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.

Chapter 2

Class vs Individual Evidence

Which examples do you think could be individual evidence?

Chapter 2

Class vs Individual Evidence

The large piece of glass fits exactly to the bottle; it is individual evidence.

These fibers are class evidence; there is no way to determine if they came from this garment.

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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