dusting.html
History
Fingerprints at the Crime Scene
Now that you have classified fingerprints, how can they be identified when found at a crime scene?
Fingerprints must be removed and transported to the crime lab. They are then compared to the database of fingerprints on file. One way that detectives locate fingerprints is by dusting for them. Fingerprints are coated with powder, then lifted and taken for identification at the lab.
Try your hand at being a detective by dusting for fingerprints. You will need the materials listed on the right.
Dusting a Glass
1. When fingers are oily or sticky you get better fingerprints. So press an oily or sticky finger on the side of a drinking glass.
2. Coat the fingerprints with a dusting of cocoa powder.
3. Brush gently with either a camelhair or fiberglass brush. The fingerprints remain.
4. Place the sticky side of the tape on the dusted fingerprint. Lift on the tape and place on light colored construction paper.
- Talcum powder should be used on dark surfaces.
- The dusting method is used to lift prints from hard surfaces. Lifting prints from smooth surfaces requires chemicals.
Materials List
Drinking glass
Cocoa
Small soft brush (soft camel hair or fiberglass)
Transparent tape
5 sheets of light-colored construction paper
