1. Fibers
Notes on Page 24-25

2. What information can fibers give us?
Type of fiber
Color of fiber
Number of fibers
Where was the fiber found?
Textile of fabric (upholstery from car, carpet fibers?)
Multiple fiber transfers
Time between crime and discovery of fiber
Type of fiber – what is the composition of the fiber? Is it common or rare? What suspects, victims or part of the crime scene had this type of fiber on them?
Number of fibers could suggest more violence or longer period of contact
Location of fiber could tell investigators how close the suspect was to the crime scene, to the victim

3. How are fibers left or picked up at a crime scene?
Direct transfer – fibers originating from carpets, clothing, linens, furniture or ropes can be transferred directly from suspect to victim, victim to suspect or crime scene to suspect
Example – Jeffrey Macdonald case study
Fibers from his blue pajamas were found on the body of his wife

4. How are fibers left or picked up at a crime scene?
Secondary transfer – victim has picked up fibers from another source and then transferred fibers to suspect (or from original source to suspect to victim)
Example: Wayne Williams case study
Fibers from his carpet were transferred to him and then transferred to victims’ bodies

5. Fiber collection
Only collect fibers you wouldn’t expect to see at the crime scene
If the victim had wall-to-wall orange carpeting and there was an orange fiber on the body, you wouldn’t examine that fiber
Use special vacuum, sticky tape or tweezers to collect fibers
Package in separate coin envelopes or paper bindles; label
Be sure to collect control samples from victim’s house, clothing, crime scene and suspect!!!

6. Characteristics for Comparison of Fibers
Appearance and type
Feel
Weave pattern
Thread count
Infrared spectrophotometry – the wavelengths of light that the fiber absorbs
Fiber burn test

7. Types of Fibers - Natural
Natural fibers come from animals, plants and minerals that are mined from the ground
Examples:
Animal fibers: wool, cashmere, mohair, angora, silk
Plant fibers: cotton, linen, ropes, twine
Mineral fibers: asbestos
Mohair sweater
Asbestos insulation

8. Types of Fibers - Synthetic
Man-made fabrics
Examples:
Rayon, acetate, nylon, polyester
Can be mixed with a natural fiber
Example: carpet
Polyester jacket
Carpet – made from plant material and acetate

9. Weave Patterns Plain Weave Twill Weave Basket Weave
Single strands that alternate over and under
Single strand goes over three strands and under one
Double strands that alternate over and under