Forensic Impression test review

Bite Mark Evidence

Impressions made by teeth on a surface

Least reliable impression evidence

Skin can stretch, changing the bite mark

Footwear Impression Evidence

Impressions left by shoes, which can be either 2D or 3D.

Tool Mark Evidence

Marks left by tools on surfaces

Class Evidence

Evidence that can only suggest a group or category, not an individual. Such as a 2D footprint

Individual Evidence

Evidence that can be linked to a specific individual.

3D Footwear Impression

• shows depth and length

• a cast can be made from this

2D Footwear Impression

• lacks depth

• footprint on a dusty floor is an example

• a cast can not be made from this

How was Ted Bundy convicted?

bite mark evidence

Striation Marks

scratches or scrapes a surface

Compression Marks

Marks made by pressing into a material, leaving an impression.

Bite mark Characterization symbol “/”

a missing tooth

Overlay

A tracing of the dentition used in comparing bite marks

Electrostatic Dust Lifter

A tool used to collect dust impressions from hard surfaces.

What’s an arrow used for with bite mark characterization?

the direction that a tooth is pointed

Location of Canine teeth

Toward the front of the mouth on either side of the front two teeth

What type of teeth are pointed and needed when comparing bite impressions?

Canines

Molar

Type of tooth located at the back of the mouth

Top teeth

Maxillary teeth

Tool mark

• leaves a striation pattern

• can be analyzed using a comparison microscope

• often found at forced entry types of crimes

Compression marks

Casting material can collect this evidence

What’s the most overlooked evidence at a crime scene?

footwear impressions

What can not be gathered from a footwear impression?

weight of the individual

Hardening spray

used to harden a 3D footwear impression

Measuring stride can…

determine the approximate height of an individual