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Swedish chemist Carl Wilhelm Scheele devolved the first chemical test for arsenic, which involved changing arsenic trioxide to garlic-smelling gas using nitric acid and zinc. This was the first chemical test capable of detecting arsenic in a corpse
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A comparison of bullets was made for the first time in a criminal investigation by Henry Goddard. He found a unique defect on a bullet recovered from a crime scene that exactly matched a corresponding mark on the bullet mold from a suspect's home
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The presumptive blood test was based on the discovery by Christian Friedrich Schöbein that hemoglobin in blood causes hydrogen peroxide to foam. This was the first test for blood, which involved applying hydrogen peroxide to a stain to see if it would react and foam, indicating the likely presence of blood
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The Bertillon system was a new method of criminal identification created by Alphonse Bertillon that used a combination of detailed physical measurements and photographs to identify individuals
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The “fingerprint bureau” was not a formal, large-scale organization but the Center for Dactyloscopy, established by police officer Juan Vucethich. It was the first system for classifying and filing fingerprints for police use and was created following his development of a unique fingerprint classification system based on Galton’s work, which was used to solve the Francisca Rojas murder case
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The Uhlenhuth test, also referred to as the antigen-antibody precipitin test for species, is a test which can determine the species of a blood sample. It was invented by Paul Uhlenhuth in 1901, based on the discovery that the blood of different species had one or more characteristic proteins
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Edmond Locard founded what is considered the world’s first forensic science lab, and formulated his Exchange Principle, which states that “every contact leaves a trace.” This principle means that when a criminal commits a crime, they will always leave some trace evidence behind at the scene and will also take some evidence away with them
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Calvin Goddard advanced the system of matching bullet casings to guns, particularly with his development of the comparison microscope and its application in high-profile cases like the St. Valentine’s Day Massacre in 1929
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James Watson and Francis Crick discovered the double helix structure of DNA, proposing that it consists of two anti parallel strands twisted around each other with a specific base pairing. This discovery explained how genetic information is stored and copied
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British geneticist Sir Alex Jeffreys devolved the technique of DNA profiling, or DNA fingerprinting, using a method called Restriction Fragment Length Polymorphism (RFLP). This technique analyzes variable regions of DNA called minisatellites to create a unique pattern for each individual, similar to a fingerprint, with applications in forensics, paternity testing, and other field
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The FBI’s Computer Analysis and Response Team (CART) was established as one of the first units dedicated to handling digital evidence in criminal cases. It was created to help investigators collect and analyze data from early electronic devices like floppy disks to meet the growing challenges of cybercrime