Fingerprints
Fingerprints in Court It is scientific evidence because… Human friction ridges are unique and permanent No two fingerprints have the same identical ridge characteristics...... Maybe.
3 Types of Fingerprints Latent prints – most often what we think of… Transfer of body perspiration or oils; present on the surface of an object. Plastic prints Fingerprint impressed on a soft surface (putty, soap, or dust) 3. Visible prints Made with visible material (ink, dirt, or blood on a surface)
(mi-NOO-shee-uh) Individual fingerprint determined by: Ridge characteristics (minutiae) Location Number of specific types of minutiae Point by point comparison
Minutiae (mi-NOO-shee-uh) Points Ending Ridge * Double Fork Fork * Delta Short Ridge * Triple Fork Dot Bridge Hook Eye
3 different classes of fingerprints Loop (60-65% of the pop.) Define: ridge lines enter from one side of the pattern and curve around to exit from the same side of the pattern Whorl (30- 35% of the pop.) Ridge patterns that are generally rounded or circular in shape and have two deltas Arch (~ 5 % of the pop.) Ridge lines that enter the print from one side and flow out the other side.
Loops Arch Plain Loop Central Pocket Loop Double Pocket Loop Plain Arch Tented Arch
Methods of Detecting Fingerprints Fingerprint powder Then tape lift Super Glue Fuming: super glue is heated turned to a gas… gas sticks to oils / ridgelines… print dries white Then tape lift or photograph
Methods of Detecting Fingerprints UV light – prints appear orange Then photograph … uses a POLI - LIGHT
Polilights
Quiz Fingerprints change throughout the course of your life. T F
MATCHING: (A – Latent Prints) (B – Plastic Prints) (C – Visible Prints) 2. Made with visible material (ink, dirt, or blood on a surface) 3. Transfer of body perspiration or oils; present on the surface of an object. 4. Fingerprint impressed on a soft surface (putty, soap, or dust)
5. What is the word for individual ridge characteristics 5. What is the word for individual ridge characteristics? Print experts look for about 9 of these for a match.
10-12. Write out what L – A – W stands for.
13. List the tools needed to “lift” or “dust” for prints 13. List the tools needed to “lift” or “dust” for prints. In other words, what do you find in a finger print kit?