1.6: Edmond Locard

Figure \(\PageIndex{1}\): Edmond Locard - Permission granted for publication: 99PH, fonds Denise Locard Stagnara, Archives municipales de Lyon.

It is your author’s humble opinion that the person who had the most influence on the forensic sciences was Edmond Locard, so much so that in his lifetime he was called “The Sherlock Holmes of France.” Dr. Locard studied both medicine and law and had a keen interest in combining medical science with legal matters. He studied under Dr. Alexandre Lacassagne, the French criminologist who founded the Lyon-based Lacassagne School of Criminology, and who famously wrote, “Every society gets the kind of criminal it deserves.” In 1910, Dr. Locard approached the administration of the Lyon Police Department and offered his services as a criminalist for their forensic laboratory. The only problem was that they did not have one; no one did. He was able to convince the police officials to allow him to fund and operate a laboratory, likely modeled after the fictional laboratory found at 224B Baker Street, in two small rooms in the attic of the police station. The laboratory was officially recognized by the Lyon Police Department in 1912. This laboratory was the first known criminalistic laboratory in the world. It did not take Dr. Locard much time to put his forensic talents to work. In 1912, Dr. Locard was called to the murder scene of Marie Latelle, who was found shortly after midnight in a room of her parent’s house. Her boyfriend, Emile Gourbin, was suspected of the murder by the Lyons Police Department. There was just one problem, Emile was playing cards with friends at his apartment when the crime was believed to have occurred. Dr. Locard was asked to make an examination of Emile, and with magnifying glass in hand, Dr. Locard discovered the residue of a reddish-pink powder underneath his fingernails. Dr. Locard collected this powder by scraping the fingernails into a pharmaceutical fold envelope. He then went to the crime scene. He noticed a jar containing a face powder that was sitting on the vanity of the victim, which he collected into evidence. He also noted the victim had bruising consistent with fingermarks on her neck. In the laboratory, Locard identified the components of the powder from the fingernail scrapings as bismuth, zinc oxide, magnesium stearate, and Venetian red, a reddish iron oxide pigment. The same components were found in the face powder he collected from the crime scene. He later discovered that the powder was sold to Marie Latelle by a Lyons druggist who made the formula specially for her. Faced with this information, Emile confessed to the crime. In order to have an alibi, he invited his friends to his house for a card game. Prior to their arrival, he set the clocks in the apartment back one hour. He insisted his friends leave the apartment at midnight, making it a point that they look at the clock to mark the time; however, it was only eleven. That is when he snuck out of the apartment from an upstairs window, climbed through the window of Marie’s bedroom, and strangled her to death. In 1920, Dr. Locard published his theory of evidence exchange in which he surmised that when two objects come into contact with each other, a transfer of evidence will occur between the two objects. This is the primary theory associated with the forensic principles of trace and transfer. Your author believes the more violent the contact, the more likely evidence will be transferred from the suspect to the victim, the victim to suspect, and the suspect and victim to the crime scene. In the 1960’s, the American criminalist Dr. Paul Kirk summed up Locard’s Principle of Evidence Exchange as follows:

“Wherever he steps, wherever he touches, whatever he leaves, even without consciousness, will serve as a silent witness against him. Not only his fingerprints or his footprints, but his hair, the fibers from his clothes, the glass he breaks, the tool mark he leaves, the paint he scratches, the blood he deposits or collects. All of these and more, bear mute witness against him. ‘This is evidence that does not forget. It is not confused by the excitement of the moment. It is not absent because human witnesses are. It is factual evidence. Physical evidence cannot be wrong, it cannot perjure itself, it cannot be wholly absent. Only human failure to find it, study and understand it, can diminish its value.”

Just imagine that this concept was understood before the advent of deoxyribonucleic acid typing in criminal investigations.

Your author recommends a glance at the seven-volume Traité de Criminalistique (Treaty of Criminalistics) to see even more contributions Dr. Locard gave to the forensic sciences.