1. Chapter 4: Fingerprints
“Fingerprints can not lie,
but liars can make fingerprints.”
—Unknown
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2. Kendall/Hunt Publishing Company
Chapter 4
Fingerprints
Students will learn:
Why fingerprints are individual evidence.
Why there may be no fingerprint evidence at a crime scene.
How computers have made personal identification easier.
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3. Students will be able to:
Chapter 4
Fingerprints
Students will be able to:
Define the 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.
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4. Fundamental Principles of Fingerprints
Chapter 4
Fundamental Principles of Fingerprints
A fingerprint is an individual characteristic.
Fingerprints will remain unchanged during an individual’s lifetime.
Fingerprints have general characteristic ridge patterns that permit them to be systematically classified.
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5. History of Fingerprints
Chapter 4
History of Fingerprints
Dactyloscopy is the study of fingerprints.
Early Contributions came from:
William Herschel (1877)—required Indians to put their fingerprints on contracts: also used them to identify prisoners
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6. History of Fingerprints
Chapter 4
History of Fingerprints
Henry Faulds (1880)—claimed that fingerprints did not change over time and that they could be classified for identification: used an ink and transfer method to record prints.
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7. History of Fingerprints
Chapter 4
History of Fingerprints
Alphonse Bertillon (1881)—proposed body measurements as a means of identification (anthropometry)
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8. History of Fingerprints
Chapter 4
History of Fingerprints
Francis Galton (1891)—developed a classification scheme based on loops, arches and whorls: also, showed that no two prints are alike and that they can not be altered.
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9. History of Fingerprints
Chapter 4
History of Fingerprints
Edward Richard Henry (1897)—worked with Galton to institute a numerical classification system which is currently used in most English-speaking countries
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10. History of Fingerprints
Chapter 4
History of Fingerprints
Juan Vucetich (1901)—developed a similar classification system for Spanish-speaking countries
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11. History of Fingerprints
Chapter 4
History of Fingerprints
The Identification Division of the FBI was formed in 1924.
Currently, FBI has 250 million sets of fingerprints records
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12. Anatomy of Fingerprints
Chapter 4
Anatomy of Fingerprints
The ridges and grooves of fingerprints are known as friction ridges
Unique to each person
Also found on palms, feet, and lips
Not genetically controlled, so even identical twins will have different fingerprints
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13. Anatomy of Fingerprints
Chapter 4
Anatomy of Fingerprints
The friction ridge on the epidermis is determined by a lower layer known as the papillae
Chemically or physically altering the epidermis only causes pain because the original print will soon grow back.
Fingerprint residue is made up of salt, complex organic compounds and body oil. Residue of most prints is about 1 microgram (one-millionth of a gram)
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14. Classification of Fingerprints
Chapter 4
Classification of Fingerprints
All fingerprints can be classified into three basic patterns:
Loops (65% of all fingerprints)
Whorls (20 % of all fingerprints)
Arches (least common)
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15. Kendall/Hunt Publishing Company
Chapter 4
Loop
Core
A loop must have one or more ridges entering and exiting from the same side. Loops must have one delta (triangular area) and a core
Two Types
Radial —opens toward the thumb
Ulnar —opens toward the “pinky” (more common)
Which type of loop is this, if it is on the right hand? Left hand? (If you do not know which hand left the print, you can not determine type)
Delta Ridge
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Chapter 4
Whorl
Core
Whorls: subdivided into 4 groups:
Types
Plain
Central Pocket
Double Loop
Accidental
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.
Delta Delta
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Chapter 4
Arch
An arch is the least common and simplest pattern. Arches have no delta or core. All ridges enter one side and exit the other.
Types
Plain
Tented
Plain Arch
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18. All Eight Fingerprint Types
Chapter 4
All Eight Fingerprint Types
Prints are from the right hand
Whorl
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19. Primary Classification
Chapter 4
Primary Classification
In the The Henry—FBI Classification (Developed by Edward Henry)
each finger is given a point value
right
left
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20. Primary Classification
Chapter 4
Primary Classification
Assign the number of points for each finger that has a whorl and substitute into the equation (one is added to the numerator and denominator to avoid having zeros in the classification):
right right left left left
index ring thumb middle little =
right right right left left
thumb middle little index ring
That number is your primary classification number
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21. Primary Classification
The primary classification number is used to narrow a search.
This method (The Primary Henry-FBI Classification) allows all sets of ten fingerprints to be divided into 1,024 groups.
The frequency of loops, whorls and arches present in the general population has been determined.
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Frequency of Patterns
Example: About 25% of people have no whorls—so a primary classification of 1/1 is quite common.
