ForensicsFOR

DUMmIES‰

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by D. P. Lyle, M. D.Author of Murder and Mayhem: A Doctor Answers Medical and

Forensic Questions for Mystery Writers

ForensicsFOR

DUMmIES‰

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Forensics For Dummies®

Published byWiley Publishing, Inc.111 River St.Hoboken, NJ 07030-5774www.wiley.com

Copyright © 2004 by Wiley Publishing, Inc., Indianapolis, Indiana

Published by Wiley Publishing, Inc., Indianapolis, Indiana

Published simultaneously in Canada

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About the AuthorDouglas Lyle was born and raised in Huntsville, Alabama, where his child-hood interests revolved around football, baseball, and building rockets in hisbackyard. The latter pursuit was common in Huntsville during the 1950s and’60s because of the nearby NASA/Marshall Space Flight Center.

After leaving Huntsville, he attended college, medical school, and served aninternship at the University of Alabama, which was followed by a residency ininternal medicine at the University of Texas at Houston, and a fellowship incardiology at The Texas Heart Institute, also in Houston. During the past 25years, he has practiced cardiology in Orange County, California.

Dr. Lyle currently is working on his fourth novel and writes “The Doctor Is In,”a monthly medical and forensic Q & A column that appears in the newslettersof several regional chapters of Mystery Writers of America.

His book Murder and Mayhem: A Doctor Answers Medical and ForensicQuestions for Mystery Writers is a compilation of the most interesting ques-tions he’s received through the years. His two thrillers Devil’s Playground andDouble Blind were released in 2003.

Through his Web site The Writers’ Medical and Forensics Lab (www.dplylemd.com), he works with writers to enrich their understanding of complex medicaland forensic issues in the stories they create. He also has worked with manypublished authors and with the writers and producers of several populartelevision shows, including Law and Order, Diagnosis Murder, Monk, JudgingAmy, Peacemakers, 1-800-Missing, and CSI: Miami.

In addition to reading and writing, his current interests include blues guitar,golf, travel, and collecting vintage guitars. He shares his life with Nan andthree cats: Missy (a.k.a. Miss Priss), a gray Abyssinian; Ozzie (a.k.a. Peanut),an Ocicat who fancies himself a member of the Raptor family; and Bennie(a.k.a. The Bean), a Bengal who is nocturnal to a fault.

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DedicationI dedicate this book to all who are driven by curiosity and a need to knowmore. My sincerest hope is that this work both scratches and stimulates thatitch.

Author’s AcknowledgmentsThis book would not have been possible without the help of many people. Toeach I give my sincerest thanks.

My agent and friend, Kimberley Cameron with Reece Halsey North. FromWiley Publishing, Inc., my very patient editors, Traci Cumbay and Kathy Cox,who worked diligently to bring this project to fruition. Their professionalism,guidance, and enthusiasm have proven invaluable.

My parents, Victor and Elaine, who not only gave a lifetime of guidance andsupport but also paid for my education. My sisters, Vicki, a talented and pro-fessional teacher, and Melinda, an artist in a wide variety of areas.

Nan, my better half, who gave me support and allowed me the freedom topursue the madness of writing and who provided the illustrations for thisbook. Our feline children, Missy, Peanut, and Bennie, who always make melaugh.

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Publisher’s AcknowledgmentsWe’re proud of this book; please send us your comments through our Dummies online registrationform located at www.dummies.com/register/.

Some of the people who helped bring this book to market include the following:

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Foreword

It used to be you could read a good mystery novel or watch a TV cop showand have a shot at solving the crime yourself. You can’t do that anymore . . .

not unless you happen to have a crime lab in your family room. Today, youneed to be a forensics expect to understand, much less enjoy, a detectivestory. But thanks to D.P. Lyle, you won’t feel like a dummy any more.

