1. Target 2-3 Tuesday, October 24, 2017
Fingerprints
Target 2-3
Tuesday, October 24, 2017

2. Target 2-3
I can match fingerprints by developing, classifying, and analyzing fingerprint evidence.

3. Fingerprints are…
Impressions left behind when friction ridges of human skin come in contact with smooth surfaces

4. Principles of Fingerprints
A fingerprint is unique to an individual. Identical fingerprints have never been found.

5. Principles of Fingerprints
A fingerprint will remain unchanged throughout the life of the individual, even as skin grows, is damaged, and heals.

6. Principles of Fingerprints
Fingerprints have general ridge patterns that allow them to be systematically classified.

7. Classifying Fingerprints
Look for deltas and cores
Delta = small triangle in the print, formed where ridges split apart
Core = small circle in the print, formed where ridges close in on themselves

8. Classes of Fingerprints
Arches
Plain Arch
Tented Arch
Loops
Ulnar/Radial Loops
Whorls
Plain Whorl
Central Pocket Loop
Double Loop

9. Arches
An arch is formed by ridges entering from one side of the print and exiting on the opposite side.
Zero deltas
Zero cores
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10. Plain Arch Zero cores Zero deltas
Ridges enter on one side, rise just a bit, and exit on the other side
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12. Tented Arch Zero cores Zero deltas
A tented arch rises sharply upward causing the center of the print to look like a tent.
Ridges bend at less than 90 degrees
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15. Loops
A loop must have one or more ridges that enter from one side of the print, curve around, and exit the same side
One delta
Zero cores
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16. Ulnar Loops An ulnar loop opens toward the little finger
Print from the right hand
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18. Radial Loops A radial loop opens toward the thumb
Print from the right hand
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20. Whorls
One or more cores
Two deltas
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21. Plain Whorl Two deltas One core
At least one ridge that makes a complete circuit
Looks symmetrical – deltas are evenly spaced on each side of the core
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22. Plain Whorl Two Deltas One Core Displays a degree of symmetry
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24. Central Pocket Loop Two deltas One core
At least one ridge makes a complete circuit
At least one ridge enters and exits the print from the same side
Not symmetrical
One delta off to the side
One delta near the core
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25. Central Pocket Loop Two Deltas One Core Lacks Symmetry
A delta is observed near the core
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27. Double Loop Two deltas Two cores
A double loop is made up of two loops combined into one fingerprint.
Looks like an “S”
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28. Double Loop Two Deltas Two Cores Appears to have an “S” in the print
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30. Accidental All other prints Can have any number of cores and deltas
Cannot be classified as anything else
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