The History of Forensic Science

One of the first instances of a forensic investigation can be found in an anecdote from ancient China. After a peasant had been murdered, the village lawman used the slash wounds on the victim's body to narrow down the culprit. He summoned together the three farmers who worked the fields closest to the scene of the crime and had them place their scythes on the ground before them. As the lawman questioned them over the course of several hours, flies began to collect on one particular scythe. While the scythe had been wiped clean, there were traces of blood left behind that attracted the insects.

Although this story wouldn't hold up as hard evidence in a court of law today, the foundation of this story is what lies at the center of many modern forensic practices.

Fingerprints were recognized as unique to individuals back in 200 BC, and used as a means to sign contracts among Babylonians. China used fingerprinting in criminal investigations around the same time, during the period of the Qin Dynasty. This practice wouldn't reach the West for a very long time. 

In 1892, English polymath Sir Francis Galton at last saw to it that fingerprints were the popularized method of classification in investigations. After compiling research on how likely it would be for two different people to have a matching set of fingerprints, Galton then went about dividing fingerprint shapes into broad categories. Those categories—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—are the same ones we use today.

Unfortunately, Galton, while a genius across many subjects, is a controversial figure for many reasons. Among them is the fact that he was the inventor of eugenics, the main factor in the justification of genocide across the world. And probing deeper into his popularization of fingerprints, one will find that the idea was blatantly stolen from other researchers of the time.

Dr. Henry Faults published an article in 1880—12 years prior to Galton's popularization—that predicted the usefulness of fingerprints in criminal investigations. Faulds borrowed from the ideas of Sir William James Herschel, who has been utilizing fingerprints in India as a way to combat signature forgeries. He drew too on his own experiences with law enforcement in Japan and sought out Charles Darwin (Galton's half-cousin) to help him move forward in his research. It was then that Darwin passed on Faulds' research to Galton.

In the late 18th and early 19th century, Eugene Vidocq was a clever criminal operating in France. However, by 1811, Vidocq gave up his life of crime and founded the Brigade de la Sûreté, a plainclothes investigative unit. Using his perspective as a former criminal, this criminologist founded the vital ideas of ballistics analysis, undercover investigations, and footprint analysis.

Vidocq also advocated for the first major criminal database, theorizing that most crimes were perpetrated by re-offenders. Vidocq himself had a photographic memory, but for those of his colleagues that didn't have the same gift, it was helpful to have a compilation of data to compare evidence to. Following an arrest, the police would record a suspect's aliases, physical description, former convictions, possible motive, and any other relevant piece of information. As time passed, these records grew only more detailed, and today that very system is in use in digital form.

Edmond Locard made great strides in modern forensic science in the early 20th century. Called the French Sherlock Holmes, Locard drew from the world of fiction to combat the struggles of unreliable eyewitness testimony and wrongfully obtained confessions. He turned to the very deductive logic that Sir Arthur Conan Doyle wrote about, and used his experience as a medical examiner in World War I to bring about the popularity of trace evidence.

In 1910, Locard rented a two-room attic in Lyon and turned it into the world's first crime lab. It wasn't until two years later that he broke his first major case. A woman had been murdered in her parent's house, but the prime suspect—her boyfriend—had an airtight alibi. Examining the corpse, Locard was able to determine that strangulation was the cause of death. Upon scraping under the boyfriend's fingernails, he discovered a pink residue he was able to identify as women's makeup. This precise makeup wasn't mass-produced, and was able to be traced back to a specific vendor. From there, Locard matched the fingernail residue to the beauty shop of the murder victim, leading to the boyfriend's arrest. His confession revealed that the men who vouched for his alibi were deceived by an improperly set clock.

Locard is most famous for coining the exchange principle, which states that whenever there is contact between two items, there will be an exchange of material. This relates to fingerprints, blood, hair, clothing fibers, and other forms of trace evidence.

But the biggest shift in forensic science came with the ability to more thoroughly examine this trace evidence. In the mid-1980s, crime labs saw the development of DNA matching.

In 1984, British geneticist Sir Alec Jeffreys discovered that DNA showed both similarities and differences among family members, making it possibly the most precise form of identification to be found. Over the course of the next three years, Jeffreys' lab was the only one with the capability to perform this DNA testing, overwhelming it with investigative requests.

Jeffreys' method was first used in a criminal case in 1986, during the investigation of the rape and murder of two women. Samples of blood and saliva were taken from over 4,00 local men, and only one match returned. The criminal—Colin Pitchfork—was arrested, and the former suspect, Richard Buckland, was fully exonerated after a false confession.

With the rise of computers, cell phones, and video technology, the past couple of decades have seen big changes in forensic science. For one thing, we've seen the implementation of CODIS (Combined DNA Index System), the FBI's DNA profile database, and NDIS (National DNA Index System), the combined profiles obtained at a federal, state, and local level.  This has helped apprehend criminals who operate on a national level.

In addition to improvements in database management and sharing, the authorities have also implemented location tracking using GPS software and cellphone towers. This mapping technology exists across multiple electronic devices, and records data even when no applications are in use. That means cars, phones, and even watches can be the downfall of criminals.

One of the latest tools in digital forensics is facial recognition software. This can scan faces in CCTV footage or still pictures to pinpoint if any people of interest were present at the time of a crime. Controversially, this can also lead to the identification of people of interest before a crime even takes place.

As the world's digital technology continues to rapidly evolve, so too will the advancements of forensic science. However, forensic science will also continue to run into controversies surrounding the implementation of these advancements. Where does protection violate privacy in the eyes of surveillance? How do internal biases and systemic injustices play a role in the gathering of trace evidence? And how can we treat forensics as certainties when all science is prone to error?

Only the passage of time will tell how forensic evidence will continue to change, but the exploration of the limitations of forensics is not hobbling the science. In fact, the more that the science is called into question, the more great minds come together to find even better solutions.

Featured image: Immo Wegmann/Unsplash; Other images: Immo Wegmann/Unsplash; Julia Koblitz/Unsplash