This book is a graduate school education in the intricacies of forensics. It’s amust-have resource for writers of detective fiction as well as an essentialcheat-sheet for the average viewer or reader of murder mysteries, and it’swritten in a casual, easy-to-read style that belies the detail and depth of theinformation it provides.

Both readers and writers of detective fiction will find that one copy ofForensics For Dummies just isn’t enough. You’ll need one for the recliner andone for the nightstand, within easy each to make sense of whatever thrilleryou’re watching, reading, or writing.

Lost in an episode of CSI? Baffled by the latest Patricia Cornwell thriller?Boggled by the documentaries on Discovery Channel? Finally, someone hascome along to explain to us, in simple English, the inexplicably complex gob-bledy-gook of forensics, the foreign language all the detectives in books, TVshows, and movies are speaking these days.

— Writer/producer Lee Goldberg, whose credits include Diagnosis Murder,Nero Wolfe, 1-800-Missing, and Monk.

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Contents at a GlanceForeword ....................................................................xxi

Introduction .................................................................1

Part I: Cracking Open the Case .....................................5Chapter 1: Understanding the World of Forensics ........................................................7Chapter 2: Uncovering Who Does What When: The Forensics Team in Action ......17Chapter 3: Working the Scene: Evidence Collection and Protection ........................29Chapter 4: Peering into the Criminal Mind ..................................................................49

Part II: Uncovering the Evidence .................................71Chapter 5: Fingerprints: Your Personal Signature .......................................................73Chapter 6: Those Messy Bloodstains ...........................................................................85Chapter 7: Making Good Impressions: Shoes, Tires, and Tools .................................99Chapter 8: The Burning Question: Is It Arson? ..........................................................113

Part III: Looking at the Body ....................................127Chapter 9: Determining the Hows and Whys of Death: Forensic Autopsies ..........129Chapter 10: Identifying John and Jane Doe ................................................................143Chapter 11: Estimating the Time of Death .................................................................161Chapter 12: Yeow! That Hurts: Traumatic Injuries and Deaths ...............................175Chapter 13: Asphyxia: Where’s the Oxygen? .............................................................195

Part IV: Working in the Crime Lab ............................211Chapter 14: Working with Blood and Other Bodily Fluids: Serology ......................213Chapter 15: What’s the Deal with DNA? ......................................................................227Chapter 16: Finding Drugs and Poisons: The Toxicology Lab .................................243Chapter 17: Analyzing Trace Evidence .......................................................................265Chapter 18: Going Ballistic: Analyzing Firearms Evidence .......................................283Chapter 19: Questioning the Validity of Documents .................................................295

Part V: The Part of Tens ...........................................309Chapter 20: Ten Famous Forensic Cases ....................................................................311Chapter 21: Ten Ways Hollywood Gets It Wrong .......................................................323Chapter 22: Ten Great Forensic Careers .....................................................................329

Index .......................................................................337

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Table of ContentsForeword.....................................................................xxiIntroduction..................................................................1

About This Book ...............................................................................................1Conventions Used in This Book .....................................................................1What You’re Not to Read .................................................................................2Foolish Assumptions ........................................................................................2How This Book Is Organized ...........................................................................2

Part I: Cracking Open the Case .............................................................2Part II: Uncovering the Evidence ..........................................................3Part III: Looking at the Body ..................................................................3Part IV: Working in the Crime Lab ........................................................3Part V: The Part of Tens .........................................................................3

Icons Used in This Book ..................................................................................4Where to Go from Here ....................................................................................4

Part I: Cracking Open the Case ......................................5

Chapter 1: Understanding the World of Forensics . . . . . . . . . . . . . . . . . .7Defining Forensics: The Science of Catching Criminals ..............................7

Integrating science into the practice of law ........................................8Drawing from other sciences ................................................................9

Getting the Big Picture: Forensics in Action .................................................9Starting out small: Basic forensic services .......................................10Finding out about physical forensic science .....................................10Delving into biological forensic science ............................................11

