Week 7 Flashcards
Trace Evidence - Taking a paint sample
Take from area of impact
Break a piece off of vehicle, use a holesaw, or scrape
If scraping:
- clean razor or scalpel blade
- scrape down to bare metal
- include blade with sample to lab
Arson Evidence containers
Metal paint cans (lined)
Glass canning jars
Nylon bags
Glass vials with teflon lined cap
Must be a clean and air tight seal!
How to send Arson related exhibits
1) Fire debris:
- Registered mail
- Courier
2) Flammable liquid samples:
- Request TDG package from TES lab
- Send via Courier back to lab
Package liquid samples SEPARATELY from fire debris samples
Plackage clothing seperate from fire debris samples
Place correspondence on exterior of box
GSR: how long does it stay on the body?
Not adhesive, like a fine dust
Adheres to skin, easily removed
4 hours, 90% of residue is lost from hands
- Washing
- Touching
- Wiping
On face, up to 24 hours
- Lab will ONLY TAKE within 12 hours
GSR Kit
Adhesive tape lift
- Glue
- Traps GSR
- Removes residue from skin/clothing
One inch adhesive coated stubs
Protective cap
- Sealed
Unique serial number
- Traceability
Labels
Face
- 2 stubs (L/R)
Hands
- 2 stubs (L/R)
Conclusions of GSR
1) Fired a firearm
2) In close proximity to discharge of firearm
3) Contact with other source of GSR (2nd transfer)
Post Mortem Lividity
The settling of blood after death
Can assist in sequence of events; was the person moved?
3 steps to take when processing a suspect
1) Photograph:
The suspect BEFORE anything is seized or swabbed
2) Examine: Hands, face, exposed skin for injuries - Photograph with scale - Swab bloodstains - Powder residue - GSR kit?
3) Samples:
Appropriate to offence
- hair, saliva, blood, nail clippings
- General Warrant, DNA, Incidental to offence
ACS Processing - Exhibit Photography
Photograph prior to seizing or processing
At Scene:
- Overall, mid-range, close-up
- Exhibit number in photo
At Office:
- Studio Photography with scale and lighting
- Overall (sealed - both sides)
- Overall (opened)
- White Light exam
- Photograph any visible impressions
- Overall/mid-range after development
Swab process
Clean gloves between each swab
Mask at all times
1) Identify area for swabbing
- Mark as you would fingerprint
- Unique Identifier (S1)
2) If blood:
- Hemastix test (indirect - use swab)
- Mark H+/H- by markings
3) Photograph with scale
- Overall, mid-range, close-up
4) Moisten tip, apply to area of interest
5) Rolling motion
6) Concentrate on the tip
7) Return swab to container
- Ensure its able to dry
8) Mark container with swab #, initials, date and time seized
9) Secure in paper envelope or bag with:
- File #, Exhibit #, description, Initials, date and time seized
Exhibits: Bloody Clothing
1) Seize each individually
2) Clean paper Exhibit bags against clothing if you have to fold
- helps prevent transfer of bloodstains
3) Sterile hanger, place in bag, transport to drying chamber
4) Mark:
- Exhibit #, File #, Description, Initials, date and time seized, time handed over
Exhibits: Weapons
1) Knives
- Photograph in situ
- Package in weapons box
- …or safe as possible and mark sharp…
2) Firearms
- Photograph in situ
- Condition found:
- loaded, empty, open chamber, etc.
- Render safe
- Package in weapons box
Studio photography
White light exam
CA (block barrel/mag chamber on guns)
Re-examine white light exam
Photograph prior to dye stain any impressions
Dye stains; ALS
Photograph any impressions
Repackage, mark ‘Chem Treated’
Return to invest or Exhibit custodian
What is bloodstain pattern analysis
The examination of the size, shape, Location and distribution pattern of bloodstains, in order to provide an interpretation of the physical events which gave rise to their origin.
What is the basic fundamental principle of bloodstain pattern analysis
They are:
1) Predictable
2) Reproducible
3 bloodstain pattern categories
1) Gravity
- drip stain
- accompanying drop
- drip pattern
- satellite
- drip trail
- flow
- splash
- pool
2) Spatter
- impact
- cast-off
- cessation cast-off
- projected
- expiration
3) Transfer
- swipe
- wipe
- saturation
VOID! Absence of blood in an otherwise continuous bloodstain.
