1. FORENSIC SCIENCE Fingerprints

2. History
3000 years ago: Chinese used fingerprints to sign legal documents
1880: Henry Faulds suggested that friction ridges be used to identify criminals. (Faulds actually wrote a letter to Charles Darwin regarding fingerprinting but Darwin thought that his cousin Galton would find it more interesting.)
Several years before Bertillon: William Hershel required natives of India to sign contracts with the imprint of their right hand. (There was a dispute between Faulds and Hershel over which of the two was the first to propose fingerprints as a method of identification.)

3. History cont. 1883 - Bertillon introduced anthropometrics
1891 – Dr. Juan Vucetich uses the work of Galton to refine a classification system (still used in Spanish speaking countries).
1892 – Galton describes loops, whorls, and arches
1897 – Sir Edward Henry develops the classification system that is used in the U.S.
1924 – FBI Identification Division Established

4. Automated Fingerprint Identification System
AFIS
Automated Fingerprint Identification System
AFIS is one of the three significant electronic databases for law enforcement purposes.
There are two types of files:
Knowns: Contains prints of known individuals
Forensic files: Consists of images from unsolved cases

5. Fundamental Principles of Fingerprints
A fingerprint is an individual characteristic.
A fingerprint will remain unchanged during an individual’s lifetime.
Fingerprints have general characteristic ridge patterns that permit them to be systematically classified (arch, loop or whorl).

6. Ridge Characteristics
Minutia--lines of the fingerprint
ridge ending
bifurcation
short ridge island
dot or fragment island
enclosure

7. MINUTIA
BIFURCATION
RIDGE ENDING

8. MINUTIA
DOT or FRAGMENT
SHORT RIDGE
ISLAND
ENCLOSURE

9. MINUTIA Exits: describes the direction of lines coming in or out
Deltas: triangle with ridges radiating outward in 3 directions.
How many exits and deltas are present?

10. Fingerprint Patterns
Arch
Loop
Whorl

11. Arch Least common pattern (5%)
An arch has 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.
Summary:
Exits: 2
Deltas: 0
Least common pattern (5%)

12. Arch
Summary:
Exits: 2
Deltas: 0

13. Loop
A loop must have one or more ridges entering and exiting from the same side it began. Loops must have one delta.
Summary:
Exits: 1
Deltas: 1
*Most common pattern (60%)*

14. Loop
Exits: 1
Deltas: 1
*Most common pattern (60%)*

15. Whorl Summary: Exits: 0 Deltas: 2
A whorl has at least one ridge that makes a complete circuit and two points of delta
Summary:
Exits: 0
Deltas: 2

16. Whorl
Summary:
Exits: 0
Deltas: 2

17. Fingers 2 8 1 2 16 8 4 1 16 4

18. Dactyloscopy
The practice of using fingerprints to identify someone.

19. Tracking Down Fingerprints
Patent Prints
Plastic Prints
Latent Prints

20. Patent Prints
Patent prints occur when a substance such as blood, ink, paint, dirt, or grease on the fingers of the perpetrator of a crime leaves behind a readily visible print.

21. Plastic Prints
Plastic prints have a three- dimensional quality and occur when the perpetrator impresses a print into a soft substance such as wax, putty, caulk, soap, cold butter or even dust.

22. Latent Prints
Latent fingerprints are those that are “hidden” and are not visible to the naked eye. These prints consist only of the natural secretions of human skin and require treatment to cause them to become visible.

23. 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)
Apocrine--secrete cytoplasm and nuclear materials
Sebaceous --secrete fatty or greasy substances.

24. Skin Layers

25. Lifting Latent Prints
Here’s where the chemistry comes in…
Developing a print requires chemicals 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.

26. Lifting Latent Prints (cont)
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.
Ninhydrin--reacts with amino acids to produce a purple reaction.
Silver nitrate--react with chlorides to form silver chloride, a material which turns gray when exposed to light.
Cyanoacrylate--”super glue” fumes react with water and other fingerprint constituents to form a hard, whitish deposit.

27. Lifting Latent Prints (cont)
In modern labs and criminal investigations, lasers and alternative light sources are used to view latent fingerprints. It was first used by the FBI in Since lasers can damage the retina of the eye, special precautions must be taken and a filter used.

28. Lights & Lasers

29. Iodine Fingerprint

30. Iodine Fingerprint

31. Ninhydrin Fingerprint

32. Ninhydrin Fingerprint

33. Cyanoacrylate Fingerprints

34. Cyanoacrylate Fingerprints

35. Will West & William West
May 1, 1903 – Will West went to Leavenworth Penitentiary in Kansas. The clerk thought that he looked familiar but Will denied ever being there. Coincidentally, there was another inmate named William West. They looked very much the same and had the same Bertillon anthropometric measurements but they denied ever knowing each other.

36. Will West & William West
Fingerprints helped authorities distinguish between the two Wills. So much for measuring the width of a person’s head. Leavenworth immediately dumped the Bertillon anthropometric system and switched to a fingerprint system.
P.S. This wasn’t just a bizarre coincidence. A report in the Journal of Police Science and Administration in revealed that they were indeed identical twins and each wrote letters to the same brother and five sisters and the same Uncle George.

37. Bertillon’s Embarrassing Moment
Bertillon reluctantly agreed to add fingerprints to his bertillonage profile. However, he added only those of the right hand.

38. This is where Mona Lisa comes in…
On August 21,1911, Leonardo da Vinci’s famous painting Mona Lisa was stolen from the Louvre Museum in Paris. The thief left a clear thumbprint on the glass that had protected the masterpiece. No system of classification had been devised yet so Bertillon and his assistants spent several months digging through his files. They found no match.

39. Mona Lisa cont.
Two years later police apprehended the thief, Vicenzo Perugia. His prints matched the ones found at the newest crime scene. It turns out that Perugia’s prints were among those in Bertillon’s possession the whole time. No match had turned up because the print found at the scene of Mona Lisa was from Peruglia’s left thumb and Bertillon’s files contained only that of Peruglia’s right thumb.

40. Homework Questions What is dactyloscopy?
List and describe (exits and deltas) of the 3 fingerprint patterns.
Draw the following minutia:
bifurcation
short ridge / island ridge
eye/island enclosure
Identify and describe the 3 kinds of fingerprints (not patterns).
List the different ways in which we can lift prints. What color do prints appear for each method?