Bertillon
1883 first systematic attempt at personal identification (Anthropometry)
Fauld
1880 skin ridge patterns could be important to ID criminals
Galton
1892 No two prints are identical and individuals prints remain unchanged through life
Vucetich
1891 devised a classification system capable of filing many thousands of prints in a logical and searchable sequence.
Sir Edward Henry
Classification systems allowed law enforcement officials to quickly compare prints found at a crime scene to those of known criminals as an aid to identifying potential suspects.
New York City Civil Service Commission
Adopted the first systematic and official use of fingerprints for personal ID
Fingerprints
Reproduction of friction skin ridges
Principles of Fingerprints
1. A fingerprint is an individual characteristic
2. Will remain unchanged during an individuals lifetime
3. Have general ridge patterns that permit them to be systematically classified.
Principle 1
1. No two fingerprints have been found to be identical
2. Individuality is not determined by general shape or pattern, but by careful study of its ridge characteristics (minutiae)
3. Common fingerprint ridge characteristics are bifurcations, ridge endings
Principle 2
1. Friction skin ridges provides our bodies with a firmer grasp and a resistance to slippage
2. Once the dermal papillae is developed in a human the ridge patterns will remain unchanged.
Latent Prints
Once a finger touches a surface perspiration and oil on that finger or hand is then transferred on to the surface that has been touched and is invisible to the eye.
John Dillinger
tried to destroy his own fingerprints by using a corrosive acid on them.
Principle 3
1. All fingerprints are divided into three classes; loops, arches, and whorls.
2. 60-65% have loops, 30-35% have whorls, 5% have arches
Loops
-Must have one or more ridges entering from one side of the print, recurving, and exiting from the same side.
-Pattern area is surrounded by two diverging ridges known as type lines
- Ridge point at or nearest the point where two type lines diverge is kno
Ulnar Loop
Loop that opens toward the little finger
Radial Loop
Loop that opens toward the thumb
Whorls
-Divided into 4 groups; plain, central, pocket loop, double loop, and accidental
-Have type lines and a minimum of two deltas
Plain Whorl/Central pocket loop
-have at least one ridge that makes a complete circuit
-If an imaginary line is drawn between the two deltas and touches any part of the spiral ridges, the pattern is plain. If no ridge is touched then the pattern is central pl.
Double loop
made up of two loops combined to one fingerprint
Accidental
Either contains two or more patterns or is a pattern not covered by the other categories.
Arches
- 2 categories plain and tented
-Plain: is formed by ridges entering from one side of the print rising and falling and exiting the opposite side like a wave
-Tented: Similar to the plain but there is a sharper more pronounced upthrust or the ridges meet a
ACE-V (Analysis, comparison, evaluation, and verification)
4 step process for identifying fingerprints
Comparison Levels
1. general ridge flow and pattern configuration
2. location and comparison of ridge characteristics and minutiae
3. Includes the examination and location of ridge pores, breaks, creases, scars, and other permanent minutiae.
Primary classification
- Henry system updated extending classification capacity and known as the FBI system today.
- (R Index R Thumb) (R Ring R Middle) (L Thumb R Little) (L Middle L Index) (L Little L Ring)
Presence or absence of a whorl is the basis for the primary classific
Whorl pattern classification
First pair 16
Second pair 8
Third 4
Second to Last 2
Last 1
-Any finger with a loop or arch is assigned a 0
-25% of the population has a 1/1 ratio meaning all of their fingers have either loops or arches
-Provides a number of candidates not just one indiv
AFIS
-1999 FBI initiate, contains 50mil fingerprint records,
Livescan
eliminated the need for inked prints
Visible prints
made when fingers touch a surface after the ridges have been in contact with colored material like blood paint grease or ink
Plastic prints
ridge impressions left on a soft material such as putty, wax, soap, or dust.
Powder
used when latent prints are left on hard nonabsorbent surfaces.
Chemical treatment
Latent prints on porous surfaces (papers, cardboard, and cloth) are made visible through the use of
Types of powders
-Gray: used on dark colored surfaces and mirrors
-Black: used on light surfaces
-Magnetic: used on finished leather and rough plastics
-Fluorescent: reveals vivid images of prints under UV light, color surface will not obscure the print itself.
Cyanoacrylate ester
Superglue fuming: used on metals electrical tape, leather, and plastic bags. Fumes from the glue adhere to the print making the print white and visible.
Iodine Fuming
heating iodine crystals that cause vapors through sublimation. Vapors combine with fatty oils or residual water to visualize the print, not permanent and will fade.
Ninhydrin
reacts with trace amounts of amino acids in protein to produce a purple-blue print
Physical Developer
Silver nitrate based reagent, used when no other method is working, develop prints on porous surfaces that may have been wet at some point.
Iodine, Ninhydrin, then PD
Fluorescence
when a substance absorbs light and reemits the light in wavelength longer than the illuminating source.
DFO
1,8-diazafluoren-9-one) a substitute for ninhydrin develops 2.5 times as many prints
IND
(1,2-indanedione) gives good color and fluorescence when exposed to amino acids derived from prints
RUVIS
Reflected UV Imaging system
Preservation of prints
1. Photography
2. Lifting
3. If object is small enough can me moved without compromising the print
4. Digital imaging can enhance the look of prints and compare them but only as useful as the images given to work with