D., M. Parhar, and R. E. Wood. 1998. Computerbased production of bite mark comparison overlays. Journal of Forensic Sciences 43 (5): 1050–1055. 41. Dailey, J. C. 1991. A practical technique for the fabrication of transparent bite mark overlays. Journal of Forensic Sciences 36 (2): 565–570. 42. West, M. H. et al. 1990. The use of human skin in the fabrication of a bite mark template: Two case reports. Journal of Forensic Sciences 35 (6): 1477–1485. 43. Naru, A. S., and E. Dykes. 1996. The use of a digital imaging technique to aid bite mark analysis. Science & Justice 36 (1): 47–50. 44. Pretty, I. A., and R. C. Hall. 2002. Forensic dentistry and human bite marks: Issues for doctors. Hospital Medicine 63 (8): 476–482. 45. Naru, A. S., and E. Dykes. 1997. Digital image cross-correlation technique for bite mark investigations. Science & Justice 37 (4): 251–258. 46. Sweet, D. et al. 1997. An improved method to recover saliva from human skin: The double swab technique. Journal of Forensic Sciences 42 (2): 320–322. 47. Sweet, D. et al. 1997. PCR-based DNA typing of saliva stains recovered from human skin. Journal of Forensic Sciences 42 (3): 447–451. 48. Drinnan, A. J., and M. J. Melton. 1985. Court presentation of bite mark evidence. International Dental Journal 35 (4): 316–321. 49. Pretty, I. A. 2003. A Web-based survey of odontologists’ opinions concerning bitemark analyses. Journal of Forensic Sciences 48 (5): 1117–1120. 50. Pretty, I. A., and D. Sweet. 2001. A look at forensic dentistry—Part 1: The role of teeth in the determination of human identity. British Dental Journal 190 (7): 359–366.

614

Bitemark Evidence: A Color Atlas and Text, 2nd Edition

51. Bowers, C. M., and I. A. Pretty. 2009. Expert disagreement in bitemark casework. Journal of Forensic Sciences 54 (4): 915–918. 52. MacFarlane, T. W., D. G. MacDonald, and D. A. Sutherland. 1974. Statistical problems in dental identification. Journal of Forensic Science Society 14 (3): 247–252. 53. State v. Garrison, 120 Ariz. 255, 585 P.2d 563, 1978. 54. Sognnaes, R. F. et al. 1982. Computer comparison of bitemark patterns in identical twins. Journal of American Dental Association 105 (3): 449–451. 55. Rawson, R. D. et al. 1984. Statistical evidence for the individuality of the human dentition. Journal of Forensic Sciences 29 (1): 245–253. 56. Goldstein, M., D. J. Sweet, and R. E. Wood. 1998. A specimen positioning device for dental radiographic

identification—Image geometry considerations. Journal of Forensic Sciences 43 (1): 185–189. 57. Pretty, I. A. 2003. The use of dental aging techniques in forensic odontological practice. Journal of Forensic Sciences 48 (5): 1127–1132. 58. Bush, M. A., P. J. Bush, and H. D. Sheets. In press, 2011. Statistical evidence for the similarity of the human dentition. Journal of Forensic Sciences 56(1). 59. Keyes, F. A. 1925. Teeth marks on the skin as evidence in establishing identity. Dental Cosmos 67:1165–1167. 60. Aksu, M. N., and J. P. Gobetti. 1996. The past and present legal weight of bite marks as evidence [see comments]. American Journal of Forensic Medicine and Pathology 17 (2): 136–140.

Appendices

XIII

Appendix 1: ABFO Bitemark Analysis Guidelines—Outline*

Description of Bitemark 1. Identification data (case number, agency, name of examiner(s), etc.) 2. Location of bitemark • Anatomical location or object bitten • Surface contour (e.g., flat, curved, or irregular) • Tissue characteristics 3. Shape, color, and size 4. Type of injury (e.g., abrasion, contusion, and avulsion) 5. Other information as indicated (e.g., threedimensional characteristics, unusual conditions, derived from excised tissue, transillumination)

Bitemark Descriptive Terms

a. Class characteristics i. Shape ii. Size iii. Pattern b. Individual characteristics i. Arch characteristics ii. Dental characteristics c. Central ecchymosis d. Linear abrasions e. “Double bite” or multiple bites f. Avulsion

