Chapter 4 Fingerprints Kendall/Hunt

Fundamental Principles of Fingerprints Chapter 4 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. Kendall/Hunt Publishing Company Kendall/Hunt

Kendall/Hunt Publishing Company All fingers, toes, feet, and palms are covered in small ridges. These ridges are arranged in connected units called dermal, or friction, ridges. These ridges help us get or keep our grip on objects. Natural secretions plus dirt on these surfaces leave behind an impression (a print) on those objects with which we come in contact. Kendall/Hunt Publishing Company

Kendall/Hunt Publishing Company There are 3 main fingerprint patterns found in the human population: Loops: found in 60% of the population Whorls: found in 30% of the population Arches: found in 10% of the population A typical loop must have one or more ridges that enter from one side, loop, and then exit from the same side. Kendall/Hunt Publishing Company

October 4, 2011: Activity – page 77 # 1 Look at your fingerprints under the magnifying glass. Draw each of your prints in the boxes on the worksheet. Figure out whether they have arches, whirls, or loops. Kendall/Hunt Publishing Company

Fingerprint Analysis – page 77 - # 2 Inkprint all of your fingerprints Students work in groups of four: Compare your fingerprints to the other people in your group 1. What were some similarities in your group? 2. What were some differences in your group? 3. What are some problems you can foresee when using fingerprints to identify people? 4. What are some questions you have that you want answered by the end of this unit? Kendall/Hunt Publishing Company

Kendall/Hunt Publishing Company Chapter 4 AFIS The Automated Fingerprint Identification System—a computer system for storing and retrieving fingerprints Established in the 1970s IAFIS—the FBI’s Integrated Automated Fingerprint Identification System, which is a national database of all 10-print cards from all over the country Kendall/Hunt Publishing Company Kendall/Hunt

Kendall/Hunt Publishing Company Chapter 4 Fingerprint Minutiae Kendall/Hunt Publishing Company Kendall/Hunt

Kendall/Hunt Publishing Company Chapter 4 LOOP WHORL ARCH Kendall/Hunt Publishing Company Kendall/Hunt

Kendall/Hunt Publishing Company Chapter 4 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 Kendall/Hunt Publishing Company Kendall/Hunt

Kendall/Hunt Publishing Company Chapter 4 Loop A loop must have one or more ridges entering and exiting from the same side. Loops must have one delta. A double loop is made of two loops. Types Radial—opens toward the thumb Ulnar—opens toward the “pinky” (little finger) Kendall/Hunt Publishing Company Kendall/Hunt

Kendall/Hunt Publishing Company Chapter 4 Whorl A plain or central pocket whorl has at least one ridge that makes a complete circuit. 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 Kendall/Hunt Publishing Company Kendall/Hunt

Primary Classification Chapter 4 Primary Classification The Henry-FBI Classification System Each finger is given a point value. right left Kendall/Hunt Publishing Company Kendall/Hunt

Primary Classification, continued Chapter 4 Primary Classification, continued Assign the number of points for each finger that has a whorl and substitute into the equation: right right left left left index ring thumb middle little + 1 = right right right left left thumb middle little index ring + 1 That total number is your primary classification number. Kendall/Hunt Publishing Company Kendall/Hunt

Kendall/Hunt Publishing Company Chapter 4 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. Kendall/Hunt Publishing Company Kendall/Hunt

Kendall/Hunt Publishing Company Chapter 4 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. Kendall/Hunt Publishing Company Kendall/Hunt

Developing Latent Prints Chapter 4 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. Ninhydrin—reacts with amino acids to produce a purple color. Kendall/Hunt Publishing Company Kendall/Hunt

Kendall/Hunt Publishing Company Chapter 4 Iodine Fingerprint Kendall/Hunt Publishing Company Kendall/Hunt

Kendall/Hunt Publishing Company Chapter 4 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 Kendall/Hunt Publishing Company Kendall/Hunt

Other Prints, continued Chapter 4 Other Prints, continued Palm—friction ridges can be identified and may be used against suspects Kendall/Hunt Publishing Company Kendall/Hunt

Other Prints, continued Chapter 4 Other Prints, continued Footprints are taken at birth as a means of identification of infants. Kendall/Hunt Publishing Company Kendall/Hunt

Other Prints, continued Chapter 4 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. Kendall/Hunt Publishing Company Kendall/Hunt

Other Prints, continued Chapter 4 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. Kendall/Hunt Publishing Company Kendall/Hunt