1. CSI:Ibstock
Lesson 2

2. Fingerprint analysis “Fingerprints can not lie,
but liars can make fingerprints.”
—Unknown

3. A murder attempt has taken place, no-one was harmed but a pistol was left at the scene. The pistol grip is dusted down and fingerprints are taken back to the lab. The results are put into the database and after 30 seconds of pained whining from the computer a perfect match comes up. 99.8% match, there is no doubt. The Inspector looks at who matches the prints and raise an eyebrow. ‘Odd’ they say, then they pick up the phone. A squad is sent to their attackers place of work, the zoo. After 15 minutes the officers return with the attacker in handcuffs.

4. Fingerprints Forensic science students will learn:
Why fingerprints are classed as individual evidence.
How to detect fingerprints
How computers have made personal identification easier.

5. Students will be able to:
Fingerprints
Students will be able to:
Define the three basic properties that allow individual identification by fingerprints.
Obtain an inked or graphite resolved, 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.

6. Fingerprints overview
Recording Prints
rolling inked prints or graphite resolved
primary identification number
Lifting Prints
Black and white powder
Chemicals—ninhydrin, iodine and cyanoacrylate
Other Types of Prints
Palm, lip, teeth, eye, ear, voice, shoe and footprints
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7. Dactyloscopy The study of fingerprints
Historically
Chinese, Egyptians and Greeks – signed documents
William Herschel—required Indians to put their fingerprints on contracts, and also as a means of identifying prisoners
Henry Faulds—claimed that fingerprints did not change over time and that they could be classified for identification
Alphonse Bertillon—proposed body measurements as a means of identification; termed anthropometry
Francis Galton—developed a primary classification scheme based on loops, arches and whorls.
Edward Richard Henry—in collaboration with Galton instituted a numerical classification system
Juan Vucetich—developed a fingerprint classification based on Galton’s that is used in Spanish-speaking countries

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Why do we have fingerprints?
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9. Fundamental Principles of friction ridges (fingerprint)
A fingerprint is unique to an individual as a characteristic (even identical twins have different prints)
A fingerprint will remain unchanged during an individual’s lifetime.
Fingerprints have general characteristic ridge patterns that allow them to be systematically classified.

10. Ridge Characteristics
Minutiae—characteristics of ridge patterns
Ridge ending
Short ridge
Dot or fragment
Bifurcation
Double bifurcation
Trifurcation
Bridge
Island
Enclosure
Spur 9

11. Fingerprint minutiae 10

12. 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 11 11

13. 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?
Radius
Ulna
Left Hand 12 12

14. 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
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15. Fingerprint Facts: 60% of people have loops 35% have whorls
5% have arches
Brothers Alfred and Albert Stratton were the first people to be convicted of murder using fingerprinting evidence in (1905) 14 14

16. ? A B
Right Hand
Left Hand C
Right Hand D E
Right Hand
Left Hand

17. Taking prints 16 16

18. 17 17

19. Primary Classification
The Henry—FBI Classification
Each finger is given a point value
left
right 18 18 18

20. Primary Classification
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 =
right right right left left
thumb middle little index ring
That number is your primary classification number 19 19 19

21. Comparison
There are no legal requirements in the United Kingdom on the number of points. Generally, criminal courts will accept 8 to 12 points of similarity. 20 20 20

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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.
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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Types of print:
Visible (patent) – left by dirt, grease, blood, etc. Does not need processing
Impression (plastic) – indentation in soft material (butter, wax, putty, tar, etc.)
Latent – requires processing to make visible and suitable for analysis
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24. Developing Latent Prints
Developing a print requires substances that react 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.
Powders—adhere to both water and fatty deposits. Choose a color to contrast the background.
Iodine—fumes react with oils and fats to produce a temporary yellow brown reaction. Starch can be used to stain the iodine fingerprint.
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25. How to use a powder (white or black) to resolve and lift a print
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27. Iodine Fingerprint Kendall/Hunt Publishing Company26 26 26 26 26

28. Developing Latent Prints
Ninhydrin—reacts with amino acids to produce a purple color. You need
Cyanoacrylate—“super glue” fumes react with water and other fingerprint constituents to form a hard, whitish deposit.
In modern labs and criminal investigations, lasers and alternative light sources (UV) 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 (wearing goggles)
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29. Ninhydrin fingerprint
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30. Cyanoacrylate Fingerprints
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Other prints
What other types of print could you get from a crime scene?
Ears—shape, length and width
Lips – shape, surface structure, length, width
Teeth – bite marks
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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IDENT1 and AFIS
IDENT1 (UK) and AFIS (Automated Fingerprint Identification System) is a computer database that stores and searches for fingerprints (latent and developed)
These systems are quicker than the old system of manual examination.
There is not one complete system across the world.
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33. Biometrics – the future
Use of some type of body metrics for the purpose of identification. Used in biometric passports and at airports.
Used to stop identity theft
iPhone has biometric home key and new computers have biometrics
Used today in conjunction with IDENT1 (UK) and AFIS (USA)
Examples include retinal or iris patterns, voice recognition, handwriting
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