Fingerprints

History of Fingerprints Fingerprints pressed into clay tablet contracts have been found that date back to 1792-1750 BC in Babylon In ancient China, fingerprints were inked onto all official documents like contacts and loans The oldest known fingerprinted document is from third century BC China The oldest known study of fingerprints in Western culture is from 1684

In 1788, Johann Christoph Andreas Mayer discovered that no two people have the same fingerprints Fingerprints were first gathered from criminals in Paris in 1879 by Alphonse Bertillion Bertillion's system identified a repeat offender in 1883, and was used to solve a murder in 1902 In 1896, Sir Edmund Richard Henry invented the ten card, which is still in use today The ten card has a place for all ten fingerprints, plus places for all five prints on each hand taken at once

Formation of Fingerprints Fingerprints are a result of the raised ridges on the tips of the fingers The print that is left behind is made of natural secretions from the sweat glands Combination of water, oils, salts, and dirt Fingerprints form in the womb, usually at the beginning of the 10th week of pregnancy Prints on the palms, soles, and lips also form at this time

The fingerprints are made in the basal layer, a special layer in the epidermis where new skin cells are made In a fetus, the basal layer grows faster than the epidermis on the outside and the dermis on the inside Because of its fast growth, the basal layer collapses and folds in different directions The pattern cannot be changed by skin injuries because the epidermis protects it

Characteristics of Fingerprints Fingerprints can be loops, whorls, and arches 65% of the population have loops 30% of the population have whorls 5% of the population have arches

Loop Whorl Arch

The ridges on loops enter the center of the finger from the left or the right side and exit from the same side they enter

Whorls look like a bullseye

Arches have ridges that enter from one side and exit from the other

The core is the center of a loop or a whorl A triangular region located near a loop is called a delta Some of the ridge patterns near the delta will rise above the triangular regions, and others will fall below

A ridge count can be used in identification as well In order to take a ridge count, you draw a line from the center of the core to the edge of the delta and count all the ridges that are crossed

Types of Whorls Whorls can be plain (24%), central pocket loop (2%), double loop (4%), or accidental (0.01%) The plain whorl has one or more ridges that make a complete spiral It has two deltas A line between these two deltas will cross at least one of the center ridge lines

The central pocket loop whorl has one or more ridges that make a complete circle It has two deltas as well, but a line drawn between them will not cross any of the center ridge lines

The double loop whorl has two separate loop formations and two deltas

The accidental whorl has two deltas, and its ridge lines are a combination of two other whorl patterns

Types of Arches Arches can be plain (4%) or tented (1%) In the plain arch, ridges enter from one side, rise in the center, and exit from the other side There are no angles and no loops

The tented arch has all the characteristics of the plain arch, but it does make an angle in the center A delta may be present towards the center

Minutiae Every individual, including identical twins, has their own unique ridge pattern due to minutiae Minutiae are very small details in the ridge patterns of fingerprints Minutiae, along with ridge counts, the differences between ridges, and their locations make up fingerprint identification There are about 150 individual ridge characteristics on one fingerprint

When forensic investigators examine a fingerprint, they are identifying the unique signature of a person In order to match fingerprints, a minimum number of comparison points are needed

Types of Fingerprints Patent fingerprints are visible prints that are left on a smooth surface Blood, ink, or some other liquid comes in contact with the hands, and the hands transfer that liquid to the surface Plastic fingerprints are indentations left in soft materials like clay, putty, or wax Latent fingerprints are caused by the transfer of oils and other body secretions onto a surface Latent prints are invisible until they are dusted with powder

Can Fingerprints Be Altered or Disguised? For the most part, no Fingerprints may be altered, but only by long- term contact with very rough surfaces John Dillinger tried to alter his fingerprints using acid Acid does burn off fingerprints, but they always grow back

How Reliable Is Fingerprinting as a Means of Identification? Due to human error and judgment, fingerprint identification is not 100% In a recent test of fingerprint analysts, it was found that one in five analysts made one false- positive identification For this reason, results are often checked and double-checked

How Are Fingerprints Analyzed? Before 1999, all fingerprint analysis was done manually The FBI has developed the Integrated Automated Fingerprint Identification System (IAFIS or AFIS) IAFIS provides digital, automated fingerprint searches, electronic storage of fingerprint photographs, and electronic exchange of results and files IAFIS runs 24 hours a day, 365 days a year

Law enforcement agencies can now get fingerprint results through IAFIS within 2 hours Within IAFIS, there is the Criminal Master File, which contains the fingerprints and criminal histories of 47 million people This is the largest database of its kind in the world Local and federal law enforcement agencies voluntarily submit information to the Criminal Master File Local and federal agencies do not, however, pool their data

How Are Latent Fingerprints Collected? Dusting a surface with special powder makes the prints visible Tape is then used to lift and preserve the fingerprint The tape is placed on an evidence card that contains the date, time, location, and collector's name Fingerprints are always photographed before they are lifted

Getting a latent print off a surface that is not smooth requires chemicals When the fingerprint residue combines with these chemicals, the print becomes visible

The Future of Fingerprinting New digital scanning technology is allowing fingerprints to be scanned at the rate of 500- 1000 dpi. This high resolution allows us to see the pore patterns on the ridges. This leads to better fingerprint matching. We are also investigating better methods of identifying substances that are transferred to our fingerprints when we touch things. Ex: gunpowder residue