Chapter 4 — Fingerprints Fingerprint An imprint made

Chapter 4 - Fingerprints Fingerprint An imprint made by ridge patterns on the tip of a finger

Fundamental Principles of Fingerprints § A fingerprint is an individual characteristic. § A fingerprint will remain unchanged during an individual’s lifetime. § Fingerprints have general characteristic ridge patterns that permit them to be systematically classified.

Ridge Characteristics § § § § § Minutiae—characteristics of ridge patterns Ridge ending Short ridge Dot or fragment Bifurcation Double bifurcation Trifurcation Bridge Island Enclosure Spur

Classification of Fingerprints n Loops (60 -70% of prints have loops) n Whorls (25 -35% of prints have whirls) n Arches (least common, 5% of prints have arches)

Loop § A loop must have one or more ridges entering and exiting from the same side. Loops must have one core and one delta. § Types Ø Radial—opens toward the thumb Which type of loop is this? Ø Ulnar—opens toward Is it on the right hand? the “pinky” (little Left hand? finger)

Loop Radial Loop Which hand? One core One delta

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 Ø Plain Ø Central Pocket Ø Double Loop Ø Accidental

Whorl 4 Types Plain The central circular ridge is touched Central Pocket The central circular ridge is NOT touched Double loop 2 distinct loops with 2 distinct shoulders Accidental More than 2 deltas

Whorl What type of Whorl? Central Pocket Plain Double Loop

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 deltas or cores. Types ØPlain ØTented

Arch 2 Types Plain Arch Tented Arch

Frequency of Fingerprint Patterns Loops ulnar 60% Whorls radial plain 5% 20% Arches other plain tented 10% 4% 1%

Primary Classification The Henry—FBI Classification Each finger is given a point value Right Left

Primary Classification Assign the number of points for each finger that has a whorl and substitute into the equation: right left index ring thumb middle little + 1 right left thumb middle little index ring +1 = That number is your primary classification number

It’s time to make some prints! Avoid Partial Prints GOOD PRINT Get as much of the top part of your finger as possible!

Directions 1 st – Roll the “pad” portion of your thumb over the ink pad from the left side of your thumb to the right. You do not have to push down really hard! 2 nd – Roll the “pad” portion of your thumb from the left side of your thumb to the right in the correct box on your paper to make a thumbprint. 3 rd – Continue this process to make a fingerprint of all ten fingers on the “My Prints” worksheet. 4 th –Use your notes and a magnifying lens to help you figure out what type of pattern is found in each of your fingerprints. Label each one with the pattern’s name.

Identify each fingerprint pattern. Left Hand Right Hand Left Hand

Ridge Classification (Individualization) You have learned how to classify fingerprints according to general patterns of groups, but to individualize them, must use the details of the ridge characteristics. Minutiae—characteristics of ridge patterns

Is it a match? n n n There at least 150 individual ridge characteristics on the average fingerprint. If between 10 -16 specific points of reference for any two fingerprints identically compare, a match is assumed. Identify the 12 characteristics on the fingerprint.

Comparison There are no legal requirements in the United States on the number of points. Generally, criminal courts will accept 8 to 12 points of similarity to make a unique ID.

Comparison Core A scar Delta Spur Island Dot Bridge Bifurcation Double bifurcation Ridge ending

Fingerprints and the Law n n In judicial proceedings, comparison must be made for at least 12 different points to be considered a match. Automated Fingerprint Identification System – AFIS - AFIS is a computerized system capable of reading, classifying, matching, and storing fingerprints for criminal justice agencies.

John Dillinger’s Fingerprint Card bli Pu En c my e o. N 1

Find at least 12 fingerprint characteristics n On your own identify as many characteristics as you can The koala is one of the few mammals (other than primates) that has fingerprints. In fact, koala fingerprints are remarkably similar to human fingerprints; even with an electron microscope, it can be quite difficult to distinguish between the two.

Dactyloscopy – The study of fingerprints Historically § William Herschel—required Indians to put their fingerprints on contracts, and also 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 based on Galton’s that is used in Spanish-speaking countries

Will West William West

Types of Prints n Plastic prints (indented or molded) 3 -D print made as indentation in soft material n Visible prints left by finger that has touched blood, paint, ink … n Latent prints made by deposit of perspiration or body oils. Invisible until developed

Latent Prints § § Latent fingerprints are those 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: Ø Eccrine sweat gland—largely water with both inorganic (ammonia, chlorides, metal ions, phosphates) and organic compounds (amino acids, lactic acids, urea, sugars). Most important for fingerprints. ØApocrine—secrete pheromones and other organic materials. ØSebaceous—secrete fatty or greasy substances

Latent Prints Skin sweat pore sweat gland duct Sebaceous gland Epidermis Dermis Eccrine sweat gland Apocrine sweat gland Hair follicle Subcutaneous layer

Developing Latent Prints Developing a print requires substances that interact with secretions that cause the print to stand out against its background. More than one technique may be necessary. Methods to develop latent prints fall in 3 groups - Physical techniques - Chemical techniques - Instrumental techniques 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

Developing Latent Prints: Methods 1. Powders—adhere to both water and fatty deposits. Choose a color to contrast the background: - white powder for dark colored surfaces - black powder for light colored surfaces - Bichromatic (grey) for either light or dark - magnetic powder for rough surfaces Best on hard, nonabsorbant surfaces

Developing Latent Prints: Methods 2. Iodine—fumes react with oils and fats to produce a temporary yellow brown reaction. Best on soft, porous surfaces

Developing Latent Prints: Methods 3. Ninhydrin—reacts with amino acids to produce a purple color. Good for clothing and paper. Best on paper and porous surfaces

Developing Latent Prints: Methods 4. Silver nitrate—reacts with chloride to form silver chloride, a material which turns gray when exposed to light.

Developing Latent Prints: Methods 5. Cyanoacrylate—“super glue” fumes react with water and other fingerprint constituents to form a hard, whitish deposit which becomes permanent. Stains and dyes can be added afterwards to improve visibility. Used on non porous surfaces. Best on nonporous surfaces (glass, metals, tapes …)

Case Files The Night Stalker Richard Ramirez Jack the K nife

Dusting Latent Prints

Other Prints § Ears—shape, length and width § 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 Palm—friction ridges can be identified and may be used against suspects.

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

Other Prints Lips—display several common patterns § Short vertical lines § Short horizontal lines § Crosshatching § Branching grooves

Other Prints 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.

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

AFIS § § The Automated Fingerprint Identification System - a computer system for storing and retrieving fingerprints Began in the early 1970’s 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 1990’s most large jurisdictions had their own system in place. The problem - a person’s fingerprints may be in one AFIS 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

Biometrics § § 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.

Other Prints For additional information about prints and crime, check out Court TV’s Crime Library www. crimelibrary. com/criminal_min d/forensics/fingerprints/1. html

Probability and Statistics is often used in linking evidence to a suspect Example: A suspect was identified walking out of Montville HS carrying one of the missing Forensics textbooks. The suspect was identified as having light brown hair and wearing a green shirt, blue jeans, and dark colored athletic shoes. How common are those characteristics in a school of 1600 students?

Spot the difference, test your memory http: //forensics. rice. edu/html/onlineactivitie s. html

Spot the difference, test your memory http: //forensics. rice. edu/html/onlineactivitie s. html

Dillinger’s Fingerprint card

How observant are you?

Which is the correct penny? NOTE: You cannot look at a real penny! 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

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Demands & Constraints n When and where do we collect? n How do we collect? n For what purpose?