Ch. 14 Fingerprints

1. Ch. 14 Fingerprints

2. History of Fingerprinting • The first system of personal identification used in criminal investigations was anthropometry. • Anthropometry – developed in 1883 by Alphonse Bertillon • System of precise body measurements

3. History of Fingerprinting

4. History of Fingerprinting • 1892 – Francis Galton – published the textbook, Finger Prints. *impetus for police agencies to adopt fingerprinting as a means of identification • 1891 – Dr Juan Vucetich-developed a classification system still used in many Spanish speaking countries • 1897 – Sir Edward Richard Henry –proposed a classification system used today in most Engish-speaking countries

5. History of Fingerprinting • 1901 - Fingerprints were first used for identification in the US by the New York City Civil Service Commission. • 1924 – Fingerprint records were consolidated into one system by the FBI

6. Principles of Fingerprints • Fingerprints are a reproduction of friction skin ridges found on the palm side of the fingers and thumbs. • The basic principles underlying the use of fingerprints in criminal investigations are that: 1. a fingerprint is an individual characteristic because no two fingers have yet been found to possess identical ridge characteristics; 2. a fingerprint will remain unchanged during an individual’s lifetime; and 3. fingerprints have general ridge patterns that permit them to be systematically classified.

7. First Principle • The individuality of a fingerprint is determined by careful study of ridge characteristics. • Ridge characteristics: Ridge endings, bifurcations, enclosures and other ridge details.

8. Second Principle • Fingerprints are a reproduction of friction skin ridges found on the palm side of fingers and thumbs. • Latent fingerprint-made by the deposit of oils and/or sweat; invisible to the naked eye. • A fingerprint remains unchanged during an individual’s lifetime.

9. Second Principle

10. Third Principle • Fingerprints have general ridge patterns that permits them to be systematically classified • Fingerprints are classified as: • Loops • Whorls • Arches

11. Loops • Loops • Ridge lines enter from one side and curve around to exit from the same side • 60-65% of population • Radial loops open towards thumb • Ulnar loops open toward pinky • Have one delta

12. Whorls • Rounded or circular ridge pattern • 30-35% of population • Two deltas

13. Arches • Ridge lines enter from one side of print and exit out the other • 5% of population

14. Identify each fingerprint pattern. ? A B Right Hand Left Hand C Right Hand E D Right Hand Left Hand

15. Primary Classification • First, fingers are paired up, placing one finger in the numerator of a fraction and the other in the denominator. • The presence or absence of the whorl pattern is the basis for the determination of the primary classification. • If a whorl pattern is found on any finger of the first pair, it is assigned a value of 16; on the second pair, an 8; on the third pair, a 4; on the second pair, a 2; and on the last pair, a 1. • Any finger having a loop or arch is assigned a 0. R. Index R. Ring L. ThumbL. MiddleL. Little R. Thumb R. Middle R. Little L. Index L. Ring

16. Primary Classification • After values for all 10 fingers are obtained, they are totaled, and a 1 is added to both the numerator and denominator. The fraction thus obtained is the primary classification As an example: If the right index finger and right middle finger are whorls and the rest are loops the classification is: 16 + 0 + 0 + 0 + 0 + 1 = 17 0 + 8 + 0 + 0 + 0 + 1 9 • This system allows for 1024 classification groups

17. Automated Fingerprint Identification Systems • 1999- FBI initiated the IAFIS database which linked state AFIS systems to the FBI database • Many AFIS systems exist at the city, county, and local government level

18. AFIS • Scanning devices digitally encode fingerprints bases on the presence and location of ridge endings and bifurcations • A fingerprint can be rapidly scanned and compared with thousands of prints per second. • A search produces a list of possible matches. • The ultimate verification of a prints identity is made by a finger print expert.

19. AFIS • Before AFIS police were limited to comparing crime-scene fingerprints to known suspects • After  police can use crime-scene fingerprints to generate a list of suspects.

20. AFIS There are two major disadvantages of using AFIS systems: • Sometimes a latent print does not make a hit on AFIS because of the poor quality of the file print. • Many different AFIS systems operate at various levels of government using different software systems which prevents them form communicating with each other.

21. Methods of Detecting Fingerprints Three types of Fingerprints • Visible prints – made when the finger deposits a visible material such as ink, dirt, or blood on a surface • Plastic prints – a fingerprint impressed in a soft surface such as wax, soap, clay, etc. • Latent prints – caused by the transfer of perspiration or oils to the surface of an object; usually invisible to the investigator.

22. Locating Fingerprints • Some prints can be visibly identified • Powders or chemicals can be used depending on the surface. • RUVIS – uses ultraviolet light to identify the location of prints on a surface. YouTube - Solved- Fingerprint Analysis

23. Locating Fingerprints

24. On hard surfaces: Powder Grey or black Florescent Magnetic Superglue On soft surfaces: Iodine fuming Nonpermanent visualization Ninhydrin Reacts with proteins AgNO3 Reacts with salt Developing Latent Prints

25. Fingerprint Powders • Used on smooth, non-porous materials. • The area is lightly and carefully dusted with powders of various colors, chosen based on contrast with the surface. • The dust is lifted with tape and set against a contrasting background. • The print is preserved via photography. YouTube - Developing Latent Fingerprints

26. Iodine Fuming • Suspect material is placed in an enclosed cabinet along with iodine crystals. • The crystals are heated, and will sublimate (turn into a gas vapor). • The vapors cause the prints to visualize.

27. Chemical Treatment • Ninhydrin - this chemical is sprayed onto a porous surface via an aerosol can. Prints begin to visualize an hour or two after application, although the process can be accelerated through heating the print. • Silver nitrate- silver nitrate is sprayed onto the porous surface and left to dry. Then it is exposed to ultraviolet light to visualize the prints.

28. Super Glue Fuming • Used mainly on non-porous materials. • Superglue is placed on cotton and treated with sodium hydroxide. • Fumes can also be created by heating the glue. • The fumes and the object are contained in a closed chamber for up to six hours. • The fumes adhere to the print, visualizing it. • YouTube - Developing Fingerprints with Super Glue Prints taken from a plastic bag and developed using super glue fuming

29. Other techniques • Laser light – causes substances found in perspiration to fluoresce. • Chemicals can be added to fingerprints which fluoresce in the presence of laser light • Other techniques have been developed which allow chemicals added to prints to fluoresce with alternative sources of light.

30. Preservation of Developed Prints • Developed prints can be photographed with a specially designed camera. After photographs are taken: • The object containing the fingerprint can be transported to a crime lab • The print can be “lifted” using various types of adhesive tape.

31. Digital Imaging of Fingerprints