FORENSIC SCIENCE - Evidence Retrieval/Forensic Potential etc.

INITIAL SCENE RESPONSE
Safety considerations, initial scene response, secure the scene, walk through
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TYPES OF EVIDENCE
Fragile/Transient, Solid/Tangible
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WHERE WE LOOK FOR EVIDENCE
Access and egress points, where event occurred, suspect if found, vehicle if used, suspect's residence if found, routes/paths between all
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CRIME SCENE SEARCH PATTERNS
Spiral, *****, line, zone/grid, sector
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ORDER OF RETRIEVING EVIDENCE
1 - secure/collect TRANSIENT, FRAGILE OR PERISHABLE EVIDENCE, 2 - secure/collect SOLID/TANGIBLE EVIDENCE, 3 - proceed to other visible items, then those in and out of view or enclosed locations
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RETRIEVAL/COLLECTION - DRY
Hairs/fibres - brushing / J Lar tape / static rod lift, vacuuming for large areas e.g. vehicle. Contact DNA - wet and dry swab. Blood - wet swab only. Saliva - wet and dry swabs. Semen - wet and dry swabs... collect liquid from condoms in Eppendorfs
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RETRIEVAL/COLLECTION - WET
Hairs/fibres - brushing / J Lar tape lift. Contact DNA - mini tape. Blood - cut out or mini tape. Saliva - cut out or mini tape. Semen - cut out
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RETRIEVAL COLLECTION - TOOL MARKS
Tool marks - Mikrosil (brown) 50:50 solution and hardener. Provil Putty (green) not as fine detail. Xanthropen (blue) 50:50 solution and hardener. Silcoset used by Police... toxic chemicals released and very runny
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RETRIEVAL COLLECTION - FOOTWEAR MARK
Removing mark intact: Photography, electrostatic lifting, powdering, Crown-stone casting and Kaffir 'D' plaster, adhesive lifting, gelatine lifting. Chemical methods - Leuco crystal violet, Amido 10 Black, Luminol, Fuschin acid
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RETRIEVAL COLLECTION - GLASS
Collected with tweezers. Each shard numbered and packaged separately
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PACKAGING
Condoms - end of condom should be sealed with freezer clip; put into rigid sterile plastic container. Clothing/shoes - packaged in brown evidence bag with window.. fold top of twice, secure with tape and label
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PACKAGING 2
Weapons - tie down with wire to inner cardboard box with window, seal and label box...give warning of sharp object inside. Glass - each shard no. and packaged separately; wired down into box with window; box into tamper evident bag.
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PACKAGING 3
Small glass - shards into plastic bag; roll up tightly, then into box. Paint - small clear jewellery box. Take 1 sample down to layer of whatever has been sampled. Piece of tape to stop box opening... put blade in with sample
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FORENSIC POTENTIAL: Blood
Evidence of contact: Species of origin, genetic origin. Physical evidence at the scene: location of attack, method of assault, sequence of events. On exhibits: how it could have arisen, sources. BPA helps establish weapon used/distance/force/angle
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FORENSIC POTENTIAL: Hairs/Fibres
VERNON J. GERBERTH in Practical Homicide Investigation, points out that hair/fibre evidence useful in helping to establish scope of crime scene, placing perpetrator at scene, connecting with weapon, supporting witness statements, etc.
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FORENSIC POTENTIAL: Hairs
Hair without follicle: cannot be uniquely matched to individual (making it class evidence). If follicle is attached to hair, you can extract DNA. Determining drug use, toxins, animal?, origin of location on body, whether forcibly removed?
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FORENSIC POTENTIAL: Glass
Refractive index and glass transition temperature help to match up to source. Glass must be classified, e.g. window/broken bottle? Individualisation may be possible... unique pattern/colour etc.
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FORENSIC POTENTIAL: Paint
Raman spectroscopy. Links to source/matching samples. Individual characteristics.
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FORENSIC POTENTIAL: Documents
Graphology (study of handwriting)...can link to person who wrote it / another suspect in case / eliminate / can link to pen (then get evidence from this etc.)
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Other cards in this set

Card 2

Front

Fragile/Transient, Solid/Tangible

Back

TYPES OF EVIDENCE

Card 3

Front

Access and egress points, where event occurred, suspect if found, vehicle if used, suspect's residence if found, routes/paths between all

Back

Preview of the back of card 3

Card 4

Front

Spiral, *****, line, zone/grid, sector

Back

Preview of the back of card 4

Card 5

Front

1 - secure/collect TRANSIENT, FRAGILE OR PERISHABLE EVIDENCE, 2 - secure/collect SOLID/TANGIBLE EVIDENCE, 3 - proceed to other visible items, then those in and out of view or enclosed locations

Back

Preview of the back of card 5
View more cards

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