Hair & Fibre

Regulates body temperature Acts as a sensory organ protects from the sun

Human or not If not what animal Race Potentially DNA Where on the body Toxins ingested

When it has the shaft, you can see the colour, general length, medulla pattern, pigmentation, cuticle pattern, and texture/thickness. This allows the scientists to narrow down the suspect to a group of people (curly haired, brown haired, certain pattern, etc).

Only individual when you have the root/follicle, containing the DNA.

Picking (tweezers) Vacuuming taping

Medulla pattern Cortex pigmentation Cuticle scale pattern

Thickness Texture Length Colour

Cuticle Cortex Medulla

Transparent and protective, thin outer layer. Scales always point away from the root.

Imbricate (human, dog) Coronal (bats, other rodents) Spinous (Cats)

Continuous Interrupted Fragmented Solid Absent

To find if the hair is human or animal. Animal - greater than 0.5 Human - less than 0.3 MI = width of medulla ————————– width of entire hair

Neutron Activation Analysis A nuclear process that allows scientists to determine if toxins had been ingested by an individual through their hair.

Contains pigments and makes up the bulk of the hair. May also contain ovoid bodies and cortical fusi.

May or may not be present in humans, typically always present in animals, never present in plants.

Fibres are mass produced which makes them class evidence unless they can be individualized, which is rare.

when a fibre from one persons clothing, etc directly transfers to another through contact with that person.

when a fibre is picked up from a person or the environment, left by one person and is then transferred to a third person.

Sticky lint roller Vacuuming Tweezing

Non-destructive (scanning electron microscope or light compound microscope) or Destructive (burn)

Analyzing through the lense of a microscope when you have limited evidence to work with.

Burning the fibre to see how it burns or melts, its scent, its residue, and if it must touch the flame. This is done when the is plent of evidence to use. Density tests, solvent tests, staining tests, etc may also be used.

Fibres are classified by size, starting with the smallest unit, 1 individual fibre, then yarn, multiple fibres weaved together, to textiles, multiple strands of yarn woven together.

Fibres are also classified by type, synthetic or natural. Natural fibres come from the Earth - animal, plant, or minerals. Synthetic fibres are fibres that are man-made through chemical processes. - Regenerated or polymer.