Evidence Collection and Exemplars c. Bitemark evidence protocol i. Double swab for salivary DNA ii. DNA preservation iii. Photograph injury iv. Soft-tissue impression v. Tissue excision and preservation

d. Photography i. ABFO ruler ii. Geometric distortion and parallax iii. Visible light technique iv. Alternative light techniques/sources, films, and filters e. Suspect evidence protocol i. Legal consent ii. Impression requirements iii. Study cast requirements iv. DNA collection v. Extraoral and intraoral exam vi. Bite registration vii. Excursion measurements

Bitemark Analysis and Comparison a. Metric analysis i. Teeth ii. Arch iii. Bite opening distance b. Pattern association i. Hollow volume transparencies ii. Full volume transparencies iii. Digital enhancement and superimposition iv. Test bites v. Transillumination vi. Scanning electron microscopy e. ABFO guidelines—confidence of existence of a bitemark i. Bitemark ii. Suggestive of a bitemark iii. Not a bitemark f. ABFO guidelines—confidence of link to suspect i. Reasonable medical certainty (beyond reasonable doubt) ii. Probable (more likely than not) iii. Exclusion (ruled out) iv. Inconclusive (insufficient evidence)

* The ABFO Bitemark Analysis Guidelines is copyrighted material and reprinted in outline form with kind permission from the American Board of Forensic Odontology, Inc. (June 1, 2009).

617

Appendix 2: ABFO Guidelines for Investigative and Final Bitemark Reports

The ABFO bitemark report writing guidelines propose a format for written bitemark reports. The guidelines are suggestions for the form and content of the report. Diplomates may be asked to provide preliminary or investigative reports. Preliminary reports may follow the same general guidelines without being conclusive in nature. Reports may be structured as follows:

Methods of analysis This section describes the analytic methods used for the patterned injuries determined to be bitemarks. Results of analyses This section describes the results of the comparisons and analyses.

Introduction This section provides the background information, the “who, what, when, where, and why” data related to the case.

Opinion This section states the author’s opinion of the relationship between one or more bitemarks and a suspected biter or biters using ABFO bitemark terminology. Only one comparative term is used for each opinion in this part of the report.

Inventory of evidence received This section lists all evidence received by the forensic odontologist and details the source of the evidence.

Disclaimer Disclaimer statements may be included to convey that the opinion or opinions are based upon the evidence reviewed through the date of the report. The author may reserve the right to file amended reports if additional evidence should become available.

Inventory of evidence collected This section lists the nature of, source of, and authority for evidence collected by the forensic odontologist. Opinion regarding the nature of the patterned injury or injuries This section states the author’s opinion as to whether the patterned injury is a bitemark, using ABFO terminology.

(October 4, 2010)

619

Appendix 3: Bitemark Checklist—Bitemark Recipient

Demographics Name of recipient _____________________________________________________________________________ Address _____________________________________________________________________________________ ____________________________________________________________________________________ Race _________ Gender _________ DOB ___/___/___ Age _________ Height _________ Weight ____________ Bitemark recipient alive ____ deceased ____ Date reported missing ___/___/___ Date of recovery ___/___/___ Police case no. ______________________________ Coroner/ME case no. ________________________________ Referring agency ______________________ TEL ______________________ FAX _________________________ Contact person _______________________________________________________________________________ TEL ________________ FAX ________________ CELL ________________ PAGE ________________________ Name of physician/pathologist ___________________________________________________________________ Address _____________________________________________________________________________________ _________________________________________E-mail _____________________________________________ TEL ________________ FAX ________________ CELL ________________ PAGE ________________________ Date/time/place of autopsy ___/___/___: _______: _ _________________________________________________ Cause of death ______________________________ Manner of death ___________________________________ Name of first dental examiner _ __________________________________________________________________ Dental examiner first contacted by ________________________________________________________________ Date of contact ___/___/___ Date/time/place of exam ___/___/___: __________: _ ________________________________________________ Officer in charge ______________________________________________________________________________ Address _____________________________________________________________________________________ _________________________________________E-mail _____________________________________________ TEL ________________ FAX ________________ CELL ________________ PAGE ________________________ Coroner/ME _________________________________________________________________________________ Address _____________________________________________________________________________________ _________________________________________E-mail _____________________________________________ TEL ________________ FAX ________________ CELL ________________ PAGE ________________________ Person authorizing billing _ _____________________________________________________________________ Prosecutor/__________________________________________________________________________________ Address _____________________________________________________________________________________ _________________________________________E-mail _____________________________________________ TEL ________________ FAX ________________ CELL ________________ PAGE ________________________ Case no. _______________________________ Court no. _____________________________________________ Brief description of facts: _______________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ 621

