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11/16/16 Chapter 6 Fingerprints By the end of this chapter you will be able to: x l Vocabulary… Fill in from page 133 All rights Reserved South-Western / Cengage Learning © 2009 1 Forensic Science: Fundamentals & Investigations, Chapter 1 All Rights Reserved South-Western / Cengage Learning © 2009 2 Forensic Science: Fundamentals & Investigations, Chapter 6 Chapter 6 Fingerprints Chapter 6 Fingerprints By the end of this chapter you will be able to: By the end of this chapter you will be able to: l determine the reliability of fingerprints as a means of l discuss the history of fingerprinting identification l describe the characteristics of fingerprints and l describe the Integrated Automated Fingerprint fingerprinting minutiae Identification System (IFAIS) l explain when and how fingerprints are formed l explain how fingerprint evidence is collected l describe the latest identification technologies l determine if a fingerprint matches a fingerprint on l describe what causes fingerprints to be left on objects l identify the basic types of fingerprints record l describe how criminals attempt to alter their fingerprints l use the process of lifting a latent print All Rights Reserved South-Western / Cengage Learning © 2009 3 Forensic Science: Fundamentals & Investigations, Chapter 6 4 Unaltered Identity Forensic Science: Fundamentals & Investigations, Chapter 6 Historical Development l Groups of 3 / Read p. 132 l The oldest known documents showing fingerprints date from third century B.C. China. l In ancient Babylon (dating back to 1792-1750 B.C.), fingerprints pressed into clay tablets marked contracts. l The earliest written study (1684) is Dr. Nehemiah’s paper describing the patterns he saw on human hands under a microscope, including the presence of ridges. l In 1788, Johann Mayer noted that the arrangement of skin ridges is never duplicated in two persons. He was probably the first scientist to recognize this fact. l Piece of Paper / Everyone’s Name / To Hand In 1. What movies have you seen that depicted 5 criminals and the crimes they committed? 2. Were these criminals caught in the movies? 3. What evidence did the police have that was key to putting the criminals behind bars? 4. In the movies how do criminals try to hide their fingerprints? Forensic Science: Fundamentals & Investigations, Chapter 6 6 Forensic Science: Fundamentals & Investigations, Chapter 6 1 11/16/16 Historical Development l Nine fingerprint patterns were described in 1823 by Jan Evangelist Purkyn. l Sir William Herschel (shown at the right), in 1856, began the collection of fingerprints and noted they were not altered by age. l Alphonse Bertillon created a way to identify criminals that was used in 1883 to identify a repeat offender. In 1888, Sir Francis Galton (shown at the right), and Sir Edmund Richard Henry, developed the fingerprint classification system that is still in use in the United States. l 7 Forensic Science: Fundamentals & Investigations, Chapter 6 Historical Development 8 l Beginning in 1896, Sir Henry (mentioned in the last entry on the previous slide), with the help of two colleagues, created a system that divided fingerprints into groups. Along with notations about individual characteristics, all ten fingerprints were imprinted on a card (called a ten card). Forensic Science: Fundamentals & Investigations, Chapter 6 What Are Fingerprints? l All fingers, toes, feet, and palms are l These ridges help us get or keep our grip on objects. l These ridges are arranged in connected l Natural secretions plus dirt on these units called dermal, or friction, ridges. 11 In 1891, Iván (Juan) Vucetich improved fingerprint collection. He began to note measurements on identification cards, as well as adding all ten fingerprint impressions. He also invented a better way of collecting the impressions. What Are Fingerprints? covered in small ridges. 9 l Forensic Science: Fundamentals & Investigations, Chapter 6 surfaces leave behind an impression (a print) on those objects with which we come in contact. 10 Forensic Science: Fundamentals & Investigations, Chapter 6 Formation of Fingerprints Formation of Fingerprints l An animal’s external tissue (skin) consists l Fingerprints probably begin forming at the of (a) an inner dermis and (b) an outer epidermis. l The creation of fingerprints occurs in a special layer (the basal layer) in the epidermis where new skin cells are produced. start of the 10th week of pregnancy. l Because the basal layer grows faster than the others, it collapses, forming intricate shapes. Forensic Science: Fundamentals & Investigations, Chapter 6 12 Forensic Science: Fundamentals & Investigations, Chapter 6 2 11/16/16 Characteristics of Fingerprints Characteristics of Fingerprints l There are 3 general fingerprint distinctions: l Forensic examiners look for the presence of ARCH About 5% of the population 13 WHORL LOOP About 30% of the population About 65% of the population Forensic Science: Fundamentals & Investigations, Chapter 6 a core (the center of a whorl or loop) and deltas (triangular regions near a loop). 14 Characteristics of Fingerprints Characteristics of Fingerprints l A ridge count is another characteristic that l Basic patterns can be further divided: – Arch patterns can be plain (4%) or tented (1%). – Whorl patterns can be central pocket (2%), double loop (4%), or accidental (0.01%). distinguishes one fingerprint from another. The count is made from the center of the core to the edge of the delta. 15 Forensic Science: Fundamentals & Investigations, Chapter 6 16 Forensic Science: Fundamentals & Investigations, Chapter 6 Characteristics of Fingerprints Types of Fingerprints l Even twins have unique fingerprints There are 3 types of prints that investigators look for at crime scenes: due to small differences (called minutiae) in the ridge patterns. 17 Forensic Science: Fundamentals & Investigations, Chapter 6 Forensic Science: Fundamentals & Investigations, Chapter 6 1. Patent fingerprints are visible prints transferred onto smooth surfaces by blood or other liquids. 18 Forensic Science: Fundamentals & Investigations, Chapter 6 3 11/16/16 19 Types of Fingerprints Types of Fingerprints 2. Plastic fingerprints are indentations left in soft materials such as clay or wax. 3. Latent fingerprints are not visible but made so by dusting with powders or the use of chemicals. Forensic Science: Fundamentals & Investigations, Chapter 6 20 Ridge Characteristics l § § § § § § § § § § 21 Comparison Minutiae—characteristics of ridge patterns Ridge ending Short ridge Dot or fragment Bifurcation Double bifurcation Trifurcation Bridge Island Enclosure Spur Forensic Science: Fundamentals & Investigations, Chapter 6 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. 22 Forensic Science: Fundamentals & Investigations, Chapter 6 Fingerprint Forensic FAQs Fingerprint Forensic FAQs l Can fingerprints be erased? l Is fingerprint identification reliable? No, if, for example, they are removed with chemicals, they will grow back. 23 Forensic Science: Fundamentals & Investigations, Chapter 6 Forensic Science: Fundamentals & Investigations, Chapter 6 Yes, but analysts can make mistakes. 24 Forensic Science: Fundamentals & Investigations, Chapter 6 4 11/16/16 Fingerprint Forensic FAQs AFIS l 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. 25 Forensic Science: Fundamentals & Investigations, Chapter 6 § § § 26 § 27 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 Forensic Science: Fundamentals & Investigations, Chapter 6 How are latent fingerprints collected? AFIS § The Automated Fingerprint Identification System - a computer system for storing and retrieving fingerprints Began in the early 1970’s to: 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 Forensic Science: Fundamentals & Investigations, Chapter 6 28 Forensic Science: Fundamentals & Investigations, Chapter 6 The Future of Fingerprinting l New scanning technologies and digitally identifying patterns may eliminate analytical mistakes. l Trace elements of objects that have been touched are being studied to help with the identification of individuals. l To help with identification, other physical features such as eyes and facial patterns are also being studied. 29 Forensic Science: Fundamentals & Investigations, Chapter 6 5