Presentation on theme: "Forensic Science T. Trimpe 2007"— Presentation transcript:
Forensic Science T. Trimpe 2007 http://sciencespot.net/
Latent prints are impressions left by friction ridge skin on a surface, such as a tool handle, glass, door, etc. Prints may be collected by revealing them with a dusting of black powder and then lifted with a piece of clear tape. Did you know? Camel hair is the most common animal hair used to make fingerprint brushes. Now many brushes (like the one above) are made out of fiberglass.
The cyanoacrylate fuming method (often called the super glue method) is a procedure that is used to develop latent fingerprints on a variety of objects. Bottom Right: http://www.forensicsrus.com/images/SupergluePrint.jpg Magnetic powder can also be used to reveal latent prints. This type of powder works better on shiny surfaces or plastic baggies or containers. Top Left: http://www.stapletonandassociates.com/images/MagPowder.jpg Bottom Left: http://www.ok.gov/osbi/images/ninhydrin%20print.jpg Click the icon to view the Crime 360 Super Glue Video Some investigators use fluorescent powder and UV lights to help them find latent prints on multi-colored or dark surfaces. Ninhydrin is a chemical that bonds with the amino acids in fingerprints and will produce a blue or purple color. It is used to lift prints from surfaces such as paper and cardboard.
Directions ① Cover work area with white paper. ② Get Latent Print kit from Ms. Evans (powder, brush, tape, slide) ③ Press right thumb against nose, chin, or forehead. Then press right thumb against glass slide. ④ Dip brush LIGHTLY in powder. Tap excess powder on lid. You only need a SMALL amount. ⑤ Hold brush over top of thumb print. Lightly brush print. Cover entire print lightly with powder. Tap slide against paper to remove excess powder. ⑥ Use a small piece of tape to lift print. Place tape on top of print and then pull it off slowly. ⑦ Place piece of tape with print in the box on your Latent Print notes.
Clean Up ① Clean off slide with wipe. ② Place clean slide back into Latent Print Kit. ③ Place ALL clean materials back into kit. ④ Place dirty wipe on white paper. Fold white paper in half to capture any excess paper. ⑤ Throw away paper in trashcan by the door. ⑥ Clean off work area (table) with wipe and throw away. ⑦ Sit quietly when finished until the class is ready to move on! CONGRATULATIONS – You just lifted your own fingerprint!