Classifying Evidence

Forensic Notes

Dr. Edmond Locard

-known as the father of forensics

-established the first forensics laboratory in Lyon France in 1910

- known for Locard’s Exchange principal

Locard’s Exchange Principal

states when a person comes into contact with an object (or another person), a cross-transfer (excahnge) of physical evidence can occur

• the exchanged materials indicate that the two entities were in contact

• The intensity, duration, and nature of the entities in contact determine the extent of transfer

• Forensics is built upon this principle

• Evidence solves crimes

• This evidence bears a silent witness to the criminal act

Direct Evidence

includes firsthand observations

• eyewitness accounts

• police dashboard

• video surveilance

• Voice recordings

• Signed ransom notes

• Reports (toxicology, lab, etc.)

Circumstanitial Evidence

Indirect evidence that can be used to IMPLY a fact but not directly prove it

• Prints

• DNA

• Ballistic evidence

• Fibers

• Hair

-Physical or Biological

Circumstanitial Physical

• All prints

• Bullets

• Weapons

• Synthetic fibers-plastics

Circumstanitial Biological

comes from living things

• DNA

• Hair

• Natural Fibers-cotton

Class

narrows to a group of people/items

• shoe prints

• blood type

• hair(w/o follicle)

Individual

narrows to one individual

• DNA

• Hair (w follicle)

• Fingerprints