Download Fingerprints

 Discovered that they are unique. No 2 alike.
 A classification system was developed.
 Loops
 Whorls
 Arches
 Computer database
 AFIS Automated Fingerprint Identification System
 1990
 IAFIS Integrated Automated Fingerprint Identification
System
 Criminal histories; mug shots; scars and tattoo photos;
physical characteristics like height, weight, and hair and eye
color; and aliases.
 Response time:
 10 minutes for electronically submitted criminal prints.
 One hour for electronically submitted civil prints.
 Loop – comes in one side and out that same side. One
delta on the side opposite from where it starts and
exits. Most common
Turn
Enter
Delta
Exit
 Whorl – Circular shape. Two deltas on either side.
Delta
Delta
 Arch – Up thrust, with a decline. Exits opposite side.
Up Thrust
Enter
Exit
 Plastic – finger contacts a soft surface such as putty.
 Visible. Finger is covered with a liquid such as blood
and then contacts a hard surface.
 Latent – Invisible. Oils, salts and other debris stick to
a surface when it is touched by a finger. Most
common.
 Lighting – flash light, etc.
 Chemical reaction
 Iodine mixes with starches in the fingerprint and turns
brown
 Ninhydrin mixes with the amino acids in the
fingerprints and turns purple.
 Dusting with fingerprint powder
 Gray – aluminum dust
 Black – carbon or charcoal
 Ultraviolet image converter – Reflected Ultraviolet
Imaging System (RUVIS)
 Iodine Fuming
 Not permanent
 Must be photographed
 Ninhydrin
 Amino acids
 Turns purple within an hour or two.
 Physical developer
 Silver nitrate based liquid reagent
 Good for porous surfaces
 Used for slick surfaces.
 Superglue and dusting.
 Identifying the pattern (loop, whorl, arch)
 Looking for minutiae
 Ridge ending
 Bifurcation
 Island
 Core
 Delta
 Cicatrix
 What do you compare a lifted print to?
 A known sample
 How many points does the FBI use in identifying a
print?
 14
 How does a fingerprint match become confirmed?
 With a microscopic match by a human being.