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Characteristics of Fingerprints
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History of Fingerprinting
Used in China to seal documents for 3,000 years Unclear if it was meant for identification Thumbprint was legal signature 1600s-1800s Ridge patterns found on fingertips Ridge patterns broken into 9 groups 1858 William James Herschel developed system of using thumbprints to identify individuals collecting pensions First use for criminal investigation
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History of Fingerprinting
1882 Gilbert Thompson first person to use fingerprints in the United States Also used patterns to identify fraud 1883 First human ID system devised Based upon exact body size Assumed body remained the same after age 20 Consisted of 11 measurements including reach, height, head size, etc. Thrown out around the turn of the century in favor of fingerprints
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History of Fingerprinting
1891 Juan Vucetich is first person to collect fingerprints and keep them on file First person to solve a murder using fingerprint evidence Mother killed her two sons – left a bloody handprint on a door post
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History of Fingerprinting
1892 Francis Galton publishes Fingerprints Cousin of Charles Darwin Setup methods for identification and structure of fingerprints Believed fingerprints were unique and unchanging Odds that two individuals having the same fingerprints is 1 in 64 billion Designs system to categorize large numbers of prints Still in use today
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History of Fingerprinting
1896 Edward Henry developed fingerprinting system to track criminals in England Assigned to Scotland Yard Broke down fingerprints into loops, arches, whorls, and composites 1902 First use of fingerprints in the US for criminal reasons NY state prison system starting fingerprinting its criminals Creates the modern “Ten card”
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History of Fingerprinting
1908 All US Armed Services fingerprint their troops Modern system put into service Uses printers ink and standardized cards 1972 FBI develops first computerized reader of fingerprints Now has the largest collection in world 1998 AFIS (Automated Fingerprint Identification System) is born
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Automated Fingerprint Identification System
International in use Based on laser scanning Database looks for matching characteristics between prints on file and suspect Based on “minutae” Looks at “constellations”
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AFIS
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Fingerprints as Evidence
Has been tested considerably in court Most recent attempt was in 1999 but was ruled admissable Issue is that there is no standard for matching Prints are not matched for 100% accuracy Look to match “constellations” of major features
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Basic Characteristics
No two have ever found to be the same (including twins) Prints remain unchanged throughout an individuals life Individually NOT determined by general shape or pattern Identified by ridge characteristics Point by point matches must be used in court to establish guilt/innocence Average fingerprint contains 150 individual ridge characteristics 8 to 16 characteristics is generally considered adequate for a match in court Even if attempt is made to destroy, some characteristics always grow back
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Structure of Fingerprints
Ridges High points of a print Grooves Low points of prints Epidermis Outermost layer of skin Contains print details Outer covering is Non-living Dermis Inner layer of skin Living tissue Contains sweat and oil glands
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Structure of Fingerprints
Papillae Boundary between dermis and epidermis Determines the form and pattern of prints If an injury is deeper then this layer, scarring will result Pores Each ridge contains one row Used to channel sweat from sweat ducts to the skin’s surface Sweat mixes with oils, etc. and is deposited on any surface the finger touches Often invisible to the human eye and are called latent fingerprints
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Basic Skin Structure
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Major Print Features Ridge Ending Short Ridge Bifurcation Enclosure
The end of a normal ridge Short Ridge A very short ridge Bifurcation One ridge separated into two Enclosure A small section of ridge that forms a loop
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Ridge Classification Categories
Loops 60% - 65% of population Two types Whorls 30% - 35% of population Four distinct groups Arches 5% of population Two distinct groups
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Loop Classifications Loops have three parts 2 Major types of loops
Core Center of the loop Type Line Ridges that diverge from each other Delta Closest ridge to the type lines 2 Major types of loops Radial Loop (Radius = outer arm bone) Loop opens toward the little finger Ulnar Loop (Ulna = inner arm bone) Loop opens toward thumb
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Loop Fingerprint
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Whorl Classifications
Must have type lines and at least two deltas Four types Plain Has at least one ridge that forms a circle or oval An imaginary line drawn between two deltas will cross the circles Central Pocket Whorl An imaginary line drawn between two deltas will not cross the circles
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Whorl Classification Four Types (cont.) Double Loop Accidental
Has two loops combined into one print Accidental Print containing two or more different patterns or not covered in other categories Greater than 2 deltas
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Whorl Fingerprint
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Whorl Fingerprint An example of an accidental whorl. Note the presence of three deltas.
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Arch Classification No loops, type lines or deltas Two groups
Plain arches Simplest of all patterns Ridges enter from one side of the print and exit out the other Ridges tend to rise in the middle of the print “Wavelike” pattern Tent arches Center rises at sharp angle
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Arch Fingerprint
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Fingerprint Analysis Worksheet
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Fingerprint Analysis Worksheet
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Fingerprint Analysis Worksheet
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Fingerprint Analysis Worksheet
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Fingerprint Analysis Worksheet
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Fingerprint Analysis Worksheet
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The FBI “Ten Card” Classification System
The first classification step in the FBI system System divides all fingerprints into one of 1,024 categories Based upon presence/absence of a whorl
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The FBI “Ten Card” Classification System
Fingers are paired according to following method below: R. index R. ring L. thumb L. middle L. little R. thumb R. middle R. little L. index L. ring
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The FBI “Ten Card” Classification System
If a whorl is found on any finger of the first pair, a value of 16 is given ...second pair, value of 8 ...third pair, value of 4 ...fourth pair, value of 2 ...fifth pair, value of 1 Any finger having a loop or arch pattern is given a zero After values for all ten fingers are found, numerators and denominators are added up for a fractional classification number Finally, 1/1 is added to the total value for the final classification
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