Investigating the Crime Lab ..........................................................................12Creating the first crime lab ..................................................................12Identifying common procedures ........................................................13

Digging into the Criminalist’s Toolbox ........................................................14The Cornerstone of Forensics: Locard’s Exchange Principle ...................15

Looking at Locard’s principle in action .............................................15Reading the trace evidence .................................................................16Determining who did what where ......................................................16

Chapter 2: Uncovering Who Does What When: The Forensics Team in Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Gathering the Evidence: The Criminalist at Work ......................................18From Analyzing Blood to Identifying Bugs: Forensic

Science Specialists ......................................................................................19

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Forensic Investigation’s Head Honcho: The Medical Examiner ...............20Looking at two forensic systems ........................................................21Checking out the duties of a coroner or medical examiner ............22Following the medical examiner in action .........................................22

Dealing with the Dead: The Forensic Investigator .....................................23Testifying as an Expert ..................................................................................24

Understanding the court system ........................................................26Getting to the heart of the “truth” ......................................................26Understanding the role of expert testimony .....................................27

Chapter 3: Working the Scene: Evidence Collection and Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Assessing the Scene of the Crime ................................................................29Distinguishing between primary and secondary crime scenes .....30Arriving at a crime scene .....................................................................30Preserving and processing the scene ................................................31Documenting the procedure ...............................................................32Reconstructing the crime scene .........................................................34Recognizing a staged crime scene ......................................................35

Classifying the Evidence ................................................................................35Determining whether evidence is direct or circumstantial ............35Discerning physical from biological evidence ..................................36Understanding reconstructive evidence ...........................................37Identifying associative evidence .........................................................37Differentiating class and individual evidence ...................................37Analyzing the evidence ........................................................................39

Locating the Evidence ...................................................................................40Obtaining a search warrant .................................................................40Searching without a warrant ...............................................................41

Collecting and Preserving the Evidence ......................................................42Searching the area ................................................................................42Gathering the evidence ........................................................................43Packaging the evidence .......................................................................44Getting control samples .......................................................................44Keeping the chain of custody intact ..................................................45

Determining Where a Missing Corpse Ran Off To ......................................46

Chapter 4: Peering into the Criminal Mind . . . . . . . . . . . . . . . . . . . . . . .49Defining the Role of the Forensic Psychiatric Professional ......................49

Differentiating forensic from clinical psychiatry ..............................50How the mind matters in forensics ....................................................50

Testing the Brain ............................................................................................51Getting started with a medical history and physical exam ............52Digging into the psyche .......................................................................52Asking the right questions ..................................................................53Using dubious techniques ...................................................................54

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Dealing with Deception ..................................................................................54Recognizing lying perps .......................................................................55Debunking the eyewitness ...................................................................56Dealing with false confessions ............................................................56

Assessing Competence and Sanity ...............................................................58Determining a defendant’s competence ............................................58Defining insanity, loosely .....................................................................59

Tracking Serial Offenders ..............................................................................60Classifying the multiple murderer ......................................................60Making the monsters ............................................................................61

Profiling the Perpetrator ...............................................................................62Assessing the perpetrator’s psyche ...................................................64Taking trophies and souvenirs ............................................................66Distinguishing MO from signature ......................................................66Profiling the victim: Victimology ........................................................68Defining the killer’s domain .................................................................69

Linking Criminals and Crime Scenes ............................................................70

Part II: Uncovering the Evidence ..................................71

Chapter 5: Fingerprints: Your Personal Signature . . . . . . . . . . . . . . . . .73Getting a Grip on Fingerprints ......................................................................73

Measuring bodies: A precursor to fingerprinting .............................75Using ridge patterns .............................................................................77

Making Matching Easier: Classifying Prints ................................................77Grouping by arches, loops, and whorls .............................................78Developing the Henry System .............................................................79Speeding up identification: AFIS .........................................................80

