Trace Evidence

Trace evidence is any physical material that is transferred from one object to another. It can be very small, even microscopic, and can be easily overlooked. There are many different types including hair, fibers, gunshot residue, and more. This exercise demonstrates how to collect trace evidence at the scene of a crime.

Objectives

Recognize trace evidence at a crime scene

Collect trace evidence

Preserve trace evidence

Label trace evidence using evidentiary materials

Materials

Mock trace evidence

Tweezers

White paper (computer/notebook)

Envelope (standard)

Clear packing tape

Personal smartphone with camera

Permanent marker

PPE (Suggested)

Procedures

1. Prepare the Crime Scene: Set up mock evidence. Ask a friend or family member to leave a piece of hair, fabric fiber, colored threads, or lint, to name a few, on a surface.

2. (Suggested) Put on PPE: To avoid contaminating the mock evidence and protect clothing, skin, and eyes, put on PPE including gloves, coveralls, headcover, and eye protection.

3. Identify Trace Evidence: Locate the mock evidence (e.g., hair, fabric fiber).

4. Photograph the Trace Evidence: Take a photograph of the trace evidence. This will document what it looked like before it is potentially disturbed, as well as its location.

5. Document Trace Evidence: Record the location of the trace evidence to document its context.

6. Prepare Collection Instrument: To collect the trace evidence, you will fold it in a white piece of paper to secure it. This is known as a druggist fold. To do so, place a white piece of paper down on a steady surface. Fold the paper into thirds as you would for a brochure. Then, unfold the paper.

7. Collect Trace Evidence: Using tweezers, carefully collect the trace evidence and place it in the center of the folded white piece of paper. Refold the paper back into thirds, to look like a brochure. Then fold in half in the same direction of the initial third. Next, fold in thirds overlapping the ends.

8. Secure the Trace Evidence: On one end, create a point by folding in the corners. Next, insert the pointed end into the outermost opening on the other end. Place tape around the initial fold.

9. Label the Trace Evidence: Label the druggist fold pack with your initials, date, and place it in an envelope. Seal the envelope by closing it and taping the envelope flap closed. On the envelope write your initials, date and time of the collection, from where the trace evidence was obtained, and a brief description of the envelope’s contents.