1. Chapter 6 Fingerprints By the end of this chapter you will be able to:
discuss the history of fingerprinting
describe the characteristics of fingerprints and fingerprinting minutiae
explain when and how fingerprints are formed
describe what causes fingerprints to be left on objects
identify the basic types of fingerprints
describe how criminals attempt to alter their fingerprints
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Forensic Science: Fundamentals & Investigations, Chapter 6

2. Chapter 6 Fingerprints By the end of this chapter you will be able to:
determine the reliability of fingerprints as a means of identification
describe the Integrated Automated Fingerprint Identification System (IFAIS)
explain how fingerprint evidence is collected
describe the latest identification technologies
determine if a fingerprint matches a fingerprint on record
use the process of lifting a latent print
Forensic Science: Fundamentals & Investigations, Chapter 6

3. Historical Development
The oldest known documents showing fingerprints date from third century B.C. China.
In ancient Babylon (dating back to B.C.), fingerprints pressed into clay tablets marked contracts.
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.
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.
Forensic Science: Fundamentals & Investigations, Chapter 6

4. Historical Development
5. Nine fingerprint patterns were described in by Jan Evangelist Purkyn.
6. Sir William Herschel (shown at the right), in 1856, began the collection of fingerprints and noted they were not altered by age.
7. Alphonse Bertillon created a way to identify criminals that was used in 1883 to identify a repeat offender.
8. 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.
Forensic Science: Fundamentals & Investigations, Chapter 6

5. Historical Development
9. 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.
10. 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

6. What Are Fingerprints?
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.
Forensic Science: Fundamentals & Investigations, Chapter 6

7. Formation of Fingerprints
An animal’s external tissue (skin) consists of (a) an inner dermis and (b) an outer epidermis.
The creation of fingerprints occurs in a special layer (the basal layer) in the epidermis where new skin cells are produced.
Fingerprints probably begin forming at the start of the 10th week of pregnancy.
Because the basal layer grows faster than the others, it collapses, forming intricate shapes.
Forensic Science: Fundamentals & Investigations, Chapter 6

8. Characteristics of Fingerprints
Forensic examiners look for the presence of a core (the center of a whorl or loop) and deltas (triangular regions near a loop).
A ridge count is another characteristic that distinguishes one fingerprint from another. The count is made from the center of the core to the edge of the delta.
Forensic Science: Fundamentals & Investigations, Chapter 6

9. Ridge Characteristics
Chapter 4
Ridge Characteristics
Minutiae—characteristics of ridge patterns
Ridge ending
Island or
short ridge
Bridge
Eye or enclosure
Delta
Bifurcation or fork
Dot
Spur
Double bifurcation
Trifurcation
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10. Fingerprint Minutiae Chapter 4 Kendall/Hunt
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11. Characteristics of Fingerprints
There are 3 general fingerprint distinctions:
ARCH WHORL LOOP
About 5% About 30% About 65% of the population
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12. 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
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13. Chapter 4
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?
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14. Chapter 4
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
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15. Characteristics of Fingerprints
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%).
Even twins have unique fingerprints due to small differences (called minutiae) in the ridge patterns.
Forensic Science: Fundamentals & Investigations, Chapter 6

16. Types of Fingerprints
There are 3 types of prints that investigators look for at crime scenes:
Patent fingerprints are visible prints transferred onto smooth surfaces by blood or other liquids.
Plastic fingerprints are indentations left in soft materials such as clay or wax.
Latent fingerprints are not visible but made so by dusting with powders or the use of chemicals.
Forensic Science: Fundamentals & Investigations, Chapter 6

17. Fingerprint Forensic FAQs
Can fingerprints be erased?
No, if, for example, they are removed with chemicals, they will grow back.
Is fingerprint identification reliable?
Yes, but analysts can make mistakes.
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.
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18. Fingerprint Forensic FAQs
How are latent fingerprints collected?
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19. Iodine Fingerprint Chapter 4 Kendall/Hunt
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20. Ninhydrin Fingerprint
Chapter 4
Ninhydrin Fingerprint
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21. Cyanoacrylate Fingerprints
Chapter 4
Cyanoacrylate Fingerprints
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22. Other Prints Lips—several common patterns
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
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23. Other Prints, continued
Chapter 4
Other Prints, continued
Palm—friction ridges can be identified and may be used against suspects
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24. Other Prints, continued
Chapter 4
Other Prints, continued
Footprints are taken at birth as a means of identification of infants.
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25. 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.
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26. 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.
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27. Other Prints, continued
Chapter 4
Other Prints, continued
The blood vessel patterns in the eye may be unique to individuals. They are used today for various security purposes.
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28. The Future of Fingerprinting
New scanning technologies and digitally identifying patterns may eliminate analytical mistakes.
Trace elements of objects that have been touched are being studied to help with the identification of individuals.
To help with identification, other physical features such as eyes and facial patterns are also being studied.
Forensic Science: Fundamentals & Investigations, Chapter 6

29. Summary
Fingerprints have long been used for identification, and in the mid-1800s were recognized as unique to each person.
Three main groups include arches, whorls, and loops.
Basic analysis includes looking for cores, deltas, and making a ridge count.
Investigators search for patent, plastic, and latent prints.
Dusting with powders or using special chemicals can make latent fingerprints visible.
New developments may eliminate errors by analysts.
Forensic Science: Fundamentals & Investigations, Chapter 6