Fingerprints
Fingerprints 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. Chapter 4 Kendall/Hunt Publishing Company 2 2
Fingerprints Objectives, continued You will be able to: Define 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. Chapter 4 Kendall/Hunt Publishing Company 3 3
Fingerprints 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 Chapter 4 Kendall/Hunt Publishing Company 4 4
Fingerprints The hills and valleys that make up your skin pattern are unique to you. Even identical twins do not have the same fingerprints. Your friction ridges are controlled by the papillae layer. Chapter 4 5 5
Fingerprints Sweat pores release about 98 or 99 percent water. The other 1 to 2 percent is salt, amino acids, oils, etc. From this 1 percent we are able to retrieve fingerprints. Chapter 4 6 6
Fingerprints Dactylscopy: The study of Fingerprints o Started by William Herschel in India during the 19 th century. o He had required the Indians to sign their business contracts with their thumbprint. o Over time he became fascinated with the different samples and began studying. Chapter 4 Kendall/Hunt Publishing Company 7 7
Fingerprints Anthropometry LIdentifying prisoners has allows been tricky. Branding, tattooed, or had limbs chopped off to identify criminals. LOne method was Anthropometry or the science of human measurement. Chapter 4 Kendall/Hunt Publishing Company 8 8
Fingerprints Anthropometry Chapter 4 Kendall/Hunt Publishing Company 9 9
Fingerprints Fingerprint: An impression of the pattern or ridges on the last joint of a person’s finger. Unique Properties: 1. Characteristic Ridges 2. Consistency over a person’s lifetime 3. Systematic Classification of Fingerprints The FBI IAFIS system has millions of fingerprints on file. https: //www. fbi. gov/aboutus/cjis/fingerprints_biometrics/iafis https: //www. youtube. com/watch? v=Ry 8920 R 7 bxs Chapter 4 10 10
Fingerprints Identifying Fingerprints: 1 st – Note a few characteristics that give away certain types of prints. Double Loops always have an “S” shape in the print Double Loop Chapter 4 11 11
Fingerprints Identifying Fingerprints: 1 st – Note a few characteristics that give away certain types of prints. Plain Whorls contain a circle or a spiral. Double Loop Chapter 4 Plain Whorl 12 12
Fingerprints Identifying Fingerprints: 1 st – Note a few characteristics that give away certain types of prints. Central Pocket Loops always have an “S” shape in the print Double Loop Chapter 4 Plain Whorl Central Pocket Loop 13 13
Fingerprints Identifying Fingerprints: 1 st – Note a few characteristics that give away certain types of prints. Loops have some lines that come in one side, turn aroung, and go out the same side. Loop Chapter 4 14 14
Fingerprints Identifying Fingerprints: 1 st – Note a few characteristics that give away certain types of prints. Loops have some lines that come in one side, turn aroung, and go out the same side. Loop Chapter 4 Plain Arch Tented Arch 15 15
Fingerprints Identifying Fingerprints: 1 st – Note a few characteristics that give away certain types of prints. Loops have some lines that come in one side, turn aroung, and go out the same side. Radial Loop Chapter 4 Ulnar Loop 16 16
Fingerprints Identifying Fingerprints: 2 nd – Procedure for Indentifying Print 1. Are there any “S” shapes – [yes = double loop] 2. Do I see Circles? - [yes = Plain whorl (symmetrical) or Central pocket loop (not symmetrical)] 3. If no S shapes or circles we have an arch or a Loop If the lines turn around and go back = loop If the lines do not turn around - arch Chapter 4 17 17
Fingerprints Primary Classification, continued Assign the number of points for each finger that has a whorl and substitute into the equation: right Index 16 right ring 8 left thumb 4 left middle 2 left little 1 +1 right thumb 16 right middle 8 right little 4 left index 2 left ring 1 +1 = That number is your primary classification number. Chapter 4 Kendall/Hunt Publishing Company 18 18
Fingerprints Must be a Whorl, Central Pocket Loop, or Double Loop Chapter 4 Kendall/Hunt Publishing Company 19 19
Fingerprints Identifying Fingerprints: 1 st – Note a few characteristics that give away certain types of prints. Central Pocket Loops always have an “S” shape in the print Double Loop Chapter 4 Plain Whorl Central Pocket Loop 20 20
Fingerprints Must be a Whorl, Central Pocket Loop, or Double Loop Chapter 4 Kendall/Hunt Publishing Company 21 21
Fingerprints Primary Classification, continued Assign the number of points for each finger that has a whorl and substitute into the equation: right Index 0 right ring 0 left thumb 0 left middle 0 left little 0 +1 right thumb 16 right middle 0 right little 0 left index 0 left ring 0 +1 1 = 17 That number is your primary classification number. Chapter 4 22 22
