Case Analysis

Forensic Science 101: Introduction

Has anyone ever wondered how Dana Scully uses science to help with her deductions? It’s more than just simple observation, it is a very involved process. Contributor Mimic has written a series of articles about the fascinating subject of Forensic Sciences, this is the first of the multiple part series.

Article by Mimic.
Page editor: XScribe.

Definition: fo-ren' sic (fə-ren' sik) adj. relating to the application of science to decide questions arising from crime or litigation.

Most of modern society is familiar with the term "forensics," thanks to news articles about serial murders and television programs like Forensic Files, CSI, and The X-Files. But there's a lot more to forensic science than just crime scene investigation and profiling. For one thing, the word "forensics" is derived from the Latin forensis, meaning "of or before the forum" and was originally (and correctly) used when arguing legal matters in a judicial setting.1 Thus the subject we wish to discuss here is more correctly called "forensic science" -- the multitude of scientific methods used in the investigation of crime. But what are the various branches of forensic science? How did the modern forensic disciplines develop? What purposes do they serve and how are they carried out? While it won't be possible to look in-depth at every forensic discipline, this series of articles will attempt to provide an overview of the most common and still touch on the not-so-common branches with which people might not be as familiar. Hopefully, the reader will come away with a better understanding of exactly what constitutes forensic science and why some of its many discoveries have been considered the seminal scientific contributions of their day.

But first, a short history lesson.

As we all move through our lives, it is inevitable that "with contact between two items, there will be an exchange." In other words, we leave little traces of ourselves everywhere we go (hair, fibers, bodily fluids) and take away little bits of where we've been (soil, rocks, vegetation). Edmond Locard made the above observation in 1910, but since then, his words have been condensed into the Locard Exchange Principle, which is the core of criminal investigation -- "every contact leaves a trace."2 From fingerprints to entomology, trace evidence to DNA, forensic scientists have been taking advantage of this fact for centuries.

One of the first systematized methods of identification was developed in the 1880s by a French police clerk named Alphonse Bertillon. Faced with huge numbers of files which needed to be organized, he adapted a system of measurements used by physical anthropologists and created an identification method that relied on specific bodily measurements and physical characteristics of perpetrators, recorded on a card in the file. Eventually, he included a photograph of the individual as well. Christened Bertillonage, his system was used to identify criminals for two decades before being eclipsed by the advent of standardized fingerprint analysis, yet anyone familiar with a routine police file will still see remnants of Bertillon's innovation in the information and photographs contained therein.3

Although Bertillon's era is often hailed as the beginning of modern investigative forensic science, he was preceded by centuries full of scientific discovery. In 250 AD, the Greek physician Erasistratus noticed that the pulse rate of his patients increased when they lied; the first lie detector test. In a trial sometime between 1000 and 1100, Roman attorney Quintilian proved that bloody palm prints found at the scene of a woman's death were planted to frame the victim's blind son. The first official guide for coroners was introduced in China in 1248 when the book Hsi Duan Yu (The Washing Away of Wrong) described how to tell death by drowning from strangulation. In 1658, English physician, Sir Thomas Brown, documented his findings on adipocere, the waxy, fatty substance which indicates that a corpse has been interred in cold, wet soil--a significant observation for dating time of death. In the 1780s, John Toms of the UK was convicted of murder when a piece of paper in his pocket matched the wadding in a pistol used to commit the killing. One of Scotland Yard's original Bow Street Runners, Henry Goddard, used bullet comparison to catch a murderer in 1835. The first experiments to determine time of death from body temperature were carried out on dead soldiers in Malta and Britain around 1839. Discoveries continued at an increased pace over the next fifty years, including the first tests to detect arsenic in body tissues (1840 France), the first presumptive tests to detect blood traces (1863 Germany), the classification of fingerprints for identification purposes (1870s Britain), and the first mechanical lie detector test utilizing changes in blood volume (1880 Italy).4

So what, exactly, IS the criminal (rather than legal) branch of forensics? It is the study of fingerprints, handwriting, bite marks, voice prints, psychological make-up, and DNA profiles to identify perpetrators. It is the examination of insects, soil, pollen, toxins, micro-organisms, and decomposition that help to indicate the time, place, and cause of death. It is piecing together bone fragments, bullet trajectories, blood spatter patterns, footwear and tire impressions, and digital information to give law enforcement the big picture. The science behind some of these disciplines has been with us for centuries, while other areas are so new that their ultimate potential is still unknown, which begs the question: what next? Since we can't see into the future to provide an answer, let us instead look to the past for an understanding of all the elements which make up the science of forensic investigation.

Editor's Notes
1 Merriam-Webster Dictionary
2 Evans, Colin. The Casebook of Forensic Detection. John Wiley & Sons, NY: 1996. Print.
3 The Journal of Behavioral Profiling. All information in this paragraph is condensed from this site.
4 Crimeline: History of Forensic Science. All information in this paragraph is condensed from this site.
Additional information was obtained from and then researched on other web sites for reliability.