Trace Evidence

Question 1

what is trace evidence

Answer 1

Tiny fragments of physical evidence left at or exchanged from a crime scene including from a victim or suspect.

examples: hair, fibers, paint and glass

Question 2

How is trace evidence analyzed?

Answer 2

Trace evidence is typically analyzed based on its physical and chemical properties.

Question 3

Value of Trace Evidence

Answer 3

most trace evidence is unable to directly link or identify an individual or specific object.

Question 4

Value of fiber evidence

Answer 4

The rarity or commonness of the fiber determines its usefulness in an investigation.

Question 5

Class characteristics

Answer 5

• Class Characteristics are properties of physical evidence that can be associated only with a group and never with a single source. …

Examples of class evidence includeblood type, fibers, and paint to name a few.

Question 6

Individual Characteristics

Answer 6

Properties of physical evidencethat can be attributed to a common source with a high degree of certainty.

example dna toolmarks and fingerprint

Question 7

Direct Transfer

Answer 7

From victim to suspect or from suspect to victim – Ex. from suspect’s sweater to victim

Question 8

Secondary Transfer

Answer 8

• When fibers are transferred from an original source to one person and then to a second person.

Question 9

Fiber classification

Answer 9

Natural fibers are derived entirely from animal or plant sources whereas

manufactured fibers are derived from natural or synthetic polymers and number in the hundreds.

Question 10

Synthetic fibers are/can:

Answer 10

Stronger than natural fibers.

Not damaged by microorganisms.

Often cheaper than natural fibers.

destroy in bright sunlight & melt at lower temperatures.

Have very regular diameters under magnification.

Question 11

several methods used in the laboratory to identify natural and manufactured fibers

Answer 11

1. Microscopic examination
2. Dye composition analysis
3. Chemical composition