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Wednesday, June 19, 2013

A little about Fingerprint

The fingerprints of any human are very typical because for all human have different fingerprints. If the human's physical changes occured,  it did not alter their fingerprints. The fingerprints are considered the most accurate tool for identifying criminals. Fingerprints have been known since prehistoric times. There are so many prehistoric relics that show the use of fingerprints as a sign of a person.

However, only in the early 20th century, modern fingerprint used to identify victims and perpetrators of crime. Forensic investigation using fingerprints came into use in 1915, along with the establishment of the International Association for Identification (IAI). Then in 1977 the IAI began to impose certification standards for fingerprint examiners.
In ancient China, thumb prints were found on clay seals. (Picture from: http://www.inspirationline.com/)
Before the 1800s, law enforcement agencies use visual display memory to identify the perpetrator of the crime. However, this method was not effective, because the visual appearance of a person can be easily modified.

The Bertillon System, using 
measurements of parts of the body.  
(Picture from: http://www.inspirationline.com/)
Around 1870, the French anthropologist, Alphonse Bertillon encourage the use of identification based on characteristic of specific bone organs. This system makes more sense because the bones of a person is also not easy to change. The Bertillon's system included measurements such as head length, head width, length of the middle finger, length of the left foot; and length of the forearm from the elbow to the tip of the middle finger.

In the first 30 years after its discovery, the system is received in the process of identifying criminals. Now the criminals identification that using methods typical bone shape is no longer used. As reported by the onin.com, that in 1903 a case of a man named Will West in Leavenworth, charged with having a form similar to a typical bone alleged offender named William West. It turns out Will and William West was a twin. When the court examined their fingerprints, the results was Will West and William West are two different people even though they were born twins.

Since that's the method to identify victims and perpetrators of crime using fingerprints. In July 1892, Police Inspector Alvarez of the La Plata Central Police, Argentina difficulty unravels the mystery deaths of two children in their slum, Francisca Rojas the mother was being accused, but she did not want to confess. Thanks to his thoroughness, Alvarez found a bloody thumb print on the door. When matched, the prints fit with Francisca's right thumbprint. Then this sadistic mother defenses collapsed and confessed. The Rojas case is the first criminal case is solved by fingerprints finding at the crime scene. No wonder when Argentina became the first country in the world that uses fingerprints as a single method of identifying criminals.

More than 30 years before William Herschel, British civil servants in India, around 1858 it was noticed that the surface of the hand-striped, and that each person's fingerprints distinctive and unchanging.

When he returned to London in 1880, Herschel reading Dr. Henry Faulds's paper in the Nature journal about fingerprints. According to Faulds who has long worked in Japan, it has been for centuries the local community using fingerprints. In fact, from the sweat pores in the fingertips leave prints as accurately as blood or ink blots.

Then Faulds advise the police to find fingerprints on every scene of the crime. Unfortunately, just like Faulds, Herschel posts in Nature are not considered people. Until in 1888, when a famous British scientist, Sir Francis Galton was looking for a method to identify the perpetrators thought of the work of Faulds and Herschel. Galton who later became a fanatical supporter of fingerprints. He argues, that need a simple classification system when bifurcations will be used in everyday practice police service.

Edward Henry in 1869, when he became inspector general of Bengal, India, managed to find a fingerprint classification system called the Galton-Henry classification system. Five years later the classification method used by Scotland Yard.

Subsequently became known the dactyloscopy term, which is a branch of science that specifically study the fingerprints use as a means of identification which is indispensable in modern law enforcement. Included are the finger cleaning with gasoline, dry it, and then rolled into the glass surface that has been coated printing inks. Furthermore the fingers carefully on the card to attach to the mold produces a light gray with clearly legible distance between strokes so it can be calculated and tracked.

To search for hidden fingerprints left by criminals, known as latent fingerprints, fingerprint experts should find the location fingerprints, preserve, and identify the bifurcations. In latent fingerprints, scratches that are not reproduced in ink, but other substances such as perspiration, dirt grease, or other natural materials that exist on finger the villain. Most latent fingerprints colorless therefore need to be made "invisible" by applying a powder gray or black that contains content of chalk or soot is mixed with other substances. Furthermore latent fingerprints were photographed or lifted with tape to be kept as evidence.

While the Galton-Henry fingerprint patterns divide into 5 basic types, the FBI, grouped it into 8 patterns:
  1. Radial loop - this is a concentric pattern. The pattern is slanted towards the radial bone, the thick bone on the thumb side of the hand.
  2. Ulnar loop - this the most common pattern and is made up of ridges that resemble hairpins or staples. It sometimes resembles the radial loop but slants towards the small bone of the arm, the ulna, on the same side as the little finger.
  3. Plain arch - this is a mound like pattern.
  4. Tented arch - this patter resembles a church steeple.
  5. Plain whorl - this is a circular spiral pattern.
  6. Accidental - this is another, irregular circular pattern.
  7. Double loop - this is, as the name describes, two looped patterns.
  8. Central pocket - this is chracterized by a tight cicular pattern in the center of the print.
Fingerprints loop group dominates approximately 65% ​​of all fingerprint patterns, in one after another whorl approximately 35%, then the combined group and tented arch is only 5%. Since the 1920s, the FBI officially use the system. Results to date are FBI neatly storing more than 140 million sets of fingerprints in a computer, so the task to compare and identify it can be done quickly.
The FBI's fingerprint patterns. (Picture from: http://www.viewzone.com/)
Although Galton-Henry classification system most widely used police services around the world, this time also developed other techniques, such as the sound spectrograph that can mold the sound graph various variables such as frequency, intensity, and length of the sound. While DNA tests can also be used to identify a person through various types of physical elements are found, such as splashes of blood, semen, or a strand of hair. DNA testing was widely used in the proof of one's kinship, as in forensics. *** [EKA | FROM VARIOUS SOURCES | VIEWZONE | NET | GI | PIKIRAN RAKYAT 25042013]
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