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Forensics of Fingerprints “commonly used forensic evidence worldwide”

A fingerprint is a unique impression made by the ridges on the ends of fingers and thumbs. Fingerprints provide infallible personal identification as they remain unchanged with growth or age. This article explores the history, classification, and techniques of fingerprinting, as well as its significance in forensic investigations.

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Forensics of Fingerprints “commonly used forensic evidence worldwide”

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  1. Forensics of Fingerprints“commonly used forensic evidence worldwide”

  2. A fingerprint is the impression made by the papillary ridges on the ends of the fingers and thumbs. • Fingerprints afford an infallible means of personal identification, because the ridge arrangement on every finger of every human being is unique and does not alter with growth or age.

  3. Hand or Foot? • Any ridged area of the hand or foot may be used as identification. • Finger impressions are preferred to those from other parts of the body because they can be taken with a minimum of time and effort

  4. Ridges • Each ridge of the epidermis (outer skin) is dotted with sweat pores for its entire length and is anchored to the dermis (inner skin) by a double row of peglike protuberances, or papillae. • Injuries such as superficial burns, abrasions, or cuts do not affect the ridge structure or alter the dermal papillae, and the original pattern is duplicated in any new skin that grows. • An injury that destroys the dermal papillae, however, will permanently obliterate the ridges.

  5. History of Fingerprinting • Prehistoric • Picture writing of a hand with ridge patterns was discovered in Nova Scotia. • In ancient Babylon, fingerprints were used on clay tablets for business transactions. • In ancient China, thumb prints were found on clay seals. • In 14th century Persia, various official government papers had fingerprints (impressions), and one government official, a doctor, observed that no two fingerprints were exactly alike

  6. In earlier civilizations, branding and even maiming were used to mark the criminal for what he was. • The thief was deprived of the hand which committed the thievery.

  7. History of Fingerprinting • Early anatomists described the ridges of the fingers • But interest in modern fingerprint identification dates from 1880, when the British scientific journal Nature published letters describing the uniqueness and permanence of fingerprints.

  8. History of Fingerprinting • Their observations were experimentally verified by the English scientist Sir Francis Galton, who suggested • the first elementary system for classifying fingerprints based on grouping the patterns into arches, loops, and whorls.

  9. History of Fingerprints • The Galton-Henry system of fingerprint classification, published in June 1900, was officially introduced at Scotland Yard in 1901 • It quickly became the basis for its criminal-identification records. • The system was adopted immediately by law-enforcement agencies in the English-speaking countries of the world and is now the most widely used method of fingerprint classification.

  10. Fingerprint Classification • Fingerprints are classified in a three-way process: • by the shapes and contours of individual patterns, • by noting the finger positions of the pattern types, • by relative size, determined by counting the ridges in loops and by tracing the ridges in whorls.

  11. FBI and Fingerprints • Federal Bureau of Investigation (FBI) in the United States recognizes eight different types of patterns: • radial loop • ulnar loop • double loop • central pocket loop • plain arch • tented arch • plain whorl • accidental

  12. Dactyloscopy • is the technique of fingerprinting, involves cleaning the fingers in benzene or ether, • drying them, • then rolling the balls of each over a glass surface coated with printer's ink. • Each finger is then carefully rolled on prepared cards according to an exact technique designed to obtain a light gray impression with clear spaces showing between each ridge so that the ridges may be counted and traced. • Simultaneous impressions are also taken of all fingers and thumbs.

  13. Latent Fingerprinting • involves locating, preserving, and identifying impressions left by a culprit in the course of committing a crime. • In latent fingerprints, the ridge structure is reproduced not in ink on a record card but on an object in sweat, oily secretions, or other substances naturally present on the culprit's fingers. • Most latent prints are colourless and must therefore be "developed," or made visible, before they can be preserved and compared. • This is done by brushing them with various gray or black powders containing chalk or lampblack combined with other agents. • The latent impressions are preserved as evidence either by photography or by lifting powdered prints on the adhesive surfaces of tape.

