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Forensic Science Fingerprinting - D. Scott

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Daron Scott

on 22 September 2016

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Transcript of Forensic Science Fingerprinting - D. Scott

Fingerprints and Fingerprinting
Will West
William West
The History of Fingerprinting
1882 - Alphonse Bertillon was a policeman and created a way to identify criminals. The first method used to classify repeat offenders was called Bertillonage. Using this method, people were measured in arm length, head size, wingspan, etc.
The earliest use of fingerprinting was used to
authenticate official documents. The oldest known
document dates from the third century B.C.
1684 - Dr. Nehemiah Grew first wrote a paper describing patterns (fingerprint ridges) that he saw on human hands and feet.
1788 - Johann Mayer followed up on his work and
described the ridges on the hand as follows. "the
arrangement of skin ridges is never duplicated in
two persons."
First scientist to recognize this fact.
1823 - Jan Evangelist Purkyn described nine distinct
fingerprint patterns, including loops, spirals, circles,
and double whorls.
1858 - Sir William Herschel was the first to understand the value of collecting fingerprints and using them as identification on contracts. When working in India he would have locals use their whole hand print as a way of "signing" the contract.
In 1903, a case at Leavenworth prison might have forever changed how people are identified. Two men, Will and William West, were imprisoned at the same time. Upon arriving at the prison the clerk told Will West that he had been there before and insisted that he had already had his picture taken. When the clerk went to the files, the picture on the right is the one he retrieved.
1900 - Sir Francis Galton and Sir E.R. Henry published a book on the classification system for fingerprinting which Scotland Yard implemented in 1901. This method is still in use today.
The study or science of fingerprinting
is called Dactyloscopy. So, fingerprints
are also referred to as dactylograms.
There are three distinct ridge patterns.
The loop (65%), whorl (30%), and arch(5%).
Loops
There are two basic types of loops called an ulnar or radial loop. Loops which flow in the direction of the ulna bone (toward the little finger) are called ulnar loops and those which flow in the direction of the radius bone are called radial loops. If the ridges flow in from the little finger side this would be an 'ulnar' loop.
Loops and Whorls usually have two very distinct features.
The core is the center of the loop or whorl and a delta is
a triangular shaped region near the core.
A ridge count is drawing a line from the core
to the delta and counting all fingerprint ridges in between.
What kind of loop is this if it on your right thumb?
Whorls will have at least one ridge that completes
a circle or circuit. They will have at least two deltas.
If there are more than two deltas then the whorl is
probably an accidental whorl.
4 Main Types of Whorls
Arches are the simplest type of fingerprints that are formed by ridges that enter on one side of the print and exit on the other. No deltas are present.
3 Types of fingerprints found by investigators

Patent Fingerprints - are visible prints left on a
smooth surface when blood, ink, or some other
liquid comes in contact with the hands and transferred to the surface.
Plastic Fingerprints - actual indentations left in some
soft material such as clay, putty, or wax.
Latent Fingerprints - sometimes called hidden prints are
caused by the transfer of oils and other body secretions onto
a surface. They are made visible by dusting with powders.
In 1987, the FBI had 23 million fingerprint
cards on file. This required manual searching
to find a match.
In 1999, the FBI developed the Integrated
Automatic Fingerprint Identification System.
Also known as IAFIS or AFIS. It currently has over 70 million prints on file and 73,000 terrorists. The response time for this system is about 27 minutes.
Central Pocket Whorl
Minutiae Points - small detailed features of a fingerprint that make it distinct. It is typical to require about 10-12 identical points to make the fingerprint a match.
June 1892, In Argentina a young male and female are found murdered. Six-year-old Ponciano Rojas and his four-year-old sister Teresa Rojas. Their mother, Francesca Rojas, claimed that their neighbor, a man named Pedro Ramón Velásquez had committed the crime, as she rejected his sexual advance earlier in the day and then later saw him running out of the door of the house right before she “discovered” the bodies. When investigator Juan Vucetich (Voo-ce-tich) arrived, he noticed a bloody thumbprint on the door of the house. He then printed the mom, Francesca, and her print was a match. She would later confess to murdering her two kids in order to marry her boyfriend who disliked children. She was sentenced to life in prison.
Loops
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