FSC239Y5 Lecture Notes - Lecture 27: Polarized Light Microscopy, Fourier-Transform Infrared Spectroscopy, Stereo Microscope
Document Summary
Holly jones case: no leads, then found many green fibres. Found that suspect recently changed bathroom mat, but the whole bathroom was green and the new mat was black. Based on ed(cid:373)o(cid:374)d locard"s pri(cid:374)ciple: ever(cid:455) co(cid:374)tact leaves a trace. Fibres and hairs can be transferred between individuals or objects (physical contact) 80% of hairs/fibres are lost in the first 48 hours from contact/transfer. Case items are segregated into groups which originate from a common source. A sequence is chosen for taping items from different sources so that potential contamination is minimized. A different lab coat is worn for taping different items. Work area is cleaned before and after taping and mounting. Efficient collection of evidential extraneous hair and fibres. Method of removal (pulled/fallen: difference at root, fallen not viable for dna analysis) Screening hairs for further testing (mitochondrial dna or nuclear dna analysis) Root when pulled has some tissue (follicular tag) so can undergo nuclear dna analysis.