Tracking Down Those Sneaky Prints ...........................................................81Looking for latent prints ......................................................................82Powdering the print .............................................................................82Using chemistry to expose prints ......................................................83Cleaning up the print: Digital techniques ..........................................84

Chapter 6: Those Messy Bloodstains . . . . . . . . . . . . . . . . . . . . . . . . . . . .85Understanding Blood’s Character ................................................................85

Thicker than water ...............................................................................85Understanding clotting ........................................................................86Oozing, gushing, and dripping ............................................................87

Analyzing Bloodstain Patterns .....................................................................87Finding clues in passive bloodstains .................................................87Analyzing projected blood spatters ...................................................89Classifying projected spatters ............................................................92Understanding transfer patterns ........................................................95Reconstructing the crime scene from bloodstains ..........................95

Putting It All Together: A Hypothetical Case ..............................................97

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Chapter 7: Making Good Impressions: Shoes, Tires, and Tools . . . . .99Stepping Out: Shoeprints as Evidence .........................................................99

Characterizing and using shoeprints ...............................................100Matching sole to soul — so to speak ...............................................101Obtaining shoe impressions ..............................................................103Making the match ...............................................................................105

Tracking Down Tires ....................................................................................105Characterizing and using tire tracks ................................................106Obtaining tire impressions ................................................................108

Getting Clues from Tool Marks ...................................................................109Characterizing and using tool marks ...............................................109Preserving tool impressions .............................................................110

Finding Facts in Fabrics ...............................................................................112

Chapter 8: The Burning Question: Is It Arson? . . . . . . . . . . . . . . . . . . .113Understanding Fire-Starters ........................................................................113Determining Where and How the Fire Started ..........................................115

Using other people’s eyes and ears ..................................................115Finding where it all started ...............................................................116Figuring out how it happened ...........................................................117Common ways to start a blaze ..........................................................117

Heating Things Up: Accelerants .................................................................118Collecting samples at the scene .......................................................118Getting answers in the lab .................................................................119Digging deeper into iffy samples ......................................................120Drawing conclusions from testing ....................................................122

Investigating Homicidal Fires ......................................................................122Location, location, location ...............................................................123Poisoned by air ...................................................................................123

Evaluating Explosive Situations .................................................................124Defining explosives .............................................................................125Investigating a bombing scene .........................................................125

Part III: Looking at the Body .....................................127

Chapter 9: Determining the Hows and Whys of Death: Forensic Autopsies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129

Defining Death and Declaring It as Such ...................................................129Looking for a definitive method ........................................................129Checking out causes and mechanisms of death .............................131Uncovering the four manners of death ............................................131

Shadowing the Forensic Pathologist ..........................................................133Discovering what makes an autopsy forensic ................................133Determining who gets autopsied ......................................................134

Performing an Autopsy ................................................................................135Identifying the body ...........................................................................135Conducting an external examination ...............................................136

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Dissecting the body ............................................................................139Looking for clues in chemicals: Toxicology ....................................140

Filing the Official Autopsy Report ..............................................................141

Chapter 10: Identifying John and Jane Doe . . . . . . . . . . . . . . . . . . . . .143Identifying the Body .....................................................................................144

Digging through the artifacts ............................................................145Using scars, birthmarks, and tattoos ...............................................145Finding evidence of wounds or disease ...........................................147Fingerprinting the dead .....................................................................147Checking out the choppers ...............................................................148

Dem Bones, Dem Bones: Working with Skeletons ....................................149Determining whether bones are human ..........................................150Determining age ..................................................................................150Estimating stature ..............................................................................151Determining sex ..................................................................................152Determining race ................................................................................153Finding individual characteristics ....................................................154Estimating time since death ..............................................................155Handling burned bones .....................................................................156Determining cause and manner of death ........................................156

Reconstructing Faces ...................................................................................157Comparing Photographs .............................................................................158