622 Appendix 3: Bitemark Checklist—Bitemark Recipient

Saliva Swab of Bite Site Swabs? Yes ____ No ____ If not, why not _ _________________________________________________________ Name of collector _____________________________________________________________________________ Are bite sites protected? No _____Yes/How _________________________________________________________ Site collection ________________________________________________________________________________ Control site: Yes ____ No ____ Where _ ___________________________________________________________ Date collected ___/___/___ Analysis by ________________________________________ Results _ __________________________________ Bitemark recipient’s blood type ____________________ Other bodily fluids collected? Yes ____ No ____ Where _ ____________________________________________

Photographic Documentation of the Bite Any prior photography? Yes ____ No ____ Name of person

Date

Time

Place

Date

Time

Place

Current photographs: Name of person 1. 2. Video Standard Digital Filters Color ALI UV IR Other

1. Make/type

No.

2. Make/type

No.

Scale ABFO no. 2 ___ Other __________________________________

Location and Description of Bitemark Any prior examination (other than dental examiner): Name of person

Date

Time

Place

Appendix 3: Bitemark Checklist—Bitemark Recipient

Anatomic location Clothing at bite site Surface contour Tissue: fixed/mobile Underlying tissue Shape of bitemark Size: vertical linear Size: horizontal linear Vertical circumferential Horizontal circumferential Color Petechial hemorrhage Contusion/ecchymosis Abrasion Laceration Incision Avulsion Indented without bruising Indented with bruising Perforation Superimposed marks Artifact Embalmed Lividity side noncontact Lividity side contact Type of mark: Animal Human Unknown Dental characteristics: Child Mixed Adult Infliction: self Infliction: second party Timing: Antemortem Timing: Postmortem BM/Body recov (dys-hrs) Body recov/exam(dys-hrs) Exam/excision (dys-hrs)

623

A

B

C

XXXXXXXXX

XXXXXXXXX

XXXXXXXXX

XXXXXXXXX

XXXXXXXXX

XXXXXXXXX

624 Appendix 3: Bitemark Checklist—Bitemark Recipient

Impressions Bitemark recipient’s dental impressions Yes ____ No ____ If not, why not _ _______________________________________________________________ Who took impressions? _ _______________________________________________________________________ Date/time/place _ _____________________________________________________________________________ Dental impression material, stone, other: Manufacturer

Type

Mfg. lot no.

Exp. date

Water/powder ratio _ __________________________________________________________________________ Wax bite _____ Aluwax _____ Styrofoam _____ Celluloid _____ Other ___________ Bitemark impressions Yes ____ No ____ If not, why not _ _______________________________________________________________ Who took impressions? _ _______________________________________________________________________ Date/time/place _ _____________________________________________________________________________ Dental impression material, stone, other: Manufacturer

Type

Mfg. lot no.

Exp. date

Tissue Specimens A

B

C

Bitemark excised by Date/time No excision Type of excision Fixative (name and percent) Transillumination SEM Histology Bacteriology Other Name of other specialist consulted: ___________________________________________________________________________________________ Address _____________________________________________________________________________________ __________________________ TEL __________________________ FAX _______________________________ (RBJD/2010)

Appendix 4: Bitemark Checklist—Suspected Biter

Demographics Name of suspected biter ________________________________________________________________________ Address_____________________________________________________________________________________ ____________________________________________________________________________________ Race _________ Gender _________ DOB ___/___/___ Age _________ Height _________ Weight ____________ Suspect alive ______ deceased ______ Police case no. _________________________________ Court no. ______________________________________ Contact person _______________________________________________________________________________ Address _____________________________________________________________________________________ _________________________________________E-mail _____________________________________________ TEL ________________ FAX ________________ CELL ________________ PAGE ________________________ Person authorizing billing _ _____________________________________________________________________ Address _____________________________________________________________________________________ _________________________________________E-mail _____________________________________________ TEL ________________ FAX ________________ CELL ________________ PAGE ________________________ Person/organization paying for the expertise ________________________________________________________ Address _____________________________________________________________________________________ _________________________________________E-mail _____________________________________________ TEL ________________ FAX ________________ CELL ________________ PAGE ________________________ Defense attorney______________________________________________________________________________ Address _____________________________________________________________________________________ _________________________________________E-mail _____________________________________________ TEL ________________ FAX ________________ CELL ________________ PAGE ________________________ Attorney case no. ____________________ Authorization for exam: Court order ____________________________________ No.__________________________________________ Search warrant __________________________________ No.__________________________________________ Informed consent: by suspect ___________________________ by guardian_______________________________ Other_______________________________________________________________________________________ Witness to consent

