A Quick History of Forensic Science: Fingerprints, DNA & Beyond

Anecdotal stories of the birth of forensic investigations reach back thousands of years. One such tale begins with a peasant having been slashed to death in ancient China. The village lawman then gathers the three farmers who work the fields closest to the crime and has them lay their scythes out on the ground. As the lawman questions them over many hours, flies begin to collect around one scythe in particular; though washed clean, the traces of blood on the scythe are still detectable by these deputized insects. While that story itself might not be admissible in one of today’s courtrooms, the logic underpinning its narrative is still used in contemporary forensic practice.

Forensics is a broad field, pulling from several different scientific disciplines. Archimedes’ bathtub discovery of how to measure volume (Eureka!) had immediate applications in detecting forgeries of gold.

In 200 BC, the Babylonians used fingerprints to sign contracts, but the practice of fingerprinting wouldn’t see use in Western investigations until thousands of years later. In China, they were used in this manner as early as the Qin Dynasty. In 1248, Song Ci wrote Washing Away of Wrongs, introducing regulations for autopsy reports in Chinese courts, and also relating the ancient story of the scythe and the flies, among other colorfully instructive lessons.

Forensics is an exciting field no matter the era in which it’s practiced; there’s always a little more than meets the eye. To get a quick look at the history of forensics and the crimes it solved as well as committed, read on.

Fingerprints: Nice Idea, Mind If I Steal It?

In 1892, Sir Francis Galton popularized a method for classifying fingerprints, one that is still used today. After he conducted statistical research into the likelihood of two people having the same sets of fingerprints, Galton set about categorizing different types of fingerprint patterns into broad classifications: the plain arch; the tented arch; the simple loop; the central pocket loop; the double loop; the lateral pocket loop; the plain whorl; and the accidental. Galton also helped build the scientific foundation for studies that would back up his system, helping it to gain traction in the courts.

A half-cousin of Charles Darwin, Galton was a veritable Renaissance man; an incomplete list of his professional titles includes those of geographer, explorer, inventor, psychologist, and statistician. Sadly, Galton was also the inventor of eugenics, a pseudoscience whose most impactful contribution to the world has been the justification of genocide. A further investigation of Galton’s past finds that Galton was unscrupulous in other areas, too: he’d stolen the fingerprinting idea from other researchers.

Over a decade earlier, in 1880, Dr. Henry Faulds published an article in Nature that predicted the forensic usefulness of fingerprinting. Borrowing from the work of Sir William James Herschel, who had been using fingerprinting in India as a way to battle signature forgery, Faulds added his own experiences with law enforcement in Japan, proposing fingerprinting as a serious investigative tool. Dr. Faulds then sought out Charles Darwin to help further the research. Darwin passed on Faulds’ findings to his half-cousin, Galton. While Galton did indeed popularize the first method of modern fingerprint classification a few years later, he never credited Faulds or Herschel for their work, and a feud ensued between the three men for decades.

Databases: To Catch a Thief, Think Like a Thief

Meet Eugene Vidocq, a career criminal turned professional criminologist who operated in early 19th century France. His life story influenced major writers like Edgar Allan Poe and Victor Hugo, but his life’s work had an enormous impact on the forensic sciences.

In 1811, having sworn off the life of crime, Vidocq founded a plainclothes investigative unit called the Brigade de la Sûreté, and by 1813, he had Napoleon’s blessing. Using his own perspective as a former criminal, Vidocq introduced the world to the concepts of ballistics analysis, undercover investigations, and footprint analysis.

Vidocq also championed the first major criminal database, which he based on his theory that many crimes were committed by re-offenders (such as himself!). While Vidocq was said to have a photographic memory, he knew he couldn’t rely on his colleagues to have the same, so he implemented a system of anthropometrics that’s still partially in use by French police today. After each arrest, officers would record the suspect’s aliases, physical description, previous convictions, likely motive, and other relevant information, such as handwriting samples for suspected forgers.

Over time, the information got more and more detailed, and the system got more developed (thanks, in part, to another French police officer, Alphonse Bertillon). These types of databases still exist to this day, in digital form.

Crime Labs: Life Imitates Art

In the early 20th century, Edmond Locard became known as the French Sherlock Holmes, and he’s now credited as one of the fathers of modern forensic science. While the Sherlock Holmes stories of the late 19th century focused on the nature of evidence and the power of deductive logic, investigations in the real world at that time largely centered around fallible eyewitness testimony and corruptly extracted confessions.

