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Fingerprints

Fingerprints. Chapter 14 Criminalistics. History of Fingerprinting. Alphonse Bertillon in 1883 First systematic attempt at personal identification Anthropometry : system of precise body measurements. Included detailed descriptions of the subject

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Fingerprints

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  1. Fingerprints Chapter 14 Criminalistics

  2. History of Fingerprinting • Alphonse Bertillon in 1883 • First systematic attempt at personal identification • Anthropometry: system of precise body measurements. • Included detailed descriptions of the subject • Believed that dimensions of the human bone system remained fixed from the age of 20 until death. • Full-length and profile photographs • Problems? Accuracy of measurements were disproved by the William West Case

  3. William Herschel • Required natives in India to sign contracts with the imprint of their right hand • Not sure if he noticed the differences in prints or was practicing a Hindu custom • Did not publish any ideas until after Fauld

  4. Henry Fauld (1880) • Suggested skin ridge patterns were important for identification of criminals

  5. History of Fingerprinting • Francis Galton • 1892: Published Finger Prints • Described the anatomy of fingerprints and suggested methods for recording them • Acknowledged that no two prints are alike and do not change throughout a lifetime • Three pattern types • Loops, Arches, and Whorls

  6. Dr. Juan Vucetich • Argentinian police officer • First to devise a classification system for fingerprints • Although modified, still widely used in Spanish-speaking countries

  7. Sir Edmund Richard Henry • Proposed another classification system in 1897 • Most English-speaking countries use some form of this system to this day

  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 • Ridge Characteristics: The combination of details in the shapes and positions of ridges in fingerprints that make each unique; also called minutiae. • Examples: bifurcation, enclosures, islands, ridge endings, short ridges, ridge crossings, deltas

  9. Minutiae: Double Bifurcation Island ridge (or short ridge) Spur (or hook) Trifurcation Eye (enclosure or island) Dot (or very short ridge)

  10. Figure 14-1

  11. Figure 14-2

  12. Fundamental Principles of Fingerprints • Second Principle • A Fingerprint remains unchanged during an individual’s lifetime • Formation of fingerprints: • Developed during fetal development • Hills (Ridges): raised portions of the epidermis • Valleys (Grooves): lowered portions of the epidermis • IT IS THE RIDGES THAT ARE INKED WHEN FINGERPRINTS ARE TAKEN

  13. The three layers that compose skin are epidermis (outer layer), dermis (inner layer) and the shape of the dermal papillae which determine the form and pattern of the ridges at the surface of the skin.

  14. It is impossible to change one’s fingerprint even though there have been numerous attempts. • Serious injury can leave permanent scar. But it must penetrate 1 to 2 millimeters beneath the skin’s surface. • Must damage the dermis

  15. John Dillinger • Tried to destroy fingerprints by using corrosive acid • Prints taken at the morgue after his death were compared to prints taken from an earlier arrest showed that prints were unchanged and his efforts useless.

  16. John Dillinger- before acid

  17. John Dillinger prints- after acid

  18. “Smiling Gus” Winkler • Famous criminal of the 1920’s • Had a strip down the center of his fingerprint surgically removed • Efforts did not completely destroy ridge patterns

  19. Before and After

  20. Fundamental Principles of Fingerprints • Third Principle • Fingerprints have general ridge patterns that permit them to systematically classified.

  21. Three Classes of Fingerprints • Loops, Whorls, and Arches • Loops: 65% of world’s population • Whorls: 30-35% of world’s population • Arches: 5% of world’s population

  22. Loops

  23. Whorls

  24. Arches

  25. Loop Patterns • One or more ridges entering from one side of the print, recurving, and exiting from the same side

  26. Types of Loop Patterns • Ulnar Loop: loop opens toward little finger • Radial Loop: loop opens toward the thumb • Type Lines: pattern area of the loop surrounded by two diverging ridges • Delta: the point directly in front of the diverging ridges—loops MUST have at least one delta • Core: the center of pattern

  27. Types of Whorl Patterns • Four types of patterns • Plain Whorl • Central Pocket Loop Whorl • Double Loop Whorl • Accidental Whorl All whorl patterns must have type lines and a MINIMUM of two deltas.