  14. The UnitedStates • fingerprinting was developed to great usefulness in the United States, • 1924 two large fingerprint collections were consolidated to form the nucleus of the present file maintained by the Identification Division of the FBI. • The division's file contained the fingerprints of more than 90 million persons by the late 20th century. • Fingerprint files and search techniques have been computerized to enable much quicker comparison and identification of particular prints.

  15. . There are at least 150 individual ridge characteristics on the average fingerprint. If between 10 and 16 specific points of reference for any two corresponding fingerprints identically compare, a match is assumed.

  16. Fingerprints in the Population • Loops constitute about 65 percent of the total fingerprint patterns; • whorls make up about 30 percent • arches and tented arches together account for the other 5 percent. • The most common pattern is the ulnar loop.

  17. Three Kinds of CRIME-SCENEPrints • There are actually three kinds of CRIME-SCENE prints. These are: • 1. VISIBLE PRINTS which are prints made by fingers touching a surface after the ridges have been in contact with a colored material such as blood, paint, grease, or ink. • 2. PLASTIC PRINTS which are ridge impressions left on a soft material such as putty, wax, soap, or dust. • 3. True LATENT PRINTS which are invisible print impressions caused by the perspiration on the ridges of one’s skin coming in contact with a surface and making an invisible impression on it. Perspiration contains water, salt, amino acids, or oils and easily allows impressions to be made.

  18. The most common techniques used to find latent or hidden fingerprints • 1. Dusting with Carbon Powder on white or light colored surfaces. • 2. Dusting with Lanconide Powder for black surfaces. • 3. Dusting with Aluminum Powder for hard or dark colored surfaces as well as mirrors and metal surfaces. • 4. Use of Cyanoacrylate (Super-glue) fuming. • 5. Use of Iodine fuming techniques. • 6. Use of ninhydrin. • 7. Use of Silver Nitrate. • 8. Use of Gentian violet. • 9. Use of Laser technology.

  19. Tools • A number of portable fingerprint scanners were developed mainly by computer companies to provide a secure access for the users. • In 1998, Compaq was the first to have a print reader attached to the computer

  20. Tools • Some companies, police offices, and high-security government buildings require fingerprint identification for access to the building or its selected parts. • In order to protect sensitive data, some businesses and the military often use scanners that are attached to computers (the U-Match mouse, for example) or installed in keyboards. These provide either immediate identification for access to the terminal or remote identification for access to secure documents or archives.

  21. Tools • New scanner trials are on the way to provide the same protection for e-commerce and Internet banking in order to secure transactions. • In order to combat cell phone thefts, the industry is considering equipping phones with fingerprint readers.

  22. Five U.S. airports, including Chicago's O'Hare have installed finger-print scanners to check employees' backgrounds. • Some banks use fingerprint scans before a check is cashed. • Similarly, government agencies sometimes utilize fingerprint scans to ensure that payments are given to the proper recipients.

  23. Fingerprint Principles According to criminal investigators, fingerprints follow 3 fundamental principles: A fingerprint is an individual characteristic; no two people have been found with the exact same fingerprint pattern. A fingerprint pattern will remain unchanged for the life of an individual; however, the print itself may change due to permanent scars and skin diseases. Fingerprints have general characteristic ridge patterns that allow them to be systematically identified.

  24. Fingerprint Classes There are 3 specific classes for all fingerprints based upon their visual pattern: arches, loops, and whorls. Each group is divided into smaller groups as seen in the lists below. Arch Plain arch Tented arch Loop Radial Loop Ulnar loop Whorl Plain whorl Central pocket whorl Double loop whorl Accidentical

  25. Interesting Info Did you know? Dactyloscopy is the study of fingerprint identification. Police investigators are experts in collecting “dactylograms”, otherwise known as fingerprints. ADD TO NOTES Fingerprint Factoid: 60% of people have loops, 35% have whorls, and 5% have arches

  26. Arches Spike or “tent” Plain Arch Ridges enter on one side and exit on the other side. Tented Arches Similar to the plain arch, but has a spike in the center. Arches are the simplest type of fingerprints that are formed by ridges that enter on one side of the print and exit on the other. No deltas are present.

