Fingerprints

1. Fingerprints

2. History of fingerprinting • First systematic attempt personal identification devised & introduced by Alphonse Bertillion • Bertillion relied on detailed description of subject, full-length & profile photographs & system precise body measurements (portrait parle and anthropometry • Antropometry bones remained fixed from 20-death; skeleton sizes diverse no 2 individual the same; 11 measurements made

3. History of fingerprints continued • Fingerprints based on ridge patterns came into being and Chinese used them to sign legal documents 3 thousand yrs. ago but may not have been used as we know them • William Herschel required natives sign contracts with imprint right hand but maybe using Hindu custom trace of body contact more binding than signature on contract

4. History of fingerprints • Henry Fauld suggested skin ridge patterns important identification of criminals 1880 • Henry’s system most English speaking countries use • Francis Galton extensive research into fingerprinting published book Finger Prints, first book on subject • Discussed anatomy of fingerprints & methods recording them • Three patterns; loops, whorls, archs

5. History of fingerprinting continued • No two prints alike & eventually method approved along side Bertillion’s • Next step development of fingerprint technology creation of classification system to file the thousands of prints • Edward Richard Henry devised this system that is used at Scotland Yard and a variation in US

6. History of fingerprinting continued • Bertillons’ system fell in disfavor when new prisoner William West came to Leavenworth prison but there was one there same name, measurements & looked like twins, print distinguished them • 1901 first systematic official use of fingerprints personal identification adopted by New York City Service Commission- civil service appplications use

7. History fingerprints continued • FBI largest collection of fingerprints in world • U.S. v. Byron C. Mitchell 1999 defense argued fingerprints not admissible under Daubert • Government agents disputed claim; after Daubert hearing judge upheld admissibility scientific evidence & ruled • Human friction ridges unique & permanent • Human friction ridge skin arrangements unique & permanent

8. Fundamental Principles of fingerprints; First principle • A Fingerprint is an individual characteristic • No two fingers have yet been found to possess identical ridge characteristics • Galton calculated there are 64 billion different fingerprints • Individuality not determined by general shape or pattern but careful study ridge characteristics • A primary classification of 9/3 means that there are whorls on the left index and right ring fingers

9. Fingerprints first principle • Identify, number, & relative location of characteristics impart individuality to print

10. Fingerprints first principle • Judicial proceeding require point-by-point comparison by expert identify individual • 150 or so individual ridge characteristics on average fingerprint • Vast majority of prints recovered are partial & expert compare only a small number ridge characteristics from recovered print & known print; 8 to 16 range ridges needed to meet criteria for individuality • No minimum really exists and final determination left up to expert

11. Fingerprints first principle continued • International Association for Identification 1973 concluded after study no minimum number of characteristics can be used comparison, so identification based on expert knowledge and experience

12. Fingerprints second principle • Fingerprints reproduction of friction skin ridges found on palm side of fingers & thumbs • Friction ridges found on palms & soles of feet • Designed for firmer grip & resistance slippage • Friction ridges look like hills (ridges) & valleys (grooves); skin ridges form prints on paper • Skin composed of layers; outer portion of skin called epidermis; inner layer called dermis

13. Fingerprint second principle • Boundary cells separating epidermis & dermis - dermal papillae & shape of this gives skin its ridges remain unchanged for life; permanently altars prints if damaged

14. Fingerprint second principle • Skin ridges have single row of pores opening for ducts leading to sweat glands; perspiration discharged & deposited on skin surface • Finger touches surface the perspiration along with oils picked up from body & transferred to surface leaving print; latent fingerprint • Attempts to obscure them only serve to make them more distinct; John Dillinger example

15. Fingerprinting Third Principle • Fingerprints have general ridge patterns that permit them to be systematically classified • 60-65% of population has loops; 30-35% whorls; 5% arches • Loops must have one or more ridges entering from one side of the print, re-curving and exiting from the same side

16. Fingerprinting third principle • Ulnar loop- opens toward little finger • Radial loop- opens toward thumb • Type lines are two diverging ridges • At ridge point at or nearest divergence is delta • All loops must have one delta • Core is center of pattern

17. Fingerprinting third principle • Loops

18. Fingerprinting third principle • Whorls divided into four distinct groups • Plain, central pocket loop, double loop, accidental • Must have type lines and minimum 2 deltas • Plain whorl & central pocket loop at least one ridge makes complete circuit • Ridge form of spiral, oval or any variant of circle

19. Fingerprinting third principle • Imaginary line drawn between 2 deltas within 2 patterns & line touches any spiral ridge plain whorl; no such ridge touched pattern central pocket loop • Double loop where two loops combine in one fingerprint • Accidental contains two or more patterns or pattern not covered by other categories; or combination of loop & plain whorl

20. Fingerprints third principle

21. Fingerprint third principle • Arches 2 distinct groups; plain & tented arches • Plain arch simplest & formed by ridges entering one side and exiting opposite side • Ridges rise in center of pattern form wave-like pattern • Tented arch at the center a sharp up thrust or spike instead of like a wave; arches don’t have type lines, deltas or cores

