Dr. Edmond Locard, also known as the Sherlock Holmes of France, was a pioneer in forensic science. He is famous for formulating the basic principle of forensic science, known as Locard’s exchange principle: “Every contact leaves a trace.” Born on November 13, 1877, in Saint-Chamond, France, Locard pursued a career in medicine and law. He worked as an assistant to Alexandre Lacassagne, a criminologist and professor in Lyon, until 1910. During this time, Locard laid the foundation for his criminal laboratory and authored a seven-volume work called Traité de Criminalistique.
Locard, who worked as a medical examiner in World War I, utilized stains and dirt on soldier’s uniforms to determine causes and locations of death. In 1910, he persuaded the Police Department of Lyon (France) to provide him with two attic rooms and two assistants, establishing the first police laboratory. Locard was a pioneer, believing that criminals inevitably leave something behind at the crime scene while also taking something with them. Criminals can leave various types of evidence such as fingerprints, footprints, hair, skin, blood, bodily fluids, and clothing fragments. Locard put his principle into practice during investigations, such as the 1912 case of Marie Latelle’s murder. Despite her boyfriend’s alibi, Locard’s examination of the corpse revealed clear signs of strangulation. He also collected skin cell samples from underneath the boyfriend’s fingernails for analysis under a microscope.
Locard quickly discovered a pink dust while examining the samples, and he deduced that it was makeup for women. Although makeup was popular during the time of the murder, it was not widely produced. This finding prompted Locard to continue his search. Eventually, he found a chemist who had created a special powder for Latelle, confirming his suspicion. Gourbin, the culprit, admitted to the murder after deceiving his friends with a fabricated alibi by altering the clock in the game room. Locard’s exchange principle proved successful in this case. Today, this theory is still employed in crime investigations, where trace evidence must be gathered from the crime scene.
A team of police technicians, specialized in various fields, arrives at the crime scene to secure it. They document the scene, the potential victim, and collect evidence through both video recording and photography. Additionally, they may conduct firearms and ballistics analysis if required. Their tasks also include examining footwear and tire impressions, inspecting any involved vehicles, and searching for fingerprints.
