9781422273463

Impression Evidence Identifying Fingerprints, Bite Marks, and Tire Treads

Crime Scene Collecting Physical Evidence Digital Forensics

Investigating Data DNA Profiling

Linking the Suspect to the Evidence Forensic Anthropology Identifying Human Remains Forensic Chemistry Detecting Drugs and Poisons Forensic Psychology

Probing the Criminal Mind Impression Evidence Identifying Fingerprints, Bite Marks, and Tire Treads Pathology Examining the Body for Clues

Impression Evidence Identifying Fingerprints, Bite Marks, and Tire Treads

By Katherine Lacaze

MASON CREST PH I L ADELPH I A | MI AMI

Mason Crest PO Box 221876, Hollywood, FL 33022 (866) MCP-BOOK (toll-free) • www.masoncrest.com

Copyright © 2022 by Mason Crest, an imprint of National Highlights, Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, taping, or any information storage and retrieval system, without permission in writing from the publisher. Printed in the United States of America First printing 9 8 7 6 5 4 3 2 1 Series ISBN: 978-1-4222-4464-7 Hardcover ISBN: 978-1-4222-4471-5 ebook ISBN: 978-1-4222-7346-3 Cataloging-in-Publication Data on file with the Library of Congress

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Introduction: The Value of a Lasting Impression . ................. 7 Chapter 1: Fingerprints ......................................................... 17 Chapter 2: Bite Marks ............................................................ 31 Chapter 3: Footprints and Shoe Marks . .............................. 45 Chapter 4: Tire Treads . ......................................................... 59 Chapter 5: Tool Marks ............................................................ 73 Series Glossary of Key Terms ................................................. 86 Further Reading & Internet Resources ................................. 90 Index . ........................................................................................ 92 Author’s Biography ................................................................. 95 Credits . ..................................................................................... 96 K E Y I C O N S T O L O O K F O R Words to Understand: These words with their easy-to-understand definitions will increase reader’s understanding of the text while building vocabulary skills. Sidebars: This boxed material within the main text allows readers to build knowledge, gain insights, explore possibilities, and broaden their perspectives by weaving together additional information to provide realistic and holistic perspectives. Educational Videos: Readers can view videos by scanning our QR codes, providing them with additional educational content to supplement the text.

Text-Dependent Questions: These questions send the reader back to the text for more careful attention to the evidence presented there.

Research Projects: Readers are pointed toward areas of further inquiry connected to each chapter. Suggestions are provided for projects that encourage deeper research and analysis. Series Glossary of Key Terms: This back-of-the-book glossary contains terminology used throughout this series. Words found here increase the reader’s ability to read and comprehend higher-level books and articles in this field.

Impression evidence encompasses any object leaving an indentation or print—an “impression.”

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The Value of a Lasting Impression Forensic scientists rely on a variety of evidence to participate in the crime investigation process, as well uphold justice by helping to bring about convictions for the guilty and acquittals for the innocent. Among the different types of evidence that investigators collect, analyze, and record is impression evidence, which encompasses any markings that are produced when one object comes into contact with another, leaving behind some sort of indentation or print—an “impression.” According to the National Institute of Justice, impression evidence is one of the most common forms of evidence that investigators may detect and collect at a crime scene. It can be either two-dimensional or three-dimensional, encompassing fingerprints, bite marks, footprints, tool marks, and tire marks. Impressions get left behind in or on a wide variety of different materials at crime scenes, which can affect the methods used to collect and preserve said evidence. From within a collection of impression evidence, forensic scientists can further detect different types of patterns that provide identifying information related to the object that left the mark and potentially its owner. Shoes, tires, tools, and fingerprints all have unique patterns that can help investigators narrow down their search for a suspect, or help link a tool to a particular crime. In many cases, the term “impression evidence” is meant to encompass pattern evidence, although they are technically two distinct yet related categories. Tires, tools, and shoes leave impressions that are categorized as “class evidence,” meaning they have characteristics that place or restrict the evidence to a particular group of objects, such as trucks, pliers, or boots. “Individual evidence,” on the other hand, such as fingerprints, possesses characteristics that can narrow it down to one specific person. Sometimes impression evidence may have both class and individual characteristics. For example, if a tool used for a crime has a unique flaw that affects the impression or the pattern within it, then tool mark examiners could use that information to not only determine the tool that left the mark but possibly also help link one specific tool to the crime. Regardless of whether it has primarily class or individual characteristics, each piece of evidence is valuable in its own way. It can prove certain facts

