0. Fiber Analysis

1. Introduction to Fibers
Trace evidence
Class evidence
Direct transfer: suspect ←→ victim
Secondary transfer: source → suspect → victim
95% of fibers lost from crime scene within 24 hours

2. Forensic scientist determines:
Type of fiber – Natural vs Synthetic
Color
How many of each kind – Locard’s Principle

3. Forensic scientist determines:
Textile origin
Multiple types of Fibers
Transfers
Type of crime

4. Fiber Evidence Collected by: Special vacuums (large areas) Sticky tape
Forceps
Tested by:
Microscopy – polarizing light, infrared
Burn test (large quantities only)

5. Fibers are spun into yarns that have specific characteristics
Fibers may be natural or synthetic

6. Yarns are woven, with different patterns, into textiles

7. Natural Fibers Animal fibers (protein) Plant fibers (cellulose)
Sheep – wool
Goats – cashmere, mohair
Rabbits – angora
Caterpillar – silk
Plant fibers (cellulose)
Seed: cotton
Stem: hemp (Cannabis), jute, flax (linen)
Mineral fibers
Fiberglass (glass) , asbestos (rock mineral)

8. WOOL
COTTON
FIBERGLASS

9. ASBESTOS
FLAX
JUTE

10. SILK
HEMP

11. Synthetic (Man-made) Fibers
Regenerated fibers (modified natural fibers)
Rayon
Synthetic polymer fibers
Polyester
Nylon
Acrylic