tip Fingerprints
Finger and rolled print
History
Bertillon (1883) devised first systematic attempt at personal identification Evidence suggests that Chinese used fingerprints 3000 years ago (sign legal documents) Galton (1892) first book on prints (Finger Prints) Adopted for use in USA in 1901
Three Fundamental Principles
First principle: A fingerprint is an individual characteristic; no two fingers have yet been found to possess identical ridge characteristics Ridge characteristics also called friction ridge skin, characteristics or minutiae
Tested in court Passed Frye and Daubert hearings U.S. v. Bryon Mitchell, 2000
From the Byron case, two court findings
1. Fingerprints (Friction Ridge Skin, FRS) are unique and permanent 2. FRS arrangements are unique and permanent Typical print is blurry, a partial impression, showing only a segment of the entire print
Second Principle
A fingerprint will remain unchanged during an individual's lifetime.
Provides our bodies with firmer grasp and resistance to slippage Shape and form of skin ridges seen as black lines of inked fingerprint
Generic Pattern
Third Principle
Fingerprints have general ridge patterns Permits systematic classification
Three Basic Pattern Classes
Loop
Ulnar (opens toward little finger) and radial (opens toward thumb) Ridge lines enter from one side of pattern and curve around to exit from same side of pattern Contains one delta
Arch
Plain and tented pattern Simplest of all patterns No delta Wave-like pattern
Whorl
Plain, central pocket loop, double loop, accidental Ridge patterns generally rounded or circular with two delta
Note two deltas
Automated Fingerprint ID
AFIS- Automated fingerprint identification system
AFIS
Scans fingerprint image into digital minutiae that contains data on ridge endings and bifurcations Scoring system assigns possible matches, then examined by trained examiner for final verification
Methods of Detecting Fingerprints
Three types of crime prints scene 1. Visible 2. Plastic 3. Latent
Visible Prints
Fingerprint made when finger deposits visible material (ink, blood, dirt) on a surface Detection methods include Leucocrystal violet (blood stained prints)
Plastic prints
Ridge impressions left in a soft surface such as putty, wax, dust
Latent Fingerprints
Latent fingerprintimpressions made by transfer of body perspiration or oils on finger ridges to the surface of an object
Latent Detection Methods
Detection methods include various chemical and powder Detection method depends on type of surface being examined
Chemical latent print development may include:
Ninhydrin Iodine fuming Cyanoacrylate (Super Glue) fuming Physical developer
Ninhydrin reaction with protein
Ninhydrin handprint
Ninhydrin print
Magnetic Powder
Acid Yellow
Gray Powder
Alternate Light Source
Ninhydrin
R.U.V.I.S.
Name that print
Cyanoacrylate Fuming Chambers
Cyanoacrylate prints
Fingerprint dusting
Powder development methods include - magnetic or non- magnetic - colored - black - fluorescent - non- fluorescent
Fingerprint dusting
Fluorescent powder dusting and green magnetic powder
Name that print
Fingerprint dusting
Future CSI?
Preservation of Developed Fingerprint
Visualized latent prints require permanent preservation for future comparison and/or court Photographs must be taken first before other preservation methods are tried
Preservation of Developed Fingerprint
Small objects shipped to lab with print covered with cellophane Large immovable objects must have prints lifted from surface with lift tape After removing print, lift tape is placed on appropriate labeled card
Loop patterns: (a) ulnar loop; (b) radial loop.
Whorl patterns: (e) plain whorl
(f) central pocket loop
Arch patterns: (c) plain arch
(g) double loop
(h) accidental whorl. (d) tented arch.
(FBI)
Web sites
www.swgfast.org www.clpex.com www.onin.com www.theiai.org www.ridgesandfurrows.homestead.com www.latent-prints.com