Presentation on theme: "Forensic Aspects of Evidence"— Presentation transcript:
1Forensic Aspects of Evidence Fingerprint Identification“Lifted” from Steve Gilbert, M.F.S., Ph.D.
2History 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)
3History 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
4History of Fingerprints 1903 – West Brothers case in Kansas1904 – First fingerprint bureau1905 – US Army began fingerprinting soldiers1924 – FBI established FP system
5Parts 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
6Embryology 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
7Pattern Anomalies Dissociation of Ridges – no ridges Dysplasia – Faulty development of friction skinCuspal Patterns – ridges run distal to proximal rather than side to side
8LoopsLoops 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.
9Ridge 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)
10Plain ArchRidges enter on one side and flow or tend to flow out the other side with a rise or wave in the center.
11Tented 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.
13Plain 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.
14Central 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.
15Double LoopThe double loop consists of two separate loop formations, with two separate and distinct sets of shoulders and two deltas.
16AccidentalThe 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.
17Major 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
20Fingerprint Classification Henry System Key Major Primary Secondary Subsecondary finalM U IOIL U IOISample classification
21Primary 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
22Primary 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
23Secondary Classification Secondary: the pattern appearing in the index fingers A Arch T Tented Arch R Radial Loop U Ulnar Loop W Whorl
24Subsecondary Classification Subsecondary: grouping according to the ridge counts of loops and ridge tracings of whorls
25Major 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
26Major 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]
27Final 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)
28Key ClassificationKey: ridge count of the first loop appearing on the fingerprint card, exclusive of little fingers
29Fingerprint Processing Powder and brushPhysical developerSmall particle developerNinhydrinCyanoacrylateIodine crystalsThe following images depict laboratory practicums of the junior Fingerprints and Impressions class.