Chapter 11: Estimating the Time of Death . . . . . . . . . . . . . . . . . . . . . . .161Defining Time of Death ................................................................................161Using Changes in the Body to Estimate Time of Death ...........................162

Measuring body temperature ...........................................................162Stiffening up: Rigor mortis .................................................................163Getting the blues: Lividity .................................................................164Determining the rate of decay ..........................................................166Dealing with other possibilities ........................................................169Rising to the surface: When sinkers become floaters ....................170Looking into the eyes .........................................................................170

Using Other Clues .........................................................................................170Discovering what was on the menu .................................................171Getting buggy ......................................................................................171Checking other scene markers .........................................................172

Chapter 12: Yeow! That Hurts: Traumatic Injuries and Deaths . . . . .175Unleashing the Power of Guns and Gun Evidence ...................................175

Tracing those tricky bullets ..............................................................176Looking at entry and exit wounds ....................................................176Analyzing shotgun patterns ..............................................................178

Slicing, Dicing, and Stabbing .......................................................................178Taking the Hit: Blunt-Force Trauma ...........................................................180

Scraping and scuffing .........................................................................180Bruising and battering .......................................................................182

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Breaking bones ...................................................................................183Getting toothy: Bite marks ................................................................185Dealing with an aching head .............................................................186

A Shocking Situation: Electrocution ...........................................................190Wreaking havoc: Electricity’s path through your body .................190Assessing the damage ........................................................................191

The R Word: Dealing with Rape ..................................................................192Conducting a rape exam ....................................................................193Dealing with fatal assaults .................................................................194

Chapter 13: Asphyxia: Where’s the Oxygen? . . . . . . . . . . . . . . . . . . . .195Understanding Asphyxia .............................................................................195Gasping for Oxygen: Suffocation ................................................................196

Suffocating environments ..................................................................196Smothering ..........................................................................................196Choking sensations ............................................................................197Putting on the pressure: Mechanical asphyxia ...............................198Suffocating gases ................................................................................199

Getting a Stranglehold .................................................................................199Finding a common thread in strangulations ...................................200Hands on: Manual strangulation .......................................................200Using a ligature ...................................................................................201Hangings ..............................................................................................203

Breathing Deadly Air: Toxic Gases .............................................................204That sneaky carbon monoxide .........................................................204Deadly cyanide ....................................................................................206Getting down with sewer gas ............................................................207

Drowning: Water, Water Everywhere .........................................................207Finding the manner of death .............................................................208Digging deeper to identify drownings ..............................................208

Part IV: Working in the Crime Lab ..............................211

Chapter 14: Working with Blood and Other Bodily Fluids: Serology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .213

Becoming Bloody Knowledgeable about Life’s Most Precious Fluid .....213Understanding blood .........................................................................214Typing with the ABO system .............................................................214

Finding an Identity in a Stain ......................................................................215Knowing when blood’s really blood .................................................216Knowing when blood’s really human ...............................................218Narrowing the focus: Whose blood is it? .........................................219

Testing for Paternity ....................................................................................220Inheriting your blood type ................................................................221Determining fatherhood ....................................................................222

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Looking at Other Bodily Fluids ...................................................................222Checking for semen ............................................................................223Checking for saliva .............................................................................225Detecting vaginal fluid .......................................................................225

Chapter 15: What’s the Deal with DNA? . . . . . . . . . . . . . . . . . . . . . . . .227Opening an Instruction Manual for Your Cells .........................................227

Looking at the nuts and bolts of DNA ..............................................228Mine, mine, all mine: Uniqueness and DNA .....................................229

Fingering Criminals Using DNA Fingerprints ............................................230Tracking down and preserving DNA ................................................231Looking into the genome ...................................................................231Repeating yourself: How duplication identifies you ......................233

Understanding the DNA Fingerprinting Process ......................................234Preparing the sample .........................................................................234Making the match ...............................................................................236Indexing DNA: The CODIS System ....................................................237

