FSC239Y5 Lecture Notes - Lecture 25: Punched Pocket, Stereo Microscope, Trace Evidence
FSC239 Lecture 25: Hairs and Fibers
• History of trace evidence
o The microscopic debris that covers our bodies are the mute witnesses sure
and faithful, of all our movements and all our encounters. Every contact
leaves a trace
o Fibers and hairs can be transferred between individuals, between individuals
and objects, or between objects
• Purpose
o Investigative
▪ Holly Jones case
▪ Hairs for nDNA analysis
o Associative
▪ Established contact between objects/persons/scenes
• Transfer and persistence
o Approx 80% of hair and fibres are lost in the first 4hours from
contact/transfer
o Factors affecting rate of loss
▪ Type of donor/recipient textiles
▪ Length of hair/fibre
▪ Environmental conditions
▪ Handling/Cleaning
• Collection
o Objectives
▪ Efficient collection of evidential extraneous hairs and fibres
▪ Prevention of contamination between items or environment
▪ Proper storage of evidence for later
o Methods
▪ Taping (goes over surface of the object to collect fibres. Item is laid flat
on table as clear tape is used to go over the fabric. They are then put
on sheet protector.)
▪ Picking by eye or under a stereomicroscope
• Proper handling of evidence
o Case items are segregated into groups which originate from a common source
o A sequence is chosen for taping items from different sources so that potential
contamination is minimized
o Items from different sources are taped in different H&F taping
o A different lab coat is worn for taping items rom different sources
o Work area is cleaning before and after taping and mounting
o Examiner’s clothes are taped for control purposes
• Hair evidence
o Objectives
▪ Identification
▪ Method of removal
▪ Suitability for nuclear DNA analysis
▪ Chemical/physical treatment/damage
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