History of forensics
Forensics investigation relies on one basic principal - that every contact leaves a trace.
This was a discovery made by Edmund Locard - the head of the world’s first crime investigation laboratory based in Lyon, France.
Locard’s principal of exchange, states that if there is contact between two objects there will be an exchange so the criminal will leave something at the scene of the crime, fingerprints, hair, fibres, saliva etc and they will take something away from the crime scene.
The principal has remained unchanged for 100 years.
Locard’s influence in the forensic world remains as strong today as it did in 1910 when the lab was first opened. Many forensic companies incorporate Locard’s name within their organisation in acknowledgement of the contribution he made.
Police officers are trained to apply this principal at every stage during the investigation of crime.
Their are various types of forensic evidence, including:
Fingerprints
DNA
Footprints
Fluids & Residues
Paint
Glass
Fibres
Forensic evidence can be gathered from:
Blood
Cigarette butts
Discarded wallets / handbags
Blobs of spittle
Chewing gum
Victim swabs - bitten, kissed, struggled
Fingernails / Toenails
Combs, Razors, Toothbrush
Cigarette lighters
Used clothing, underwear, watch straps and many more