All in the Family: Using DNA to Determine Lineage .................................238Who’s yer daddy? Paternity testing .................................................239Who’s yer granny? Mitochondrial DNA ...........................................240

Chapter 16: Finding Drugs and Poisons: The Toxicology Lab . . . . . .243Understanding Poisons ................................................................................243Defining Toxicology ......................................................................................244Looking for Toxins ........................................................................................245

Collecting samples .............................................................................246Determining the cause and manner of death ..................................247

Understanding the Testing Procedures .....................................................249Presuming the results ........................................................................249Confirming the results .......................................................................250Interpreting the results ......................................................................251

Looking at Common Drugs ..........................................................................253Understanding alcohol .......................................................................254Getting down with depressants ........................................................256Hopping up: Stimulants .....................................................................257Altering perception with hallucinogens ..........................................258Dirty deeds: Date-rape drugs ............................................................259Sniffing and huffing .............................................................................260Bulking up ............................................................................................261

Checking Out Familiar Poisons ...................................................................262

Chapter 17: Analyzing Trace Evidence . . . . . . . . . . . . . . . . . . . . . . . . . .265Defining Trace Evidence ..............................................................................265Understanding Analytical Instruments ......................................................266

Looking through the microscope .....................................................266Testing the chemical makeup of trace materials ............................268

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Splitting Hairs: Linking Crime to Coiffure ..................................................269Checking out hair’s anatomy .............................................................269Matching criminal to curly lock ........................................................270

Fiddling with Fibers ......................................................................................273Classifying fibers .................................................................................273Collecting fibers ..................................................................................274Comparing fibers ................................................................................274Breaking down the fiber .....................................................................275

Cracking the Mysteries of Glass .................................................................275Looking into how glass becomes evidence .....................................276Analyzing and matching glass ...........................................................276Breaking glass .....................................................................................277

Puttering with Paints ...................................................................................279Dissecting paint ..................................................................................280Solving the puzzle ...............................................................................281

Getting Down and Dirty: Soils and Plants .................................................281Identifying soils ...................................................................................281Looking at plants and seeds ..............................................................282

Chapter 18: Going Ballistic: Analyzing Firearms Evidence . . . . . . . .283Figuring Out Firearms ..................................................................................284Extracting Info from Ammo .........................................................................285

Easy does it: Handling bullets ...........................................................285Breaking down bullets .......................................................................286Determining caliber and gauge .........................................................287Shuffling through shell casings .........................................................288

Getting Groovy: Comparing Rifling Patterns .............................................288Understanding rifling .........................................................................288Reading the ridges ..............................................................................289Searching for answers in databases .................................................291

The Proof’s in the Powder: Gunshot Residues .........................................292Tracing gasses and particles .............................................................292Testing for GSR ....................................................................................293Determining distance .........................................................................294

Chapter 19: Questioning the Validity of Documents . . . . . . . . . . . . . .295Analyzing Handwriting .................................................................................296

Obtaining standards ...........................................................................297Comparing handwriting .....................................................................298Nabbing forgers ..................................................................................299

Exposing Alterations ....................................................................................300Wiping away writing ...........................................................................301Eradicating the original .....................................................................301Adding words ......................................................................................302

Looking for Indentions .................................................................................303Examining Papers and Inks .........................................................................303

Distinguishing papers ........................................................................304Identifying inks ....................................................................................305

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Dissecting Typewriters and Photocopiers ................................................306Hunting and pecking for clues ..........................................................306Finding distinctive traits in copies ...................................................307

