Trace Evidence, Revised Edition

Max Houck, Max Hauck

Description

Evidence that can barely be seen with the naked eye routinely plays a crucial part in the search for—and the conviction of—some of the most dangerous criminals known to society. From the hairs of a dog to tiny fiber fragments, forensic analysts study these trace materials and interpret them for use in legal proceedings. Hairs and fibers are two of the most commonly found types of trace evidence and the focus of this eBook.

Trace Evidence, Revised Edition explores the microscopic world in which the forensic scientist works by addressing the issues of what constitutes evidence; important methods of trace analysis, including spectroscopy and chromatography; human and animal hairs and what can be determined by examining them; and manufactured and natural fibers and the many ways in which they appear in textiles and are analyzed in the laboratory. Written by a well-respected author with extensive knowledge in the field, this eBook is essential for students fascinated by this area of forensic science.

Chapters include:

• What Is Evidence?


• Forensic Applications


• Hairs


• Fibers.

Sujets

• Forensics
• Forensic Science
• Young Adult Nonfiction
• Sciences et techniques
• Evidence
• Crime
• Médecine légale
• Nature
• Science

Informations

• Publié par: Infobase Publishing
• Date de parution: 01 octobre 2019
• Nombre de lectures: 0
• EAN13: 9781438182643
• Langue: English

Extrait

Trace Evidence, Revised Edition
Copyright © 2019 by Max M. Houck
All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the publisher. For more information, contact:
Chelsea House An imprint of Infobase 132 West 31st Street New York NY 10001
ISBN 978-1-4381-8264-3
You can find Chelsea House on the World Wide Web at http://www.infobase.com
Contents Chapters What Is Evidence? Forensic Applications Hairs Fibers Support Materials Glossary Further Reading Index
Preface

Forensic science has become in the early 21st century what the space race was in the 1960s—an accessible and inspiring window into the world of science. The surge in popularity that began in the latter part of the 20th century echoes a boom that began in the later part of the 19th century and was labeled the "Sherlock Holmes effect." Today it is called the "C.S.I. effect," but the consequences are the same as they were a century ago. The public has developed a seemingly insatiable appetite for anything forensic, be it fiction, reality, or somewhere between.
Essentials of Forensic Science is a set that is written in response to this thirst for knowledge and information. Written by eminent forensic scientists, the books cover the critical core of forensic science from its earliest inception to the modern laboratory and courtroom.
Forensic science is broadly defined as the application of science to legal matters, be they criminal cases or civil lawsuits. The history of the law dates back to the earliest civilizations, such as the Sumerians and the Egyptians, starting around 5000 B.C.E. The roots of science are older than civilization. Early humans understood how to make tools, how to cook food, how to distinguish between edible and inedible plants, and how to make rudimentary paints. This knowledge was technical and not based on any underlying unifying principles. The core of these behaviors is the drive to learn, which as a survival strategy was invaluable. Humans learned to cope with different environments and conditions, allowing adaptation when other organisms could not. Ironically, the information encoded in human DNA gives us the ability to analyze, classify, and type it.
Science as a formalized system of thinking can be traced to the ancient Greeks, who were the first to impose systematic patterns of thought and analysis to observations. This occurred around 500 B.C.E. The Greeks organized ideas about the natural world and were able to conceive of advanced concepts. They postulated the atom (from the Greek word atomos ) as the fundamental unit of all matter. The Greeks were also among the first to study anatomy, medicine, and physiology in a systematic way and to leave extensive written records of their work. They also formalized the concept of the autopsy.
From ancient roots to modern practice the history of forensic science winds through the Middle Ages, alchemy, and the fear of poisoning. In 1840 pivotal scientific testimony was given by Mathieu-Joseph-Bonaventure (Mateu Josep Bonaventura) Orfila (1787–1853) in a trial in Paris related to a suspected case of arsenic poisoning. His scientific technique and testimony marks the beginning of modern forensic science. Today the field is divided into specialties such as biology (DNA analysis), chemistry, firearms and tool marks, questioned documents, toxicology, and pathology. This division is less than a half-century old. In Orfila's time the first to practice forensic science were doctors, chemists, lawyers, investigators, biologists, and microscopists with other skills and interests that happened to be of use to the legal system. Their testimony was and remains opinion testimony, something the legal system was slow to embrace. Early courts trusted swearing by oath—better still if oaths of others supported it. Eyewitnesses were also valued, even if their motives were less than honorable. Only in the last century has the scientific expert been integrated into the legal arena with a meaningful role. Essentials of Forensic Science is a distillation of the short history and current status of modern forensic science.
Trace Evidence by Max Houck. This book examines the common types of microscopic techniques used in forensic science, including scanning electron microscopy and analysis of microscopic evidence, such as dust, building materials, and other types of trace evidence.
Each volume begins with an overview of the subject, followed by a discussion of the history of the field and mention of the pioneers. Since the early forensic scientists were often active in several areas, the same names will appear in more than one volume. A section on the scientific principles and tools summarizes how forensic scientists working in that field acquire and apply their knowledge. With that foundation in place the forensic application of those principles is described to include important cases and the projected future in that area.
Finally, it is important to note that the volumes and the set as a whole are not meant to serve as a comprehensive textbook on the subject. Rather, the set is meant as a "pocket reference" best used for obtaining an overview of a particular subject while providing a list of resources for those needing or wanting more. The content is directed toward nonscientists, students, and members of the public who have been caught up in the current popularity of forensic science and want to move past fiction into forensic reality.
Acknowledgments

