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Fingerprints and Minutiae. . . Three fundamental principals of Fingerprints. Individual characteristic Will remain unchanged during the individual’s lifetime Have general characteristic ridge patterns that permit systematic classification. History. - PowerPoint PPT Presentation
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Fingerprints and Minutiae
Three fundamental principals of Fingerprints
• Individual characteristic• Will remain unchanged during the individual’s
lifetime• Have general characteristic ridge patterns that
permit systematic classification
History
• Alphonse Bertillon started the identification process with his Anthropometry measurements in 1881
• Francis Galton then upon studying fingerprints and Bertillon's method perfected the fingerprint system and published books in1892 and later Edward Henry simplified his system
• In 1901 Juan Vucetich set up a workable system refining Galton's system and it was used in Spanish speaking countries. He was the first to officially identify a criminal using the fingerprint system
3 TYPES OF FINGER PRINTS
• Latent – prints are not visible until developed made by oils and chemicals this type can be found on any evidence including skin.
• Visible –visible to naked eye—left by a finger that has touched material such as blood , paint etc.
• Plastic or Physical--- Made in soft material such as putty, paint, soap etc.
3 MAJOR PATTERNS OF FINGERPRINTS
• 3 main Patterns consisting of: • Arches – least common• Loops –most common-two sub groups …radial &
ulnar• Whorls- 4 sub groups--- plain whorl- central
pocket whorl- double loop whorl- accidental whorl
• Approximately five percent of all fingerprints are Arches, 30% are Whorls and 65% are Loops.
METHODS OF OBTAINING PRINTS• Some of the most common techniques of finding and lifting prints
include:• Dusting with carbon – dusting with white or black powder to
cover print( most common) can be used with glass, solids plastics etc.
• Super glue fuming – developed in 1970s--leaves white impression• Ninhydrin – reacts/amino acids in fingerprint and leaves purple
image used on matchbooks, newspaper etc.• Silver nitrate- reacts with NACL left from perspiration in the
fingerprint• Laser technology – laser images
INFO
• Fingerprints can last for years• Loop most common• Fingerprints composed of salt, oil, & amino
acids • Latent fingerprints can be left anywhere
including skin• Prints can also be found in feet and palms
even other parts of the body
Arch
Arch
• The Arch pattern has no delta or core; but, it too, must be fully recorded so that its individual characteristics can be readily distinguished.
• Simplest of all fingerprints
Tented arch
Whorl
Whorl
• A Whorl pattern will have two or more deltas. For a whorl pattern, all deltas and the areas between them must be recorded.
• Subdivided into 4 groups—plain whorl, central pocket loop whorl, double loop whorl, and accidental whorl
Loop
Loop
• In the Loop pattern there are two focal points:• the Core, or the center of the loop, and the delta. • The Delta is the area of the pattern where there is a
triangulation or a dividing of the ridges. • Most common type• When recording fingerprints, the delta and the area between
the delta and the core must be completely recorded• Two types of loop: Ulnar loop – opens toward the little finger
and the Radial loop – opens toward the thumb
Minutiae
•Different ridge characteristics in the finger prints
Ridge Ending
• Ridge ending
a single ridge ending within a friction ridge structure
Ridge characteristics/Bifurcation
• BifurcationThe point at which one friction ridge divides into two friction ridges
Enclosure or eye ridge
A single friction ridge that bifurcates and rejoins after a short course and continues as a single friction ridge
Island or short ridge
a single friction ridge that only travels a short distance before termination
Crossover ridge
One ridge crosses Over another ridge Will look like an x
Dot ridge
Small dot by itself in the middle of two or more ridges
Spur ridge
• The spur has a single short ridge that looks like a hook that comes off of a longer ridge.
•µ
Triple bifurcation ridge
• Similar to the bifurcation except it has three ridges coming of the main ridge looks sort of like a fork
Bridge
• Two ridge points are joined together by a short ridge
•
• ≠
Other Characteristics
Scaring…..
Points used for identification
• No legal requirements in the USA for the number of points that must match before deciding that a print matches
• Criminal courts will generally accept 8-12 points.
• Apx 150- 200 minutiae in properly rolled fingerprint.
Match the points
Are they fool proof?• Fingerprints cannot lie however analysis and identification are
subject to error.• Example: Madrid bombings on March 11, 2004 coordinated
train bombings in Madrid Spain killed 191 people ( 911 days after 9/11)
• Bag found with fingerprints identifying Brandon Mayfield, an Organ lawyer..he was held for two weeks while investigated and it turned out after a more thorough analysis the prints were not an exact match…..FBI acknowledged “serious error” in the identification and apologized. Mayfield was not satisfied and sued the U.S. gov and settled for 2 million dollars.
AFIS
• Automated Fingerprint Identification System• FBI system that stores all fingerprints taken –
over 200 million prints on file with FBI• Linked to countries around the world • Decreases the ability of criminals to flee the
country or to commit murders in several different places.