  27. Loops Loops must have one delta and one or more ridges that enter and leave on the same side. These patterns are named for their positions related to the radius and ulna bones. Delta Ulnar Loop (Right Thumb) Loop opens toward right or the ulna bone. Radial Loop (Right Thumb) Loop opens toward the left or the radial bone. NOTE: On the left hand, a loop that opens to the left would be an ulnar loop, while one that opens to the right would be a radial loop.

  28. Whorls Whorls have at least one ridge that makes (or tends to make) a complete circuit. They also have at least two deltas. If a print has more than two deltas, it is most likely an accidental. Central Pocket Whorl Plain Whorl Draw a line between the two deltas in the plain and central pocket whorls. If some of the curved ridges touch the line, it is a plain whorl. If none of the center core touches the line, it is a central pocket whorl.

  29. Whorls – Part 2 Double Loop Whorl Accidental Whorl Double loop whorls are made up of any two loops combined into one print. Accidental whorls contain two or more patterns (not including the plain arch), or does not clearly fall under any of the other categories. Delta Delta

  30. Identify each fingerprint pattern. ? A B Right Hand Left Hand C Right Hand E D Right Hand Left Hand

  31. Did you know? 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. Ridgeology: The study of the uniqueness of friction ridge structures and their use for personal identification.1 1Introduction to Basic Ridgeology by David Ashbaugh, May 1999 Image from http://www.cs.usyd.edu.au/~irena/minutia.gif

  32. Automated Fingerprint Identification System (AFIS) AFIS is a computerized system capable of reading, classifying, matching, and storing fingerprints for criminal justice agencies. Quality latent fingerprints are entered into the AFIS for a search for possible matches against the state maintained databases for fingerprint records to help establish the identity of unknown deceased persons or suspects in a criminal case. http://www.fdle.state.fl.us/CrimeLab/images/fingerrint%20comparison%20for%20afis.jpg Fingerprint Identification When minutiae on two different prints match, these are called points of similarity or points of identification. At this point there is no international standard for the number of points of identification required for a match between two fingerprints. However, the United Kingdom requires a minimum sixteen points while Australia requires twelve.

  33. Ridge Characteristics Use these characteristics as points of identification when comparing fingerprint samples. The more points you can find in common, the better the match!

  34. Crossover Core Bifurcation (fork) Ridge ending Scar Island Delta Pore Ridge Characteristics EXAMPLE http://cnx.org/content/m12574/latest/properties.jpg

  35. http://www.dkfz.de/tbi/projects/bmcv/images/iu_it246_04s_fingerprint1.jpghttp://www.dkfz.de/tbi/projects/bmcv/images/iu_it246_04s_fingerprint1.jpg How many ridge characteristics can you identify in this fingerprint?

  36. It’s time to makesome prints! Avoid Partial Prints GOOD PRINTGet as much of the top part of your finger as possible!

  37. Try It! 1 – Blow up your balloon about halfway and twist the end to keep the air from coming out. Do not tie it off! 2 – Use an ink pad to make a print with all of your fingers and label each one with a permanent marker. Write your name on the balloon as well. 3 – Blow up the balloon to full size and tie the end. 4 – Analyze the fingerprints to find several ridge structures that we have discussed. Use a highlighter to mark these structures on your “My Prints” worksheet. Think About It! Which ridge structures were most common in your fingerprints? Which ridge structures were most common in your group? Were there any structures that were not found in any of the fingerprints? Balloon Fingerprint Activity: http://www.msichicago.org/fileadmin/Education/learninglabs/lab_downloads/fingerprint_analysis.pdf

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