Plastic Pieces & Items

Detailed Procedure:

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To collect plastic pieces and items:

1. Photograph the plastic pieces or item in place.

2. Wear new, unused, clean latex or nitrile gloves.

3. Hard plastic fragments can be collected using gloved hands, new or properly cleaned tweezers, or new or properly cleaned forceps. Collect and package samples separately in an appropriate container (box, envelope, new metal paint can, etc.). If latent prints may be present, be sure to secure the item so that it doesn't move around the container and remove the latent prints. Continue with Step 6 below.

4. Small plastic particles may be collected using gloved hands, new or properly cleaned tweezers, new or properly cleaned forceps, or a new brush. Small particles found together at the scene may be packaged in a single container (pillbox, tin, or evidence/pharmacy fold). If the small particles were not found together, they should be packaged separately with their recovery location noted on the label. Continue with Step 6 below.

5. Foam plastic or foam rubber can retain volatile residues such as accelerant, explosives, and gunshot. Items that may bear these residues should be packaged in airtight containers, such as a new metal paint can. Continue with Step 6 below.

6. Seal the container with evidence tape. Initial and date the tape.

7. Label the container with identifying information, including case number, date, exhibit number, a brief description including recovery location, and your name.

8. Store the item in a secure location, such as a locked evidence van or your vehicle, until you are able to transport it to the laboratory.

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Laboratory testing of plastics:

Plastics can be excellent substrates for other evidence, such as toolmarks, volatile residues (accelerant, explosive, gunshot), and fingerprints. In addition, plastic samples can be analyzed and associated based on class characteristics, physical characteristics, and chemical analysis. There is always the possibility of a physical match (puzzle fit) between and questioned and known source. Visual examination may also be able to match questioned plastic fragments and products with a known source, such as a garbage bag torn from a specific roll.

 

Source:

Crime Scene and Evidence Collection Handbook. Bureau of Alcohol, Tobacco, Firearms and Explosives, 2005.