Fingerprints

1. Fingerprints

2. Objectives You will understand: Why fingerprints are individual evidence. Why there may be no fingerprint evidence at a crime scene. How computers have made personal identification easier.

3. Objectives, continued You will be able to: Define the three basic properties that allow individual identification by fingerprints. Obtain an inked, readable fingerprint for each finger. Recognize the general ridge patterns (loops, whorls, and arches). Identify friction ridge characteristics and compare two fingerprints with at least ten points of identification. Explain the differences among latent, plastic, and visible fingerprints. Develop latent prints (make them visible) using physical and chemical methods.

4. History from 1850 to 1900 William Herschel—required Indians to put their fingerprints on contracts, and used fingerprints as a means of identifying prisoners Henry Faulds—claimed that fingerprints did not change over time and that they could be classified for identification Alphonse Bertillon—proposed body measurements as a means of identification; termed anthropometry Francis Galton—developed a primary classification scheme based on loops, arches, and whorls Edward Richard Henry—in collaboration with Galton, instituted a numerical classification system Juan Vucetich—developed a fingerprint classification system based on Galton’s that is used in Spanish-speaking countries DactyloscopyThe Study of Fingerprints

5. Recording and classifying prints Rolling inked prints Loops, whorls, arches, ridge characteristics Primary identification number Lifting prints Black, white, and fluorescent powder Chemicals—ninhydrin, iodine, silver nitrate, cyanoacrylate Other types of prints Palm, lip, teeth, eye, ear, voice, shoeprints, and footprints

6. Fundamental Principles of Fingerprints • A fingerprint is an individual characteristic. • A fingerprint remains unchanged during an individual’s lifetime. • Fingerprints have general characteristic ridge patterns that permit them to be systematically classified. • Fingerprints are a reproduction of friction skin ridges found on the palm side of the fingers and thumbs. • No two fingers have yet been found to possess identical ridge characteristics.

7. Cross Section of Human Skin Boundary between epidermis and dermis is the dermal papillae, which determines the form and pattern of the ridges on the surface of the skin. Once this develops in the human fetus, the ridge patterns remain unchanged throughout life except to enlarge during growth.

8. Forensic examiners look for the presence of a core (the center of a whorl or loop) and deltas (triangular regions near a loop). A ridge count is another characteristic that distinguishes one fingerprint from another. The count is made from the center of the core to the edge of the delta. Characteristics of Fingerprints

9. Ridge Characteristics Minutiae—characteristics of ridge patterns Ridge ending Island or short ridge Bridge Eye or enclosure Delta Bifurcation or fork Dot Spur Double bifurcation Trifurcation The individuality of a fingerprint is determined not by its general shape or pattern, but by a careful study of its ridge characteristics. Prints deposited in this manner are invisible to the eye and are commonly referred to as latent or invisible fingerprints.

10. Fingerprint Minutiae

11. Can fingerprints be erased? No, if, for example, they are removed with chemicals, they will grow back. Is fingerprint identification reliable? Yes, but analysts can make mistakes. Is fingerprint matching carried out by computers in a matter of seconds? No, but the FBI’s Integrated Automated Fingerprint Identification System (IAFIS or AFIS) can provide a match in 2 hours for the prints in its Master File. Fingerprint Forensic FAQs

12. LOOP WHORL ARCH

13. Arch An arch has friction ridges that enter on one side of the finger and cross to the other side while rising upward in the middle. They do NOT have type lines, deltas, or cores. Types Plain Tented About 5% of the population have arches.

14. Loop A loop must have one or more ridges entering and exiting from the same side. Loops must have one delta. Types Radial—opens toward the thumb Ulnar—opens toward the “pinky” (little finger) Which type of loop is this, if it is on the right hand? Left hand? 60-65% of the population have loops.

15. Whorl A plain or central pocket whorl has at least one ridge that makes a complete circuit. A double loop is made of two loops. An accidental is a pattern not covered by other categories. Whorls have at least two deltas and a core. Types Plain Central pocket Double loop Accidental 30-35% of the population have whorls.

16. Primary Classification The Henry-FBI Classification System Each finger is given a point value. right left

17. Assign the number of points for each finger that has a whorl and substitute into the equation: The primary classification is the first step in classifying fingerprints under the FBI system. The presence or absence of the whorl pattern is the basis for determination of the primary classification. Primary Classification, continued right right left left left index ring thumb middle little + 1 = right right right left left thumb middle little index ring + 1 That number is your primary classification number.

18. The Automated Fingerprint Identification System—a computer system for storing and retrieving fingerprints Established in the 1970s, AFIS enables law enforcement officials to: Search large files for a set of prints taken from an individual Compare a single print, usually a latent print developed from a crime scene By the 1990s, most large jurisdictions had their own system in place. The problem: A person’s fingerprints may be in one AFIS database but not in others. IAFIS—the FBI’s Integrated Automated Fingerprint Identification System, which is a national database of all 10-print cards from all over the country AFIS

19. AFIS Can be operated by cities, counties, other local government Often cannot be linked with state’s AFIS system because of differences in software configurations IAFIS Integrated AFIS Largest AFIS in USA Links state AFIS computers with the FBI database Contains nearly 50 million fingerprint records Automated Fingerprint Identification Systems The database converts the image of a fingerprint into digital minutiae that contain data showing ridges at their points of termination (ridge endings) and their branching into two ridges (bifurcations). Livescan is an inkless device that captures digital images of fingerprints and palm prints and electronically transmits them to an AFIS.

