Fingerprinting

1. Fingerprinting Courtesy of C. Fanning Crystal Violet Chapter 15 Courtesy of C. Fanning Courtesy of C. Fanning Red Fluorescent Inked

2. The first systematic attempt at personal identification was devised by a French police expert, Alphonse Bertillion. • The Bertillion system relied on a detailed description of the subject, combined with full length and profile photographs and a system of precise body measurements called anthropometry. History

3. Fingerprinting • What was needed was the creation of classification systems capable of filing many thousands of prints in a logical and searchable sequence. • Sir Edward Henry devised a classification system used in most English-speaking countries. • Cont. Chapter 15

4. After the Will West incident, the use of fingerprinting by the New York City Civil Service Commission in 1901, and the training of American police by Scotland Yard representatives at the 1904 World’s Fair, fingerprinting began to be used in earnest in all major U.S. cities.

5. Fingerprints are a reproduction of friction skin ridges found on the palm side of the fingers and thumbs. • Three Fundamental Principles • Fingerprints show individual characteristics • Fingerprints do not change over a lifetime • Fingerprints have ridge patterns that can be easily classified I. Fingerprint Principles

6. The probability for the existence of two identical fingerprint patterns in the world’s population is extremely small. • Besides theoretical calculations, of the millions upon millions of individuals who have had their prints classified, no two fingerprints have been found to be identical. • Cont. A. Principle One

7. Principle One: No two fingerprints look alike cont… • Classified by ridge patterns • If two fingerprints are to match - ridge patterns must be identical in both characteristics and • location on the finger • No national standard but 8-16 ridge patterns are needed between a unknown and known fingerprint for there to be

9. B. Principle Two: Fingerprints stay the same over a lifetime • Friction ridges found on lips, fingers and palms of hands and soles of feet • Outer layer of skin - epidermis • Inner layer - dermis • Junction between the two layers is - dermal papillae • John Dillinger tried to obliterate his finger prints by making deep cuts and pouring sulfuric acid into the cuts. Within a few years the same friction ridge patterns returned with some scaring. Post Mortem fingerprints taken by the FBI confirmed that his prints were unchanged.

11. Principle Two cont… • Raised lines or hills - Ridges • The valleys between the hills - Grooves • Pores in between the ridges are openings for sweat glands • Sweat and oils leave an impression on the surface called a latent print

12. C. Principle Three: Classified Ridge Patterns • Three Ridge Classes: LOOPS - 60 to 65% WHORLS - 30 to 35% ARCHES - 5% Percentage of the patterns found on the epidermis in the general population

13. Classification

14. The heart of AFIS technology is the ability of a computer to scan and digitally encode fingerprints so that they can be subject to high-speed computer processing. • AFIS aids in classifying and retrieving fingerprints by converting the image of a fingerprint into digital ridges that contain data showing ridges at their points of termination (ridge endings) and their branching into two ridges (bifurcations). AFIS (AUTOMATED FINGERPRINT IDENTIFICATION SYSTEM)

15. II. DETECTING FINGERPRINTS • Types of Prints • Three kinds of crime scene prints: • Visible – can be seen without technology • Latent – not visible without some technology • Plastic – impressions made in soft materials such as soap, wax or putty • Visible and plastic are easy to find but latent is more difficult

16. DETECTING FINGERPRINTS B. Locating fingerprints Different surfaces require different visualizing methods Hard non-porous surfaces (glass, tile, painted wood) require visualizing powders or Super glue Soft and porous surfaces (cloth, paper, cardboard) require chemical treatment

17. C. DEVELOPING LATENT PRINTS 1. POWDERS: • Adhere to perspiration and body oils • Almost any color – grey and black being most common • Grey – aluminum dust • Black –carbon or charcoal • Fluorescent – glow under UV light Video – Developing Fingerprints with Powder

18. Super Glue fuming develops latent prints on nonporous surfaces, such as metals, electrical tape, leather, and plastic bags. • Development occurs when fumes from the glue adhere to the print, usually producing a white latent print. 2. Super Glue

19. Prints on porous surfaces (e.g., papers, cardboard, and cloth) generally require treatment with a chemical. • Examiners use various chemical methods to visualize latent prints on porous surfaces, such as: • iodine fuming • ninhydrin • Physical Developer 3. Chemical treatments

20. Iodine fuming involves heating iodine crystals that cause vapors which combine with latent prints to make them visible. • Iodine prints are not permanent and will fade, making it necessary to photograph the prints immediately. • Ninhydrin reacts chemically with trace amounts of amino acids present in latent prints to produce a purple-blue color. • Physical Developer is a silver nitrate-based reagent used to develop prints when other chemical methods are ineffective. Chemical Treatment

21. DETECTING FINGERPRINTS • Can use RUVIS (Reflected Ultraviolet Imaging System) which locates prints on soft surfaces without the use of chemicals with UV light RUVIS

22. PRESERVING DEVELOPED PRINTS If the object the print is on is small – the entire object should be taken to the laboratory If the object is too large - then the developed print must be “lifted”. Can use special clear tape to lift a print developed with a powder Tape with print is placed on a card with good background contrast • Once a print is developed it must be preserved as evidence • STEP ONE: photograph developed print • STEP TWO is determined by the size of the object the print is on

23. DIGITAL IMAGING Digital imaging converts a fingerprint image into pixels Can be done with a scanner or digital camera • Lifted fingerprints are not usually in perfect condition – making analysis even more difficult • Digital imaging programs can now enhance the lifted/partial prints to make identification more accurate

24. END

25. Integrated Automated Fingerprint Identifcation System (IAFIS) Ridge endings (terminations) Branching of ridges (bifurcations) Screen out imperfections in latent prints Can send prints immediately to FBI database • Ability of the computer to scan and digitally encode fingerprints • The encoding allows ridges to be rapidly scanned • Can screen a set of 10 prints against a file of 500,000 sets of 10 prints in .08 seconds

26. DEVELOPING LATENT PRINTS • POWDERS: • Adhere to perspiration and body oils • Almost any color – grey and black being most common • Grey – aluminum dust • Black –carbon or charcoal • Magnetic – charged • Fluorescent – glow under UV light

27. DEVELOPING LATENT PRINTS • FUMING: • Super glue (Crazy glue) • can visualize a print on non-porous surfaces as well as metals, tape, leather and plastic bags • Heating the Super glue releases cyanoacrylate ester fumes • Fumes produce a white fluffy print FUMING: Iodine iodine sublimates when heated giving off fumes. The iodine fumes adhere to the latent print Old technology – does not last long print visible fades in minutes

28. DEVELOPING PRINTS • FUMING: • NINHYDRIN • The chemical reacts with amino acids to produce a purple-blue color • Usually used as an 0.6 % solution sprayed as an aerosol on porous surfaces • Takes 1 to 48 hours can increase developing by heating in an oven • Effective on paper that was 15 years old

29. DEVELOPING PRINTS NEWEST TECHNOLOGY Laser light can detect latent prints that fluoresce with certain components of sweat. Alternate light sources: High-intensity quartz halogen Xenon-arc LED’s (light emitting diodes) DFO (1,8-diazafluoren9-one) Chemical works with alternate light sources • PHYSICAL DEVELOPER • Chemical mixture – silver nitrate based • Works even if item was wet –then dried. • Used as the “last resort” because washes away all traces of proteins