Part V: The Part of Tens .............................................309

Chapter 20: Ten Famous Forensic Cases . . . . . . . . . . . . . . . . . . . . . . . .311Using a Homemade Ladder: The Lindbergh Kidnapping ........................311Sacco and Vanzetti and Sacco’s Gun ..........................................................313Ted Bundy’s Bite Marks ...............................................................................314Stella Nickell’s Trail of Fingerprints ...........................................................315Finding Fibers on Jeffrey MacDonald .........................................................316Georgi Markov and the Lethal Umbrella ...................................................318The Hendricks Family’s Last Meal ..............................................................318Picturing John List .......................................................................................319Being Anastasia Romanov ...........................................................................321Faking Hitler’s Diaries ..................................................................................322

Chapter 21: Ten Ways Hollywood Gets It Wrong . . . . . . . . . . . . . . . . .323The Quick Death ...........................................................................................323The Pretty Death ..........................................................................................324The Bleeding Corpse ....................................................................................324The Exact Time of Death .............................................................................325The One-Punch Knockout ...........................................................................325The Disappearing Black Eye .......................................................................326The Fast-Acting Poison ................................................................................326The Untraceable Poison ..............................................................................327The Instant Athlete .......................................................................................327The High-Tech Lab .......................................................................................328

Chapter 22: Ten Great Forensic Careers . . . . . . . . . . . . . . . . . . . . . . . .329Criminalist .....................................................................................................330Crime Scene Investigator .............................................................................330Forensic Investigator ...................................................................................331Forensic Pathologist ....................................................................................331Forensic Pathology Technician ..................................................................332Forensic Anthropologist ..............................................................................333Forensic Toxicologist ...................................................................................333Fingerprint Examiner ...................................................................................334Forensic Document Examiner .....................................................................334Forensic Medical Transcriber .....................................................................335

Index........................................................................337

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Introduction

You probably purchased Forensics For Dummies because you’re fascinatedby the marriage of criminal justice and science. I wrote this book because

I have a similar fascination. And you and I are not alone. Shows such CSI: CrimeScene Investigation, CSI: Miami, and Crossing Jordan have dominated networktelevision ratings during the past several years, attesting to the fact that mil-lions of people agree that forensics is an interesting subject. Every criminalinvestigation you see on the news or read about in the newspaper, it seems,hinges on some bit of forensic evidence.

This book is designed to give you an understanding of the techniques and pro-cedures used by forensic scientists. The next time you read or view a mysterystory or hear a news report about a crime, you can turn to this book for thescience underlying the story.

About This BookForensics For Dummies is an introduction to the field of forensic science, cov-ering a broad range of forensic topics in a clear and concise fashion. I explainthese often complex principles in plain English so that readers at all levels cangain a better understanding of forensics. The book includes many examples ofhow these techniques are applied in real-life situations. In addition, I includecase studies throughout the book to illustrate how forensic science was usedto solve famous cases.

If you know absolutely nothing about forensics, this book is an excellentstarting point. If you’re familiar with many forensic topics, this book servesto refresh and expand your knowledge.

Conventions Used in This BookThe conventional language used by scientists is foreign to most people, so Ihold scientific jargon to a minimum in this book. Still, as with other areas ofscience, the study of forensics can be dry and boring at times. To avoid paint-ing such an arid landscape, I added practical examples of how each techniqueworks, and I included many famous cases that relied on forensic science fortheir solutions. I also threw in a little humor to liven things up a bit. If myhumor falls flat, remember, I’m a physician, not a stand-up comedian.

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What You’re Not to ReadAny text preceded by a “Technical Stuff” icon (see the “Icons Used in ThisBook” section that follows) contains information for the very curious andoffers deeper, usually scientific or (of course) technical, explanations oftopics. These nuggets of information may be of interest to you, or they maynot, but rest assured that you can safely skip them and still find everythingyou need to know about forensics.

Foolish AssumptionsAs I wrote this book, I made some assumptions about you and what yourneeds may be, including that:

� You have an interest in forensics.

� You’re a fan of the many forensics shows that are aired on both networkand cable television.

� You avidly follow criminal cases reported on TV and in newspapers.

� You’re considering a career in forensic science.

