Presentation on theme: "Forensic Aspects of Evidence"— Presentation transcript:
1 Forensic Aspects of Evidence Fingerprint Identification“Lifted” from Steve Gilbert, M.F.S., Ph.D.
2 History of Fingerprints 1684 – Nehemiah Grew reported that various patterns were present in the fingers1685 – Bidloo produced first fingerprint drawing1823 – Johannus Purkinje wrote a commentary of the skin system1880 – Henry Faulds stated that chance prints at scenes could identify perpetrator (Faulds)
3 History of Fingerprints 1892 – Francis Galton wrote his book called “Fingerprints”. Studied over 40,000 prints and failed to find any matches1901 – Sir Edward Henry established the first and continuing classification system1902 – New York began collecting fingerprints of job applicants
4 History of Fingerprints 1903 – West Brothers case in Kansas1904 – First fingerprint bureau1905 – US Army began fingerprinting soldiers1924 – FBI established FP system
5 Parts of the Hand Distal II III I IV Radial Ulnar Proximal Inter Digital IntervalsMeta Carpal CreaseThenar EminenceIIIIIInter Digital Pads I - IVIIVRadialUlnarProximal Traverse CreaseHypo Thenar EminenceDistal Traverse CreaseBracelet CreaseProximal
6 Embryology 6 weeks: pads II, III, IV 8 weeks: finger elongate, separate8-12 weeks: pads round, separate pads13 weeks: pads regress smaller3-4 months: ridges formThe number ridges dictated by fullness of finger pad
7 Pattern Anomalies Dissociation of Ridges – no ridges Dysplasia – Faulty development of friction skinCuspal Patterns – ridges run distal to proximal rather than side to side
8 LoopsLoops opening towards the little finger is the ulnar loop, whereas the loop opening towards the thumb is the radial loop.One or more ridges enter on either side, recurve, touch or pass an imaginary line drawn from the delta to core, and terminate or tend to terminate on or toward the same side the ridge or ridges entered.
9 Ridge CountingRidge count: 19 The line must touch the ridge to be counted.The number of ridges intervening between the delta and the core is known as the ridge count. (yellow tick marks)
10 Plain ArchRidges enter on one side and flow or tend to flow out the other side with a rise or wave in the center.
11 Tented ArchRidges enter on one side and flow or tend to flow out the other side, however the ridges in the center do not. This possesses an angle.
13 Plain WhorlsIf an imaginary line drawn between both deltas crosses or touches a recurving ridge in the inner pattern area, the pattern is consider a plain whorl.The plain whorl has two deltas and at least one ridge making a complete circuit, which may be spiral, oval, circular, or any variant of a circle.
14 Central Pocket LoopThe central pocket loop has two deltas and at least one ridge which makes or tends to make a complete circuit. The circuit may be spiral, oval, circular or any variant of a circle. An imaginary line drawn between the two deltas must not touch or cross any recurving ridges within the inner pattern.
15 Double LoopThe double loop consists of two separate loop formations, with two separate and distinct sets of shoulders and two deltas.
16 AccidentalThe accidental is a pattern consisting of a combination of two different types of patterns, with the exception of the plain arch, with two or more deltas; or a pattern which possesses some of the requirements for two or more different types; or a pattern which conforms to none of the definitions.
17 Major Parts of PrintsPattern area: appears in a loop or whorl in which appear the cores, deltas and ridgesCore: approximate center of the printDelta: that point on a ridge at or in front of and nearest the center of the divergence of the type lines
20 Fingerprint Classification Henry System Key Major Primary Secondary Subsecondary finalM U IOIL U IOISample classification
21 Primary Classification Primary: Values of whorls Finger value assignments: Fingers 1 & 2: 16 Fingers 3 & 4: 8 Fingers 5 & 6: 4 Fingers 7 & 8: 2 Fingers 9 & 10: 11 is added to all primary classifications1 over 1 indicates no whorls32 over 32 indicates no whorls
22 Primary Classification Where whorls appear in the fingers, the values are added, even over odd, with 1 added to the total. In this card, the right hand has =29 The left hand: =19Even fingersOdd fingers
23 Secondary Classification Secondary: the pattern appearing in the index fingers A Arch T Tented Arch R Radial Loop U Ulnar Loop W Whorl
24 Subsecondary Classification Subsecondary: grouping according to the ridge counts of loops and ridge tracings of whorls
25 Major ClassificationMajor: Where whorls appear in the thumbs, the major division reflects whorl tracings (inner, outer, meeting)If loops appear in the thumbs, ridge counts are used
26 Major Classification Table Left Thumb Denominator Right Thumb Numerator01-11 Small………………………..[01-11, Small][12-16, Medium][17+, Large]12-16 Medium…………………….. [01-11, Small]17 or more, Large…………………..[01-17, Small][18-22, Medium][23+, Large]
27 Final ClassificationFinal: ridge count of the right little finger. *If not: ridge count in the left little finger *If not: a whorl is used * left delta to core (right hand) * right delta to core (left hand)
28 Key ClassificationKey: ridge count of the first loop appearing on the fingerprint card, exclusive of little fingers
29 Fingerprint Processing Powder and brushPhysical developerSmall particle developerNinhydrinCyanoacrylateIodine crystalsThe following images depict laboratory practicums of the junior Fingerprints and Impressions class.
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