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or disprove others. It can solidify a timeline or support an alibi. It can give investigators a clearer picture of what happened when, where, and by whom. Sometimes, a piece of evidence merely gives investigators a new lead to follow or reveals that a lead they’re chasing is a dead end. Other times, that impression left behind at the scene of the crime may be the piece of evidence that, when presented in court, convinces the jury of a particular verdict. Because impression evidence is valuable within the criminal justice world, forensic scientists must have the right skills, knowledge, and tools to properly collect, record, analyze, and interpret it. They initially develop their skills through adequate education and on-the-job training and then continue to build on and expand their knowledge base throughout the course of their career. As technology and science evolve, new opportunities may also emerge within the field of forensic science. On the Job: Forensic Scientists Forensic scientists or technicians may encounter or deal with impression evidence during the process of searching a crime scene. More often, however, they will specialize in a particular area. For example, there are forensic fingerprint experts and tool mark examiners who specialize in that specific type of evidence and will be called to a crime scene if those kinds of impressions are detected. “Forensic science,” or “criminalistics,” is the general term for the application of various scientific principles and techniques to the criminal justice world—particularly relating to the collection, examination, and analysis of physical evidence from crime scenes. Across literature and in the field, forensic scientists may also be referred to as “criminalists,” “forensic analysts,” “crime scene investigators,” or “lab techs.” More specific terms become applicable if a forensic scientist pursues a particular subdiscipline, such as pathology, toxicology, or fingerprint identification. For example, all forensic toxicologists are forensic scientists, but not all forensic scientists are forensic toxicologists. In general, all forensic scientists must acquire at least a bachelor’s degree from an accredited college or university. Optimal fields of study for individuals who want to become experts in a category of impression evidence include physical or natural sciences, criminal justice, biological sciences, or forensic science. However, fingerprint analysts and forensic footwear and tire tread examiners may also use chemical treatments to aid in the discovery and analysis of prints. The American Academy of Forensic Sciences encourages students who are interested in careers as forensic analysts to study a range of topics, including math, chemistry,

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Impression Evidence

In general, all forensic scientists must acquire at least a bachelor’s degree from an accredited college or university.

criminalistics, and biological sciences. Meanwhile, individuals who want to work in the field of forensic dentistry must possess a Doctor of Dental Surgery (DDS) or Doctor of Medicine in Dentistry (DMD) degree. Some forensic specialists must become certified by a board, such as the American Board of Forensic Odontology, or complete specific Federal Bureau of Investigation (FBI) or Department of Justice (DOJ) courses to help them prepare for certification. There are various professional organizations that offer forensic analysts the ability to become certified in their particular subdiscipline. These include the International Association of Identification, the American Academy of Forensic Science, and the Association of Firearm and Tool Mark Examiners. Certifications are valuable because they demonstrate that a forensic scientist has truly achieved a certain level of expertise in a particular field. They are also opportunities for continuing professional development to help forensic analysts stay up to date with the most recent science and technology that is applicable to their work. In addition to education and certification, expert forensic analysts—both those who investigate crime scenes and those who work in labs—must also obtain practical, on-the-job training.

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Introduction: The Value of a Lasting Impression

In addition to education and certification, expert forensic analysts must obtain practical, on-the-job training.

The Job Market for Forensic Scientists The U.S. Bureau of Labor Statistics lumps all forensic scientists, also known as “crime scene investigators” or “forensic science technicians,” into one category rather than separating them out by job role. As of 2018, there were about 16,700 people employed in various forensic science roles. According to the bureau, the job outlook is fairly positive, as the field is estimated to grow by about 14 percent between 2018 and 2028, which is faster than the average for other industries. Since this is a relatively small field, however, that will only amount to an additional 2,400 jobs. Prospective forensic scientists and analysts can find employment with local and state governments and law enforcement agencies. The FBI also has specialized units devoted to particular types of impression evidence, such as the Latent Print Unit (LPU) and the Firearms/Toolmarks Unit (FTU). Smaller agencies may send their evidence to the FBI for expert analysis that requires a particular skill set.

