1. Fingerprints
Forensic Science
Al Capone’s Fingerprints

2. History of Fingerprints
1000 BC – Chinese sign legal documents with fingerprints.
Not sure if they knew the significance
1685 – Marcello Malpighi at the University of Bologna recognizes fingerprint patterns
loops, whorls, and arches
1823 – Purkjne identifies 9 basic fingerprint patterns, forming the basis of today’s classification.
1858 – Herschel makes natives in Bengal, India sign documents with a hand imprint.
He notices that prints do NOT change over time.
1883 – Bertillon System is developed

3. Bertillon System First systematic attempt at personal identification
Consisted of:
precise measurements of body parts (anthropometry)
Detailed description of the subject
Full length photograph
System was Flawed…

4. Case Study of Bertillon System
Will West Case: 1903
Will West went to Leavenworth Penitentiary in Kansas.
The records clerk thought he looked familiar, but he denied every being incarcerated.
Prison officials investigated and found another William West at Leavenworth with the exact same Bertillon measurements as Will West.
The two Wests denied being brothers or having any knowledge of each other.
Fingerprints helped distinguish between the two Wests.
The Bertillon System was immediately dumped

5. History of Fingerprints Cont…
1880 – Faulds (a surgeon) writes that fingerprints can be used for personal ID.
1892 – Galton published the first text book on fingerprints (“Finger Prints”)
Described patterns, established that no two prints were identical, and prints remained unchanged throughout life.
1899 – Sir Edward Henry devises a classification on 5 types of prints
A modified system of the Henry classification system is used by the FBI today in the US.
1910 – Thomas Jennings was the first person convicted for murder in Chicago on fingerprint evidence – LANDMARK CASE.

6. Bertillon’s 2nd Big Mistake !
1910 – Bertillon adds fingerprints to his Bertillonage profile but only includes the right hand…. BIG MISTAKE!
Case Study: 1911
Da Vinci’s Mona Lisa was stolen.
Left at the crime scene was a thumbprint of the left hand of the criminal.
Bertillon did not have data for the left hand and the perpetrator was not found for another two years.

7. Fundamental Principles of FP
A Fingerprint is individual and NOT shared by two people – even twins
A Fingerprint will remain unchanged during an individual’s lifetime.
John Dillinger Case Study
3. The individuality of fingerprints is NOT determined by its general shape or pattern but by careful study of the ridge characteristics. (Minutiae)

8. John Dillinger Case Study
In an effort to avoid police, underwent facial plastic surgery and tried to remove his fingerprints by burning them off with acid.
Despite his efforts… prints taken at the morgue still matched the ones on file.

9. Composition of Skin Skin is composed of layers of cells
Epidermis – closest to the surface
Dermis – inner skin
Dermal Papillae – area in between the Epidermis and Dermis.
Determines the ridge pattern
Develops in the human fetus
In order to change the pattern, damage would have to penetrate to 2mm beneath the skin’s surface (OUCH) and then the scars would become a pattern – efforts to change are futile!

10. Minutiae
There are as many as 150 ridge characteristics on an average print
Most of the time only partial prints are recovered at a crime scene
There is no set criteria number of characteristics that must match to consider prints the same.
Generally 8-16 matches found by an expert are considered a good match.

11. Three Classes of Prints
Loops
65% of the population
One or more ridges that enter from one side and curve and exit from the same side.
Ulnar loop – opens toward the little finger
Radial loop – opens toward the thumb
Must have at least one delta (point of divergence.)
Delta

12. Three Classes Cont… 2. Whorls 3. Arches
30-35% of the population
4 types: Plain, central pocket, double loop and accidental
Minimum of 2 Deltas
3. Arches
5% of population (very rare)
2 types: plain and tented
Since the 1970’s technological advances have made possible the classification and retrieval of fingerprints by computers.
Use AFIS – Automated Fingerprint identification systems

13. Methods of Detecting Prints
Visible Prints – contact with colored material such as paint, blood, grease, or ink leaves a noticeable print.
Plastic Print – impression left on a soft material such as putty, wax, soap, or dust
Latent Prints – caused by the transfer of body perspiration or oils on fingers to an object (Invisible to the eye)
Need a developer to aid in discovery

14. Developers for Nonporous/Nonabsorbent Surfaces
Super Glue – cyanoacrylate reacts with sodium hydroxide releasing a vapor that binds with the amino acids forming a white latent print.
Powder – adheres to oils and moisture in the prints making it visible. (The color of powder used, depends on the material where the print was left.)
RUVIS – Reflected Ultraviolet Imaging System, detects print in its natural state by aiming UV light at the prints.

15. Developers for Porous/Absorbent Surfaces
Iodine Fuming – iodine vapors combine with oils to visualize prints. (Must be photographed immediately…will disappear over time.)
Ninhydrin – forms purple-blue color with amino acids present in perspiration. (Most popular method.)
Physical Developer – silver nitrate-based chemical mixture used to visualize prints. Shown to be effective at visualizing prints that are undetected by other methods.

16. Fingerprint Processing
Should not be preformed at the crime scene.
Items should be submitted to the lab
Once latent prints are visualized they must be permanently preserved for future comparison and possible use in court as evidence. (Usually photographed)
Fingerprints can now be enhanced for the most accurate and comprehensive analysis using digital imaging.