22. Fingerprinting third principle

23. Fingerprint patterns

24. Classification of fingerprints • The primary classification part of original part of Henry system & provides first classification step in FBI system • Fingerprint cards world divided 1024 groups • First step in obtaining primary classification to pair fingers one finger in numerator and other denominator • Presence or absence of whorl patterns basis • Primary classification scheme, the left index finger has a potential value of 4 and other fingers and thumbs are assigned specific numbers

25. Primary classification • About 25% population falls in the 1/1 category all fingers loops or arches • This system gives expert number of candidates that need identification by visual comparison of suspect & files print’s ridge characteristics • Primary classification scheme has the left index finger with a 4 attached to it along with the other fingers and thumbs have special numbers attached to them • Also the number system is based on whether or not the finger or thumb have a whorl on it and they get a number

26. Automated fingerprint identification system (AFIS) • AFIS uses automatic scanning devices that convert image of fingerprint into digital minutiae that contain data showing ridges at their points of termination (ridge endings) & branching of ridges into 2 ridges (bifurcations) • A high-speed computer processes them & prints closest to operator requested criteria • Then prints examined by fingerprint expert

27. Methods of Detecting fingerprints • Three types of prints found at crime scene • Visible prints- fingers touch surface after ridges been in contact with colored material • Plastic prints- ridge impressions left on soft material • Latent prints- caused by transfer body perspiration or oils present on finger ridges to surface of an object

28. Methods of detecting fingerprints • Hard & nonabsorbent surface (metal. glass, mirror, tile) use powder & brush or Super glue • Porous and soft (papers, cardboard, cloth) use treatment one or more chemicals • Reflected Ultaviolet Imaging system (RUVIS) locate prints on nonabsorbent surface by aiming UV light at surface containing prints & print reflected back to viewer & captured light converted into visible light image intensifier

29. Methods of detecting fingerprints • Gray colored powder used surfaces like mirrors & metal surfaces they photograph black • Black powder white or light-colored surfaces • Camel hair brushes used • Magnetic sensitive powders spread over surface with magnet form called Magna Brush; no bristles come in contact with surface so less chance print is damaged • Dusting to visualize a latent print on finished leather & rough plastic is best done with a fiber glass brush

30. Picture of latent fingerprint brush

31. Methods of detecting fingerprints • Fluorescent powders used to develop prints & fluoresce under UV light; photo taken of print under UV light avoid color surface obscure it • Iodine fuming uses solid crystal when heated transform into vapor and form in chamber combine w/constituents of latent print make visible; examiner photos print immediately or use 1% solution of starch in water & spray • Sublimation solid direct to a gas

32. Methods of detecting prints • Print turns blue last several weeks to months • Ninhydrin sprayed on porous surface (paper) & forms purple-blue color with amino acids or protein present in trace amounts in perspiration • Prints begin to appear w/an hour or 2 but weaker prints 24-48 hours; development hastened if heated in oven or hotplate. • Developed prints on paper as old as 15 yrs.

33. Methods of detecting prints • Physical developer silver nitrate-based liquid reagent, effect on former wet porous surfaces & undetectable using previous methods • One wishes to use all previous methods on same surface first fume with iodine, ninhydrin, then physical developer • These methods used on porous surfaces like paper, card board

34. Methods of detecting fingerprints • Super Glue fuming latent print development on nonporous surfaces like metals, electrical tape, leather, plastic bags • Cyanoacrylate ester chemical in super glue interacts w/and visualizes latent print • After heating, fumes & object contained in enclosed chamber up to 6 hours, development occurs when fumes from glue adhere to print producing a white appearing print

35. Methods of detecting fingerprint • Latent prints exposed to laser light visualized because certain components of perspiration fluoresce when exposed to laser light • Substances absorb light & reemits light & can be seen by naked eye or a photo • Latent fingerprints can also be treated with chemicals to induce fluorescence when exposed to laser illumination

36. Methods of detecting fingerprints • Alternate light source are high intensity light that come from quartz halogen that focus on suspect area through fiber optic cable; filters can be used to focus wave length of light • Substitute for Ninhydrin called DFO • DFO visualizes latent prints on porous surfaces when exposed to an alternate light sources

37. Preservation of developed prints • Photograph taken before any further attempts at preservation made • After photograph taken; object small enough to be transported w/o destroying print should be transported in its entirety; print covered w/cellophane • Prints on large immovable objects developed with powder preserved by lifting w/adhesive type tape & put on properly labeled card

38. Preservation of developed prints • Adhesive-backed clear plastic sheet attached to colored cardboard backing can be used

39. Digital imaging for fingerprint enhancement • Digital imaging -process picture converted into digital file made up of pixels or electronic dots • Digital imaging software help enhance fingerprints for more comprehensive & accurate analysis • FFT or frequency Fourier transform used to identify periodic or repetitive patterns such as lines or dots that are interfering with the interpretation of the image • Digital imaging does allow for simultaneous comparison of two prints • After an investigator visualize print a 1:1 photo is taken

40. Digital imaging of fingerprints