1. An Introduction to Evidence
Notes 1.2
An Introduction to Evidence

2. Evidence….
can help determine if a crime has occurred (recall Locard’s Exchange Principle)
can help to reconstruct a crime scene
can link individuals to a crime scene
Can link individuals to each other
Basically two types: Circumstantial and Direct

3. Common Types of Evidence (x4)
Circumstantial Evidence (1/4)
Circumstantial evidence is a series of facts that can be used to infer another fact.
suspect found with a large amount of money without being able to give any reason

4. Common Types of Evidence
Direct Evidence (2/4)
Evidence that stands on its own to demonstrate an alleged fact.
Direct “proof” of a fact without inference.
testimony by a completely credible witness about what he/she personally saw, heard or did

5. Common Types of Evidence (Can be Either Direct or circumstantial)
Physical Evidence (3/4)
Physical objects that are linked to the commission of a crime
Hair
Fingerprints
Fibers
DNA
Recordings
Blood, Semen, Saliva
Documents
Drugs
Explosives
Firearms/ammunition
Glass
Impressions
Tissues/Organs
Paint
Petroleum Products
Plastic Bags
Powder residue
Serial numbers
Wood and Vegetable Matter

6. Common Types of Evidence
Testimonial Evidence (is direct evidence) (4/4)
Given by a lay or expert witness
The Credibility of the person is extremely important
DNA expert
Blood spatter expert
Ballistics expert
Witness to the crime

7. the crime scene, the victim,
Linkage Triangle
The linkage triangle shows the relationship and movement of materials among
the crime scene, the victim,
and the suspect.

8. Linkage Triangle: Close it and solve the crime!
Victim
Suspect
Crime Scene