  28. Types of Whorl Patterns • Plain and Central Pocket Loops • Plain whorl and central pocket loops have AT LEAST one ridge that makes a complete circuit • Ridge may be a spiral, oval, or any variant of a circle

  29. Types of Whorl Patterns • Plain Whorl: an imaginary line is drawn between TWO deltas and the spiral is crossed • Central Pocket Loop: spiral is not crossed when imaginary line is drawn

  30. Types of Whorl Patterns • Double Loop: has two loops in one fingerprint • Accidental Loop: has two or more patterns or is not classified into any other category

  31. Types of Whorl Patterns Figure 14-6

  32. Arch Patterns • Plain arch: ridges entering one side of the fingerprint and exiting the other side • Tented arch: this pattern risessharply in the center

  33. Arch Patterns Figure 14-7

  34. Classification of Fingerprints • The original Henry System converted ridge patterns on all 10 fingers into a series of numbers and letters arranged in the form of a fraction. • Problem: It could only classify fingerprints up to 100,000 sets of prints so as collections grew, it became necessary to expand the capacity of the classification system.

  35. FBI System • In the US, the FBI expanded the classification capacity and these modifications are collectively known as the FBI System.

  36. Using the FBI System, all fingerprint cards can be divided into 1,024 groups.

  37. How the FBI System Works • The following sequence can be used to classify fingerprints: R. IndexR. RingL. ThumbL. MiddleL. Little1 R. Thumb R. Middle R. Little L. Index L. Ring 1 16 8 4 2 0 Whorl Values Zeros are assigned for loops and arches Fraction gives individualized result for each person + + + + +

  38. The presence or absence of the whorl pattern is the basis for 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, a value of 8.

  39. On the third pair, a value of 4. • On the fourth pair, a value of 2. • On the last pair, a value of 1. • Any finger with an arch or loop patterns is assigned a value of 0.

  40. Once all values are obtained, then 1/1 is added to the numerator and denominator. • A fingerprint classification system cannot identify an individual, rather it provides a number of candidates that have similarities with the known set of prints. • The identification must always be made by a final visual comparison of the suspects print’s and the file print’s ridge characteristics.

  41. Problems with FBI System • 25% of population falls into the 1/1 category • Only useful when all 10 prints are available • Cumbersome and Time Consuming to look through cards • Often only one or two prints found at a crime scene

  42. AFIS • Automated Fingerprint Identification System • Computer-scans and digitally encodes fingerprints based on minutiae of ridge endings and bifurications • List of prints is generated then a fingerprint examiner confirms match

  43. Benefits of AFIS • Computer can make thousands of accurate fingerprint comparisons in a second • Can filter out imperfections in latent prints found at a crime scene • Suspect lists are generated faster and investigators can spend more time focusing on suspects

  44. A Typical AFIS Matching Screen

  45. IAFIS • Integrated Automated Fingerprint System • Largest AFIS in the United States • Contains nearly 50 million fingerprint records

  46. What is included in IAFIS: • Not only fingerprints, but corresponding criminal histories; mug shots; scars and tattoo photos; physical characteristics like height, weight, and hair and eye color; and aliases. • The system also includes civil fingerprints, mostly of individuals who have served or are serving in the U.S. military or have been or are employed by the federal government. • The fingerprints and criminal history information are submitted voluntarily by state, local, and federal law enforcement agencies.

  47. Types of Crime Scene Prints • Three Types: • Visible Prints • Plastic Prints • Latent (Invisible) Prints

  48. Visible Prints • Can be seen with the naked eye • Made by fingers touching a surface after ridges have been in contact with a colored material such as blood, paint, grease, ink, etc.

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