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Impression Evidence

Specialists may choose to work in the field where they’re doing hands-on work, visiting crime scenes, and analyzing evidence in the lab. Others may pursue the research side of forensic science, contributing to the creation of more precise and accurate methods for analyzing and interpreting impression evidence. How Is Impression Evidence Used in Court? As with any type of evidence, an item is only as good as its interpretation. It’s not enough to simply collect and record impression evidence. Forensic experts must then use their extensive knowledge in their

Determining What Evidence Is Allowed in Court

Not every type of evidence that is currently presented in court in conjunction with criminal cases was always allowed. When a new type of technique or practice is introduced—such as collecting fingerprints or shoeprints—it can take a while for it to be considered a valid form of evidence in the legal world. Two court cases, Daubert v. Merrell Dow Pharmaceuticals Inc. (1993) and Frye v. United States (1923), have set precedents that are adhered to by various states, although the U.S. Supreme Court determined Daubert supersedes Frye at the federal level. Rule 702 of the Federal Rules of Evidence, which codify the introduction of evidence for civil and criminal trials in the U.S. federal courts, determines who is qualified as an expert witness for a case. The rule states that a witness is qualified as an expert based on a few criteria: their scientific, technical, or other specialized knowledge will help the trial’s trier of fact (the person or group of people who determine what is or is not a fact in a case) to understand the evidence or to determine a fact in issue; the testimony is based on sufficient facts or data; the testimony is the product of reliable principles and methods; and the expert has reliably applied the principles and methods to the facts of the case.

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Introduction: The Value of a Lasting Impression

If evidence gets mishandled while being transported to, or analyzed at, the lab, it may no longer be useful to the case.

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Impression Evidence

respective discipline to analyze the evidence and figure out how it fits into the bigger picture. It is essential that forensic scientists use the right techniques and instruments for collecting and preserving evidence for it to be admissible in court. If there are problems with the manner in which evidence was collected from the crime scene, or if it gets mishandled while being transported to, or analyzed at, the lab, it may no longer be useful to the case. Forensic scientists must stay up to date with the most reliable techniques and instruments, as well as scientific theories, that apply to their practice and use them consistently. Otherwise, their work on a case becomes compromised, and they could eventually lose their credibility. If a piece of evidence becomes central to the case and the case goes to court, forensic scientists may then be asked to give their expert testimony, explaining why that particular tire mark or fingerprint proves a certain point. Forensic scientists can give expert testimony for either the prosecution or the defense depending on the case, but ultimately their job is to give honest, unbiased interpretations of the evidence that help guide the jury as they make a decision regarding the verdict. In such cases, it is critical for forensic scientists to be completely objective as they present the evidence and not allow their interpretation of the evidence to be swayed by any personal bias or external pressure. Courtrooms can also be intense, even contentious environments. As expert witnesses in criminal cases, forensic scientists will be questioned and cross-examined by both the defense and prosecution. Individuals who want to pursue a career in this field must have a certain level of stamina and tenacity, as well as the ability to stay calm and controlled under pressure, if they want to be successful. They must have a thorough understanding of the scientific methods and principles used to collect, analyze, and interpret evidence so they can sufficiently explain it to members of the jury. To that end, forensic specialists should have strong written and verbal communication skills, for both writing reports and presenting in court. A Developing Field Forensic science is not infallible. Even though the practice is centuries old, new technology and scientific discoveries continue to highlight flaws in the system while offering more accurate solutions and practices for the future. These flaws can be disheartening to newcomers, especially if they’ve resulted in wrongful convictions or in evidence not being allowed

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Introduction: The Value of a Lasting Impression

Forensic specialists should have strong written and verbal communication skills, for both writing reports and presenting evidence in court.

in court because of how it was collected. However, forensic science also offers a wealth of opportunity for refinement and advancement that dedicated practitioners can help bring about with the right mindset and approach to their work. Each new forensic scientist can commit to using the best practices in the field and to upholding a high standard of integrity and objectivity while on the job. They can also contribute toward making improvements by identifying flaws in the system and crafting new solutions, methods, or practices to fix them. With this level of commitment from each forensic expert, the field has the potential to continue evolving, become more efficient, and fulfill its purpose of helping to maintain justice.

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Impression Evidence