Locard’s Locard’s Exchange Exchange PrinciplePrinciple

Chapter 1 Unit #1 Notes Packet

Forensic ScienceForensic Science

The study and application of science to matters of law.

Chapter 1 Unit #1 Notes Packet

CriminalisticsCriminalistics

Criminalisticsthe scientific

examination of physical evidence for legal purposes.

Chapter 1 Unit #1 Notes Packet

Edmond Locard

Edmond Locard (1877-1966) Considered the father of

criminalistics

Built the world’s first forensic laboratory in France in 1910

Chapter 1

Locard Exchange PrincipleLocard Exchange Principle

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Whenever two objects come into contact, there is always a transfer of material. The methods of detection may not be sensitive enough to demonstrate this, or the decay rate may be so rapid that all evidence of transfer has vanished after a given time. Nonetheless, the transfer has taken place

Chapter 1

The Case of Emile Gourbin In 1912 Emile Gourbin was a bank clerk in Lyons, France. He came under

suspicion of murdering, by strangulation, his girl friend, Marie Latelle. Gourbin was arrested but produced what appeared to be an air-tight alibi. Locard went to Gourbin’s cell and removed scrapings from under his fingernails. These scrapings contained tissue that might have come from Marie’s neck, but this was not provable. Locard noticed that the tissue was coated with a pink dust, which he identified as rice starch. On the particles he found bismuth, magnesium stearate, zinc oxide, and a reddish iron oxide pigment, Venetian red. Examination of the face powder used by Marie revealed that a powder prepared for her by a Lyons druggist was similar in composition. In these days of mass-produced face powder, this evidence would have far less significance. However, in 1912, because of the special preparation, it led to the confession of Gourbin.

Unit #1 Notes Packet