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Forensic Science

Trace Evidence

Photo of Trace Evidence Microscope Exam Area

Trace Evidence Microscope Exam Area

Photo of Scanning Electron Microscope

Scanning Electron Microscope

The Trace Evidence Unit examines the largest range of evidence types and uses the widest range of analytical methods of any unit. The types of evidence examined in this unit include hair, fibers, glass, paint, soil, headlamps, shoe and tire impressions, arson debris, explosives, wood, physical matches, and gunshot residue on the hands. Materials are identified and compared with standards or known samples to determine if they share a common origin.

Examinations include:

Hairs: Suitability for DNA typing, macroscopic and microscopic comparisons of human hair.

Fibers: Identification of fiber type, identification of polymer in synthetic fibers, comparison to known samples.

Paint: Paint identification and comparison.

Shoe/tire impressions: Comparison of questioned impressions to known impressions. Tire tread patterns may be identified to a manufacturer.

Arson: Identification of flammable or ignitable liquid in liquid form or as residue in burned debris.

Explosives: Identification of chemical explosives from samples or post blast residue.

Physical matches: Absolute association between cut, broken or torn pieces of any material.

Gunshot residue on the hands: Identification of firearm discharge residue on a suspected shooter's hands.

Other materials: Identification of unknown particles using microscopical techniques and other instrumentation.