20. Comparison There are no legal requirements in the United States on the number of points required for a match. Generally, criminal courts will accept 8 to 12 points of similarity.

21. https://youtu.be/IrpTqKkgygA Matching Minutiae (must show 8-10) 1. 2. 3. . . . 14.

22. Visible prints (or patent prints) are made when fingers touch a surface after the ridges have been in contact with a colored material such as blood, paint, grease, or ink. Plastic prints are ridge impressions left on a soft material, such as putty, wax, soap, or dust. Visible and Plastic Prints

23. Latent fingerprints are those that are not visible to the naked eye. These prints consist of the natural secretions of human skin and require development for them to become visible. Most secretions come from three glands: Eccrine—secretes largely water, with both inorganic (ammonia, chlorides, metal ions, phosphates) and organic (amino acids, lactic acids, urea, sugars) compounds. Most important for fingerprints. Apocrine—secretes pheromones and other organic materials. Sebaceous—secretes fatty or greasy substances. Latent Prints

24. Developing a print requires substances that interact with secretions, causing the print to stand out against its background. It may be necessary to attempt more than one technique, done in a particular order so as not to destroy the print. Nondestructive Recovery: Developing Latent Prints Powders—adhere to both water and fatty deposits. Choose a color to contrast with the background. Iodine—fumes react with oils and fats to produce a temporary yellow-brown color.

25. Developing a print requires substances that interact with secretions that cause the print to stand out against its background. It may be necessary to attempt more than one technique, done in a particular order so as not to destroy the print. Powders—adhere to both water and fatty deposits. Choose a color to contrast the background. Best used on nonporous surfaces. Gray for mirrors and dark surfaces, Black for light-colored surfaces Magnetic powder good for rough surfaces Fluorescent powders are used with UV light so surface color is obscured Developing Latent Prints

26. Iodine Fingerprint • Iodine—fumes react with oils and fats to produce a temporary yellow brown reaction. • Prints fade, so they must be photographed or “fixed” Note the brownish color.

27. What does one do with the developed print ? • Photograph the print with a close-up lens • Cover print with cellophane tape, preserve entire object containing print • “Lift” print off larger objects with clear tape, mount on backing card Kendall/Hunt Publishing Company

28. Destructive Recovery Methods: • 3. Ninhydrin—reacts with amino acids to produce a purple or pink color. • Preferred method of chemical development on porous surfaces like paper Note the pink color.

29. Silver nitrate—reacts with chloride to form silver chloride, a material which turns gray when exposed to light. AgNO3(aq) + NaCl(aq)  AgCl(s) + NaNO3(aq) Useful on porous surfaces that may have been wet or sweaty at one time Cyanoacrylate—“super glue” fumes react with water and other fingerprint constituents to form a hard, whitish deposit. Used on nonporous surfaces such as metals, electrical tape, leather, plastic bags. In modern labs and criminal investigations, lasers and alternative light sources are used to view latent fingerprints. These were first used by the FBI in 1978. Since lasers can damage the retina of the eye, special precautions must be taken.

30. Cyanoacrylate Fingerprints Note the white color.

32. Hard and nonabsorbent surfaces are usually developed by application of a powder Porous surfaces (papers, cardboard) generally require treatment with a chemical Iodine fuming, ninhydrin, silver nitrate Super Glue fuming develops prints on nonporous surfaces Chemically induced fluorescence, visible when exposed to laser or ALS (alternate light source) Key Points - Latent Prints

33. New scanning technologies and digitally identifying patterns may eliminate analytical mistakes. Trace elements of objects that have been touched are being studied to help with the identification of individuals. To help with identification, other physical features such as eyes and facial patterns are also being studied. The Future of Fingerprinting

34. Video What is the pattern of Mayfield’s print and that of the prime suspect? How are they similar? How are they different?

35. Lips—several common patterns Voice—electronic pulses measured on a spectrograph Foot—size of foot and toes; friction ridges on the foot Shoes—can be compared and identified by type of shoe, brand, size, year of purchase, and wear pattern Other Prints

36. Other Prints, continued Palm—friction ridges can be identified and may be used against suspects

37. Other Prints, continued Footprints are taken at birth as a means of identification of infants.

38. Other Prints, continued A man has been convicted of suffocating an eldery woman on the basis of earprint evidence. The assailant was caught after police matched the inprint of his ear on the victim’s window. Police believe that the thief put his ear to the window to listen for signs of anyone home. Earprint catches murderer

39. Other Prints, continued Teeth—bite marks are unique and can be used to identify suspects. These imprints were placed in gum and could be matched to crime scene evidence.

40. Other Prints, continued The blood vessel patterns in the eye may be unique to individuals. They are used today for various security purposes.

41. Other Prints Lips—display several common patterns • Short vertical lines • Short horizontal lines • Crosshatching • Branching grooves

42. Use of some type of body metrics for the purpose of identification. (The Bertillon system may actually have been the first biometry system.) Used today in conjunction with AFIS. Examples include retinal or iris patterns, voice recognition, hand geometry. Other functions for biometrics: can be used to control entry or access to computers or other structures; can identify a person for security purposes; can help prevent identity theft or control social services fraud. Biometrics