Date

Time

Place

Name of dental examiner_ ______________________________________________________________________ Dental examiner called by _ _____________________________________________________________________ Date/time/place of exam___/___/___: _______: _____________________________________________________ ___________________________________________________________________________________________

625

626 Appendix 4: Bitemark Checklist—Suspected Biter

Dental History Last dental appointment ________________________________________________________________________ Name of last treating dentist _____________________________________________________________________ Address of last dentist _ ________________________________________________________________________ Types of records available from last dentist _________________________________________________________ Nomenclature used in record: FDI _______________ Universal _______________ Other _ __________________ Dental record: Retained _______________ Seized _______________ Court order _ ________________________ Last date on record Medical history Written record Odontogram Radiograph Models/dental casts Dental impressions Dental photographs Other

Photographic Documentation of the Dentition Any prior photograph (other than current dental examiner) Name of person

Date

Time

Place

Current examiner photographs: Self _____ Name ____________________________________________________ Type

No.

Date

Time

Video Photographs Filters Lighting Other Type of photography Extraoral view: Centric occlusion Rest position Protrusive Edge to edge Intraoral view: Occlusal maxillary Occlusal mandibular Other

Front XXXXXXXXXX

Right XXXXXXXXXXX

Left XXXXXXXXXXX

XXXXXXXXXX

XXXXXXXXXXX

XXXXXXXXXXX

Appendix 4: Bitemark Checklist—Suspected Biter

Radiographs Standard x-rays Digital x-rays Other

Number/date

Number/date

627

Number/date

Clinical Exam Extraoral: TMJ Facial symmetry Muscle tone and balance Deviation on opening Max. vertical opening Surgery or trauma Facial hair Other Intraoral: Bite classification Occlusal disharmonies Tongue size, function Periodontal condition Missing teeth Broken teeth Tooth mobility Misalignment Restored teeth Dental charting

Normal

Abnormal

Remarks

Impressions I. Suspected biter’s dental impressions: Manufacturer

Type

Mfg. lot no.

Exp. date

Wax bite ________ Aluwax ________ Stryrofoam_________ Celluloid ________

Saliva Swab Swabs? Yes ____ No ____ If not, why not___________________________________________________________ Court order no._______________________________________________________________________________ Voluntary submission________ Date collected ___/___/___ Analysis by _____________________________________ Results_______________________________________

628 Appendix 4: Bitemark Checklist—Suspected Biter

II. Bitemark impression on suspect: This section is to be completed only if the suspect of a crime has been bitten by the victim of the crime. Bitemark impression material, stone, other: Manufacturer

Type

Mfg. lot no.

Exp. date

Water/powder ratio _ __________________________________________________________________________ Wax bite ________ Aluwax ________ Stryrofoam_________ Celluloid ________ Other ________ (RBJD/2010)

Appendix 5: Sample Consent Form

Declaration of Voluntary Acceptance for an Odontological Examination By the present, I, __________________________________________________________, the undersigned, authorize Dr. ______________________________________________ to perform the following: A) Take dental impressions B) A dental examination including the taking of radiographs C) Take a video and pictures of my dentition D) Visually examine any and all corporal wounds E) Take impressions of any and all corporal wounds F) Take a video and pictures of any and all corporal wounds G) Take saliva samples H) Take samples of substances on the surface of my body I) Other:_ __________________________________________________________________________________ I hereby voluntarily accept, without duress, coercion, threats, or promises of reward or immunity, to undergo these examinations. I do hereby release and forever hold harmless Dr. ______________________________________ from any and all liability flowing from these examinations and results. I further agree that the results of these examinations may be made available to competent authorities for judicial, scientific, and publication purposes. Witness: 1)__________________________________________________________________________________________ 2)__________________________________________________________________________________________ Date: ___________________________________ Time: _ _________________________________ Place: _ _________________________________ Signature ______________________________________

629

Appendix 6: Dental Nomenclature

Dental Conversion Table for Tooth Designation Deciduous Dentition Upper right

Upper left

Palmer

E+

D+

C+

B+

A+

+A

+B

+C

+D

+E

F.D.I.

55

54

53

52

51

61

62

63

64

65

Hareup

05+

04+

03+

02+

01+

+01

+02

+03

+04

+05

Other

V

IV

III

II

I

I

II

III

IV

V

Other

5D

4D

3D

2D

1D

1D

2D

3D

4D

5D

Other

d5

d4

d3

d2

d1

d1

d2

d3

d4

d5

Other

5m

4m

3m

2m

1m

1m

2m

3m

4m

5m

Other

A

B

C

D

E

E

D

C

B

A

Other

dm2

dm1

dc

di2

di1

di1

di2

dc

dm1

dm2

F.D.I. (modified)

55

54

53

52

51

61

62

63

64

65

Other

E

D

C

B

A

A

B

C

D

E

Lower right

Lower left

Palmer

E–

D–

C–

B–

A–

–A

–B

–C

–D

–E

F.D.I.