� You love reading mysteries and want to better understand the sciencebehind the stories.

� You’re simply curious by nature.

How This Book Is OrganizedThe parts and chapters of this book represent a logical flow of informationabout forensic science; however, you don’t have to read them in any particu-lar order. You can pick up this book, thumb through it and read what standsout, look up specific topics in the table of contents or index, or read it coverto cover. Check out the following sections for a more detailed overview.

Part I: Cracking Open the CasePart I defines the field of forensics and looks at how the science is organized.In this section, I cover the basic principles of forensic science, define the

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roles of the medical examiner or coroner and other workers in the field, anddiscuss the legal aspects of the science. I show you how evidence is located,gathered, and preserved. I also give you a glimpse into the mindset of criminalsand how forensic psychiatric professionals and profilers help investigationsproceed.

Part II: Uncovering the EvidencePart II looks at different kinds of evidence and the ways in which these clueshelp investigators determine what happened. I include in-depth looks at finger-prints, bloodstain patterns, and the marks that tires, tools, and shoes leave atcrime scenes. I also show you how investigators get to the bottom of the par-ticularly complicated crime scenes that result when fire comes into the picture.

Part III: Looking at the BodyIn Part III, I address the many ways in which bodies provide pieces of evidence.I show you how an autopsy examination is conducted, how unkown remainsare identified, and how the very tricky matter of determining time of death isresolved. Finally, I show you how two common culprits in suspicious deaths —trauma and asphyxia — reveal themselves in a body.

Part IV: Working in the Crime LabIn Part IV, you enter the crime lab. I give you a glimpse into how crime labtechnicians uncover evidence in blood and how they use DNA to connect asuspect to a crime scene. I show you how drugs and poisons are analyzed,and how trace evidence like hair, fibers, glass, and paint tells investigatorswhat happened at the scene of the crime. I also give you the lowdown on howinvestigators find clues in bullets and how they determine whether a docu-ment was forged.

Part V: The Part of TensIn this section, you can check out ten famous cases, ten things Hollywood con-sistently gets wrong, and ten great careers for those of you who are interestedin working in the field of forensics.

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Icons Used in This BookLike other For Dummies books, this one has icons in the margins to guide youthrough the information and help you zero in on what you want to know. Thefollowing paragraphs describe the icons and what they mean.

This icon indicates that I’m giving you a look behind the scenes of a forensicpractice or area of investigation. I use it to point out in-depth discussions ofthese concepts.

I use many real-life stories to illustrate the points in this book. This icon setsoff these tales of crimes past.

Sometimes, to give you a clearer picture of how a forensic practice cameabout, I provide the historical background or a note about a related instancefrom long ago.

I flag certain pieces of information with this icon to let you know something isparticularly worth keeping in mind.

Forensics deals with plenty of mind-blowing information about such things asthe human body, evidence, and crime itself. For those of you who want justthe juicy facts, look for this icon.

This icon signals that I’m going to delve a little deeper than usual into a scien-tific or medical explanation. I don’t mean to suggest the information is too dif-ficult to understand — just a little more detailed.

Where to Go from HereForensics is a broad and diverse field that involves many areas of science andcriminal investigation. In this book, you can find out about many but not allof its concerns. You may use this book as a reference and as a springboardfor further investigation. The next time you see a news report, read a mysterynovel, or watch a movie involving a crime, you can turn to this book to obtaina better understanding of the science behind the story.

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Part ICracking Open

the Case

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In this part . . .

Solving crimes rarely involves a cape or a superpoweror even a carefully cocked fedora. Instead, it relies

upon careful observation and the tools and techniques ofscience. Criminalists start at the crime scene and followthe evidence. If all goes well, that trail leads them to theperpetrator of the crime.

In this part, I show you how forensic science works —who does what, and where and how they do it. I introduceyou to specialties in the field, to how evidence is collectedand handled (and what it is, in the first place), and to thecriminals themselves.

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