Unit 2: Evidence
2.3 Class/Individual Evidence
Class vs Individual
• Physical evidence is broken into two
main categories:
• Class Evidence: characteristics common
to a group of similar objects or persons.
• Individual Evidence: can be linked to a
unique, single, specific source or person.
Purpose of class evidence
• To refine the pool of suspects.
• Size 11 shoe print found at scene.
– Guarantee suspect left print?
– Guarantee suspect has a size 11 shoe?
• No, but it does help focus the
investigation.
Class vs Individual Evidence
Which examples do you
think could be
individual evidence?
Chapter 2
Class vs Individual Evidence
 These fibers are class
evidence; there is no
way to determine if
they came from this
garment.
 The large piece of
glass fits exactly to the
bottle; it is individual
evidence.
Chapter 2
Class or Individual?
• A pistol was found in a theatre where a
man was shot. A suspect known to have
owned a Derringer like this one was
apprehended.
• Would this gun be considered individual
or class evidence?
Class or Individual?
• Can it be determined whether theses
bullets were fired from the same gun?
• How can bullets be individualized to a
gun? Explain.
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