Fingerprints • Common Fingerprint types and percentages. • Loops are the most common with Arches being the lowest. Chapter 4 Kendall/Hunt Publishing Company 23 23
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Fingerprints Primary Classification, continued LPeople of different ancestry have different average classification values African descent European descent Asian Descent Chapter 4 More Arches More Loops More Whorls 27 27
Fingerprints Fingerprint Minutiae L A whorl, loop, or arch is only a general classification. L To match up a fingerprint to its person of origin, you have to look closer at the print. Chapter 4 Kendall/Hunt Publishing Company 28 28
Fingerprints Types of Minutiae Chapter 4 Kendall/Hunt Publishing Company 29 29
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Fingerprints Fingerprint Minutiae Chapter 4 Kendall/Hunt Publishing Company 32 32
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Fingerprints Dactyloscopy The Study of Fingerprints 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 Chapter 4 Kendall/Hunt Publishing Company 36 36
Fingerprints 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. Chapter 4 Kendall/Hunt Publishing Company 37 37
Fingerprints 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 Chapter 4 Kendall/Hunt Publishing Company 38 38
Fingerprints 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? Chapter 4 Kendall/Hunt Publishing Company 39 39
Fingerprints 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 Chapter 4 Kendall/Hunt Publishing Company 40 40
Fingerprints LOOP Chapter 4 WHORL Kendall/Hunt Publishing Company ARCH 41 41
Fingerprints 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. Chapter 4 Kendall/Hunt Publishing Company 42 42
Fingerprints Visible Prints Let by a finger that has touched colored material such as blood, paint, ink, grease, chalk, mud, or sometimes even dust. Chapter 4 Kendall/Hunt Publishing Company 43 43
Fingerprints Plastic Print • Also known as an indented or molded print. • Will involve leaving an impression in a substance like paint, putty, soap, candle wax, etc. Chapter 4 Kendall/Hunt Publishing Company 44 44
Fingerprints Latent Prints 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. Chapter 4 Kendall/Hunt Publishing Company 45 45
Fingerprints Developing Latent Prints 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. 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. Chapter 4 Kendall/Hunt Publishing Company 46 46
Fingerprints Developing Latent Prints, continued Ninhydrin—reacts with amino acids to produce a purple color. Silver nitrate—reacts with chloride to form silver chloride, a material that turns gray when exposed to light. Cyanoacrylate—“superglue” fumes react with water and other fingerprint constituents to form a hard, whitish deposit. 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. Chapter 4 Kendall/Hunt Publishing Company 47 47
Fingerprints Iodine Fingerprint Chapter 4 Kendall/Hunt Publishing Company 48 48
Fingerprints Ninhydrin Fingerprint Chapter 4 Kendall/Hunt Publishing Company 49 49
Fingerprints Cyanoacrylate Fingerprints Chapter 4 Kendall/Hunt Publishing Company 50 50
Fingerprints Cyanoacrylate Fingerprints Chapter 4 Kendall/Hunt Publishing Company 51 51
Fingerprints Other Prints 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 Chapter 4 Kendall/Hunt Publishing Company 52 52
Fingerprints Other Prints, continued Palm—friction ridges can be identified and may be used against suspects Chapter 4 Kendall/Hunt Publishing Company 53 53
Fingerprints Other Prints, continued Footprints are taken at birth as a means of identification of infants. Chapter 4 Kendall/Hunt Publishing Company 54 54
Fingerprints Other Prints, continued Earprint catches murderer 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. Chapter 4 Kendall/Hunt Publishing Company 55 55
Fingerprints 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. Chapter 4 Kendall/Hunt Publishing Company 56 56
Fingerprints Other Prints, continued The blood vessel patterns in the eye may be unique to individuals. They are used today for various security purposes. Chapter 4 Kendall/Hunt Publishing Company 57 57
Fingerprints AFIS The Automated Fingerprint Identification System—a computer system for storing and retrieving fingerprints Established in the 1970 s, 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 1990 s, 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 Chapter 4 Kendall/Hunt Publishing Company 58 58
Fingerprints 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. Chapter 4 Kendall/Hunt Publishing Company 59 59
Fingerprints More about Prints For additional information about prints and crime, check out tru. TV’s Crime Library: www. crimelibrary. com/criminal_mind/forensics/fingerprints/1. html Chapter 4 Kendall/Hunt Publishing Company 60 60
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