Locard borrowed from the world of fiction, and from his own experience as a medical examiner in World War I, to bring forensic science—particularly the notion of trace evidence—into modern usage. In 1910, Locard rented a two-room attic in Lyon and transformed it into what’s considered the first forensic crime lab.

It wasn’t until 1912 that Locard and the lab broke a major case. A woman was found murdered in her parents’ house and the prime suspect, her boyfriend, had a solid alibi by contemporary standards: four men swore that they had been playing cards with the boyfriend at the time of the murder.

Locard analyzed the corpse and determined the cause of death to be strangulation. He then scraped under the boyfriend’s fingernails and found a pink residue, which he identified to be women’s makeup. Makeup wasn’t mass-produced at the time, and could therefore be traced back to its vendor with certainty. Locard matched the fingernail residue to the victim’s beauty shop and the boyfriend was arrested; in his confession, he revealed that he had set the clock back an hour at the card game where the others had vouched for his presence.

Locard is famous for his exchange principle, which states that whenever there is contact between two items, there will be an exchange of material. That principle now forms the basis for much of forensic science, taking into account fingerprints, blood samples, hair analysis, and other forms of trace evidence.

Forensic Education: Practice Makes Perfect

Frances Glessner Lee, America’s first female police captain, is often referred to as the mother of forensic science, and she played a critical role in the field’s development in the United States.

Through her own personal advocacy, she successfully lobbied to have coroners replaced with medical professionals, thereby professionalizing the field of forensic pathology. In 1931, Lee also used her own money to help start Harvard University’s Department of Legal Medicine—the first of its kind in the country—and she eventually went on to found the Harvard Associates in Police Science, a national organization dedicated to furthering the field of forensic science. Prior to this, very little training existed for forensic investigation.

One of Lee’s enduring legacies is a series of crime scene dioramas titled The Nutshell Studies of Unexplained Death, which she began constructing in the 1940s. A set of meticulously crafted crime scenes in miniature, these 20 dioramas were modeled after real and challenging cases and designed to test the abilities of forensic students to properly collect and analyze all the relevant evidence. Common themes within the cases include an increased focus on “invisible victims” from society’s lower classes and the danger of unconscious biases in forensic investigations.

Lee’s murderous arts-and-crafts have been exhibited in major art galleries, such as the Renwick Gallery of the Smithsonian American Art Museum, as recently as 2018. Today, 18 of the 20 dioramas are still used to train investigators by Harvard Associates in Police Science.

DNA: Forensic Science Investigates Itself

The mid-1980s brought about perhaps the biggest leap forward for forensic science since the analog fingerprint: DNA matching.

In 1984, Sir Alec Jeffreys, a British geneticist, stumbled across the realization that DNA showed both similarities and differences between family members, making it perhaps the most accurate form of identification ever discovered. For the next three years, Jeffreys’ laboratory was the only one in the world capable of performing DNA matching and it received an enormous number of requests in that timeframe.

In 1986, Jeffreys’ method was employed in a criminal case for the first time, when local police were investigating the rape and murder of two women: one that occurred in 1983, and one that occurred in 1986. Blood and saliva samples were collected from more than 4,000 men in the area, but the method identified only one match for both crime scenes: the DNA of Colin Pitchfork. Without the use of DNA matching, Pitchfork would never have been apprehended. But just as importantly, it exonerated Richard Buckland, a man who had been up until then the prime suspect (having falsely confessed) and whom authorities say would have served life in prison if not for Jeffreys’ contributions to the case.

Today, DNA alone is not enough to secure a conviction, but it still plays a significant role in forensic investigations. And, similar to that first case in 1986, it’s proven to be as powerful a tool for determining innocence as finding guilt. In 1989, Gary Dotson was exonerated after ten years in jail thanks to DNA evidence. There have been 375 more DNA exonerations since. In modern investigations, thousands of cases have seen prime suspects identified and pursued only to be found innocent prior to conviction thanks to Jeffreys’ discovery.

The Future History of Forensics

The evolution of forensics is far from finished. Today’s forensic investigators are continuing to write the future’s history with advancements in digital forensics. And the trend of controversy is sure to continue: today’s forensic scientists are looking inward at their own internal biases, at systemic injustices, and at the legal gray areas of privacy.

Previously proven truths such as fingerprint identification and DNA matching are coming under harsh scrutiny. But a willingness to seek out errors and admit them isn’t a sign of weakness—it’s a strength—and it’s one that forms a core principle of forensic investigation.