I want to thank my wife, Lucy, for understanding my bouts of alternating joy and grief during this project. All of my students in my courses at West Virginia University deserve thanks for helping me to understand, explain, reduce, refine, and reabsorb the fundamentals of what forensic science is. Students are always the best teachers; you can quote me on that. I must thank the tireless efforts of Frank Darmstadt, executive editor, to work with me to get the manuscript into shape, and Suzie Tibor, who brought a professional touch to conducting photo research. Finally, I want to thank my agent, Jodie Rhodes, for keeping me in line; I'm sorry I make you work so hard, Jodie.
Introduction

Hairs from a dog in Australia help to convict a young man for killing his mother and her husband. Carpet fibers from an automobile lead police to a serial child rapist. Two men are in a car when it crashes—one dies and the survivor says the dead man was driving, but clothing fibers and impressions from a pair of jeans determine if he is telling the truth. Tiny fiber fragments seal the fate of a man who kidnapped, molested, and killed a young girl. A single hair tips the scales of a killer's conscience and convinces him to confess.
Evidence that can barely be seen with the naked eye routinely plays a part in the search for and conviction of some of the most dangerous criminals known to society. How do forensic scientists know what to look for? How do they identify these miniscule bits of debris that give the courts and jury the information they need?
Trace Evidence is about the science of trace evidence and the forensic analysis of hairs and fibers. In plain terms, trace evidence is the bits of stuff that break off from a source and transfer to another location, sticking there until removed. Forensic analysts can trace these bits to their source (most of the time) and demonstrate the association between the source and the location where they were found. Two of the most commonly found types of trace evidence, and those that are the focus of this book, are hairs and fibers.
Hairs are a complicated biological structure and can make good evidence, whether they come from animals or humans. Using a microscope, a forensic scientist can tell a lot about a hair, including what part of the body it came from and whether it was cut with scissors or a razor. New types of DNA methods can analyze hairs for their genetic content, unlike older methods. Textile fibers have been with humans ever since our species left the tropics and needed clothing for warmth and protection. Fibers come from diverse natural sources, such as plants and animals, as well as "unnatural" sources: human industry. Many modern fibers are manufactured and some are entirely synthetic (made from chemical processes).
It is the forensic analyst's role to study these trace materials and interpret them for use in legal proceedings. Hairs and fibers are first analyzed with a microscope and then by other means: DNA for hairs, chemistry instrumentation for fibers. It is important to understand the methods used to scrutinize hairs and fibers because what a forensic scientist can or cannot say in court comes directly from those methods. A faulty analysis or a wrong interpretation can send the wrong person to jail or release a deadly criminal back into society. On television, forensic science is portrayed as a matter of sexy outfits, cool sunglasses, and quick science. In practice, forensic science can involve long hours of painstaking examination, gory details, and unpleasant circumstances. But it is a powerful method of assisting the courts in handing out justice, and is not to be taken lightly.
Trace Evidence covers two types of trace evidence: hairs and fibers. It may seem strange to focus on only two types of evidence but, as you will see, the complexity of just these two materials is enough to fill a book! To cover all the types of trace evidence would take many more books. Most materials, most things, are much more complicated than people imagine—the objects in our daily lives are taken for granted. Forensic scientists must learn a lot about many things to do their job well. Understanding the importance of two minute types of evidence is key to appreciating how very small things can make a big differen