85

84

83

82

81

71

72

73

74

75

Hareup

05–

04–

03–

02–

01–

–01

–02

–03

–04

–05

Other

V

IV

III

II

I

I

II

III

IV

V

Other

5D

4D

3D

2D

1D

1D

2D

3D

4D

5D

Other

d5

d4

d3

d2

d1

d1

d2

d3

d4

d5

Other

5m

4m

3m

2m

1m

1m

2m

3m

4m

5m

Other

A

B

C

D

E

E

D

C

B

A

Other

dm2

dm1

dc

di2

di1

di1

di2

dc

dm1

dm2

F.D.I. (modified)

75

74

73

72

71

81

82

83

84

85

Other

E

D

C

B

A

A

B

C

D

E

Source: Dorion, R. B. J. 1975. Dental nomenclature. Canadian Society of Forensic Science Journal 8 (3): 107–110. Reprinted with kind permission.

631

632 Appendix 6: Dental Nomenclature Dental Conversion Table for Tooth Designation Permanent Dentition

2nd Molar

1st Molar

2nd Bicuspid

1st Bicuspid

Cuspid

Lateral

Central

Central

Lateral

Cuspid

1st Bicuspid

2nd Molar

1st Bicuspid

2nd Molar

3rd Molar

Upper left

3rd Molar

Upper right

UR8

UR7

UR6

UR5

UR4

UR3

UR2

UR1

UL1

UL2

UL3

UL4

UL5

UL6

UL7

UL8

Hareup

8+

7+

6+

5+

4+

3+

2+

1+

+1

+2

+3

+4

+5

+6

+7

+8

Palmer

8|

7|

6|

5|

4|

3|

2|

1|

1|

2|

3|

4|

5|

6|

7|

8|

Universal

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

F.D.I.

18

17

16

15

14

13

12

11

21

22

23

24

25

26

27

28

U.S. Army

8

7

6

5

4

3

2

1

1

2

3

4

5

6

7

8

U.S. Navy

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

Bosworth

8

7

6

5

4

3

2

1

1

2

3

4

5

6

7

8

Lowlands

M3

M2

M1

P2

P1

C

12

11

11

12

C

P1

P2

M1

M2

M3

Some European countries

D8

D7

D6

D5

D4

D3

D2

D1

G1

G2

G3

G4

G5

G6

G7

G8

sdP2

sdP1

sdC

sd12

sd11

sg11

sg12

sgC

sgP1

sgP2

Miscellaneous

Holland

sdM3 sdM2 sdM1

sgM1 sgM2 sgM3

F.D.I (modified)

18

17

16

15

14

13

12

11

21

22

23

24

25

26

27

28

Other

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

Lower right

Lower left

Other

32

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

F.D.I. (modified)

38

37

36

35

34

33

32

31

41

42

43

44

45

46

47

48

diP2

diP1

diC

dil2

dil1

gil1

gil2

giC

giP1

giP2

Holland

diM3 diM2 diM3

giM1 giM2 giM3

Some European countries

d8

d7

d6

d5

d4

d3

d2

d1

g1

g2

g3

g4

g5

g6

g7

g8

Lowlands

M3

M2

M1

P2

P1

C

12

11

11

12

C

P1

P2

M1

M2

M3

Bosworth

H

G

F

E

D

C

B

A

A

B

C

D

E

F

G

H

U.S. Navy

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

U.S. Army

16

15

14

13

12

11

10

9

9

10

11

12

13

14

15

16

F.D.I.

48

47

46

45

44

43

42

41

31

32

33

34

35

36

37

38

Universal

32

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

Palmer

8|

7|

6|

5|

4|

3|

2|

1|

1|

2|

3|

4|

5|

6|

7|

8|

Hareup

8–

7–

6–

5–

4–

3–

2–

1–

–1

–2

–3

–4

–5

–6

–7

–8

LR8

LR7

LR6

LR5

LR4

LR3

LR2

LR1

LL1

LL2

LL3

LL4

LL5

LL6

LL7

LL8

Miscellaneous

Source: Dorion, R. B. J. 1975. Dental nomenclature. Canadian Society of Forensic Science Journal 8 (3): 107–110. Reprinted with kind permission.