Week 6- Photog notes
Trace Evidence
Do forensic strategy task –
Trace evidence – material found at a crime scene or accident
scene in small but measurable amount. It can link an individual
or object to the scene.
Trace evidence exhibits:
Hair, fibres, skin, glass, paint, plant material, soil, ink, liquids,
drugs, plastic, paper, fire debris, metal.
The “what, when where and how”:
Establishes charges, can help to solve hard to solve crimes,
eliminate suspects, provides timeframes (transfer and
persistence), reconstruct events and their sequence, identify
links in serial crimes and provide leads.
Commonly found evidence types:
Fibres: ant long, thin, flexible solid object with a high length it
transverse cross- section area ratio.
Hair: approx. 100 hairs are shed every day and examination of
the hair can determine the origin.
Glass: An inorganic product if fusion which has cooled to a rigid
condition without crystalizing.
Paint: A manufactured liquid that dries to form a thin, hard
coating.
Factors affecting primary transfer:
Distribution, hot the contact accrued, shed ability, time of
contact, amount of contact, area of contact, type of fabric,
force used during contact.
Factors affecting secondary transfer:
, ^ same + persistence of fibre types, redistribution of fibres,
activity since primary transfer.
Retention factors`.
WATT
Washing, activity, time, texture
Fibre: any substance which has a high length to transverse
cross-sectional area ration. Flexible in nature. Can be spun
int0n a yarn.
Yarn: A term for a continuous strand found from a group of
natural/synthetic fibres twisted or laid together for use in
weaving/knitting.
Staple: length of fibres naturally found in cotton and wool.
Filament: A long continuous fibre. Doesn’t require spinning to
form a yarn.
Examples of fibres:
• Viscose
• Polyamide (nylon)
• Acetate
• Rayon
• Acrylic
• Polyester
• Elastane
• Asbestos
• Wool
• Angora
• Cashmere
• Silk
• Cotton
• Bamboo
• Jute
• Hemp
• Flax
Potential sources of fibres:
Strands of hair
Trace Evidence
Do forensic strategy task –
Trace evidence – material found at a crime scene or accident
scene in small but measurable amount. It can link an individual
or object to the scene.
Trace evidence exhibits:
Hair, fibres, skin, glass, paint, plant material, soil, ink, liquids,
drugs, plastic, paper, fire debris, metal.
The “what, when where and how”:
Establishes charges, can help to solve hard to solve crimes,
eliminate suspects, provides timeframes (transfer and
persistence), reconstruct events and their sequence, identify
links in serial crimes and provide leads.
Commonly found evidence types:
Fibres: ant long, thin, flexible solid object with a high length it
transverse cross- section area ratio.
Hair: approx. 100 hairs are shed every day and examination of
the hair can determine the origin.
Glass: An inorganic product if fusion which has cooled to a rigid
condition without crystalizing.
Paint: A manufactured liquid that dries to form a thin, hard
coating.
Factors affecting primary transfer:
Distribution, hot the contact accrued, shed ability, time of
contact, amount of contact, area of contact, type of fabric,
force used during contact.
Factors affecting secondary transfer:
, ^ same + persistence of fibre types, redistribution of fibres,
activity since primary transfer.
Retention factors`.
WATT
Washing, activity, time, texture
Fibre: any substance which has a high length to transverse
cross-sectional area ration. Flexible in nature. Can be spun
int0n a yarn.
Yarn: A term for a continuous strand found from a group of
natural/synthetic fibres twisted or laid together for use in
weaving/knitting.
Staple: length of fibres naturally found in cotton and wool.
Filament: A long continuous fibre. Doesn’t require spinning to
form a yarn.
Examples of fibres:
• Viscose
• Polyamide (nylon)
• Acetate
• Rayon
• Acrylic
• Polyester
• Elastane
• Asbestos
• Wool
• Angora
• Cashmere
• Silk
• Cotton
• Bamboo
• Jute
• Hemp
• Flax
Potential sources of fibres:
Strands of hair