The chart below shows the frequency of fingerprint patterns in the general population
Loops
Whorls
Arches
Ulnar Radial
Plain Other
Plain Tented
60% 5%
20%
10% 4% 1%
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23. Kendall/Hunt Publishing Company
Ridge Classification
After primary classification, scientists must then use the fine structure of ridge characteristics called minutiae to individualize them.
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24. Ridge Characteristics
Chapter 4
Ridge Characteristics
Minutiae —ten different patterns are used
Ridge ending
Short ridge
Dot or fragment
Bifurcation
Double bifurcation
Trifurcation
Bridge
Island
Enclosure
Spur
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25. Kendall/Hunt Publishing Company
Chapter 4
Fingerprint Minutiae
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26. Kendall/Hunt Publishing Company
Chapter 4
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.
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Types of Prints
Plastic prints :(aka. indented or molded prints): prints transferred into materials such as fresh paint, putty, soap, wax, gum, envelopes, stamps, even a softened candy bar.
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Types of Prints
Visible prints: left by a finger that has touched colored material such as blood, paint, ink, grease, chalk, mud, or dust.
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29. Kendall/Hunt Publishing Company Kendall/Hunt Publishing Company
Chapter 4
Types of 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.
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30. Kendall/Hunt Publishing Company
Chapter 4
Latent Prints
Most secretions come from three glands:
Eccrine —largely water with both inorganic (ammonia, chlorides, metal ions, phosphates) and organic compounds (amino acids, lactic acids, urea, sugars). Most important for fingerprints.
Apocrine —secrete pheromones and other organic materials.
Sebaceous —secrete fatty or greasy substances.
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31. Developing Latent Prints
Chapter 4
Developing Latent Prints
Developing a print requires substances that interact with secretions that cause 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.
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32. Developing Latent Prints
Chapter 4
Developing Latent Prints
Powders —adhere to both water and fatty deposits. They can be used on hard, nonporous surfaces. Choose a color to contrast the background. Prints can then be “lifted” with sticky tape.
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33. Developing Latent Prints
Various chemical methods can be used to visualize prints on porous surfaces such as paper, styrofoam and leather.
Iodine —fumes react with oils and fats to produce a temporary yellow brown reaction.
Iodine print
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34. Developing Latent Prints
Ninhydrin —reacts with amino acids to produce a purple color.
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35. Developing Latent Prints
Silver nitrate —reacts with salt from sweat to form silver chloride, a material which turns gray when exposed to light.
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36. Kendall/Hunt Publishing Company Kendall/Hunt Publishing Company
Chapter 4
Super glue fuming
Cyanoacrylate—“super glue” fumes react with water and other fingerprint constituents to form a hard, whitish deposit. It can be used for prints on metals, glass, and plastics.
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37. Kendall/Hunt Publishing Company
Order is Important
Always do the least damaging test first:
Iodine fuming
Ninhydrin
Silver nitrate—last because it will wash away traces of fatty oils and proteins
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38. Developing Latent Prints
Chapter 4
Developing Latent Prints
In modern labs, lasers and alternative light sources are used to view latent fingerprints.
These were first used by the FBI in Since lasers can damage the retina of the eye, special precautions must be taken.
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39. Kendall/Hunt Publishing Company
Chapter 4
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
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40. Kendall/Hunt Publishing Company Kendall/Hunt Publishing Company
Chapter 4
AFIS
By the 1990’s most large jurisdictions had their own problem - a person’s fingerprints may be in one AFIS but not in others
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41. Kendall/Hunt Publishing Company Kendall/Hunt Publishing Company
Chapter 4
IAFIS
Problems were lessened when the FBI created IAFIS (Integrated Automated Fingerprint Identification System): a national database of all 10 print cards from all over the country.
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42. Kendall/Hunt Publishing Company
Chapter 4
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.
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43. Kendall/Hunt Publishing Company
Chapter 4
Other Prints
Palm—friction ridges can be identified and may be used against suspects.
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44. Kendall/Hunt Publishing Company
Chapter 4
Other Prints
Birth footprints can be used as a means of identification of infants.
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45. Kendall/Hunt Publishing Company
Chapter 4
Other Prints
Lips—display several common patterns
Short vertical lines
Short horizontal lines
Crosshatching
Branching grooves
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46. Kendall/Hunt Publishing Company
Chapter 4
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.
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47. Kendall/Hunt Publishing Company
Chapter 4
Other Prints
The blood vessel patterns in the eye may be unique to individuals. They are used today for various security purposes.
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48. Kendall/Hunt Publishing Company Kendall/Hunt Publishing Company
Chapter 4
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
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Chapter 4
Biometrics
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.
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50. Kendall/Hunt Publishing Company
Chapter 4
More about Prints
For additional information about prints and crime, check out Court TV’s Crime Library
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