Forensic Paint Analysis. How can paint tell a story?? Able to associate an individual or vehicle...
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Transcript of Forensic Paint Analysis. How can paint tell a story?? Able to associate an individual or vehicle...
Forensic Paint Analysis
How can paint tell a story??
Able to associate an individual or vehicle with a crime scene Hit and Run cases—dried paint/paint smears
transfers to clothing or vehicle upon impact
Burglaries—paint can be transferred onto tools used to break into things
Can identify color, year, make, model of a car by paint recovered at an accident
The vehicle involved in a hit-and-run of a bicyclist who later died left white paint chips at the scene.
Composition
Paint is composed of a binder, pigments, and different additives
Most paint is applied in layers
Paint Layers on Vehicles1. Electrocoat primer—applied to
steel body of car, provides corrosion resistance, pigmented gray-black
2. Primer Surfacer—smooths out and hides seams or imperfections (different pigments)
3. Basecoat—color coat; different additives add different effects (pearl luster, metallic look)
4. Clear coat—unpigmented layer, improves gloss, durability, and appearance
How do we examine paint??
MicroscopeCompare questioned
sample with control (known) sample side by side
Determine type of paint,
Look at surface texture, color, and color layer sequence
Layers—each layer of recovered sample is compared with corresponding layer of the control sample
Paint chip left at a
crime scene can be
compared.
Forensic scientist using a microscope to compare paint chips from a car
involved in an accident with known samples of paint
Collecting paint evidence Picture of paint comparison from hit and run
Malcolm Fairley “The Fox”
1970s British Serial rapist
Detectives found yellow paint specks on a tree at one of the crime scenes
Paint analyzed—comes from a Austin Allegro car
Narrowed suspects—detective drove up at Malcolm’s house, found him cleaning a yellow Allegro
Examined car—found scratches on paint that matched paint flakes to the crime scene
Using this and other pieces of evidence, Malcolm was tried, convicted and sentence to 6 life sentences for rape, assault, and burglary
Gary Ridgeway“Green River Killer”
1970s and 80s—truck painter who killed in Seattle area
Killed between 50-90 women and dumped in Green River
Gary was suspected but never arrested
Killing stop and case goes cold
2001—case is reanalyzed; paint on victims clothing matched to highly specialized paint used at Kenworth truck plant where Gary worked
2002—using paint analysis as well as DNA analysis Gary is found convicted of 48 counts of murder and was sentenced to 48 life sentences