Ever wondered what are fingerprints? In their basic form fingerprints provide our fingertips with enough traction to be able to grip and hold on to things with our fingers. However, fingerprints, or fingerprinting, have also been used for thousands of years as a marker for someone’s identity. Fingerprints were used in Ancient Babylonian times as a type of signature. To protect themselves against forgeries and cheaters, both parties would stamp their fingerprint on a clay tablet where the contract agreement was written. The Ancient Chinese would use fingerprints as a way to seal envelops, as well as sign contracts and authenticate loans. Fingerprints have also been discovered on ancient clay pottery artefacts from Minoan, Egyptian, Babylonian, Roman, Greek, and Chinese culture, where the potter had either used his fingerprints to add to the decoration, or had unintentionally left his mark while creating the pottery piece.
Nowadays, fingerprints had used as an effective evidence technique to catch criminal by matching their unique set of fingerprints to crime scenes. Because no two individual fingerprints are the same, the art of fingerprinting has revolutionised crime solving.
As already said, the use of fingerprinting as a form of identification has been around for thousands of years. However, a key breakthrough in fingerprinting was classifying fingerprints. It was Charles Darwin’s cousin, Sir Francis Galton, an English scientist who identified the basic pattern of fingerprints in 1892. At the turn of the century the head of the London Metropolitan Police, Sir Edward Henry, identified the four different types of fingerprints: arches, whorls, loops and composites, which are a combination of the other three. Due to this type of identification and classification, searching for matches among fingerprints instantly became easier, and began to revolutionise crime solving techniques.
Fingerprinting has revolutionised the way that crimes are being solved and criminals are being caught. Like DNA, fingerprints are completely unique, with no two fingerprints the same, making it a perfect way to successfully identify suspects and tie them to the scene of the crime.
In 1955, police conducted fingerprinting of almost 9000 men near London in an attempt to find the murderer of a woman who had been killed on a golf course. The murder weapon was a long metal pole that had been used to mark the 17th tee. On the pole police discovered a palm print. After the mass fingerprinting, police caught Michael Queripel, who was convicted of the woman’s murder.
In Australia in 1935, a shark was on display at the Coogee Aquarium in Sydney. As it was swimming around, it threw up a human arm that had a tattoo on it depicting two boxers. In a police investigation, they managed to take fingerprints from the well-preserved arm and identified it as belonging to a local boxer and criminal Jim Smith. The mystery was further deepened when investigators discovered that the arm had not been chewed off by the shark, but rather it had been cut clean off Smith’s body. Police were investigating two suspects, but one of them died and the case against the other one collapse. It is believed that Jim Smith was murdered, but no one knows who killed him, and the rest of his body was never recovered. The case famously became known as The Shark Arm Mystery.
In the US in the summer of 1984, there were 12 violent deaths of men and women, all murdered by a man nicknamed ‘Nightstalker’. Survivors of the attacks described him as tall, Hispanic and had bad teeth. One survivor managed to remember the car’s license plate number as the attacker drove away, and police tracked down the car, which turned out to be stolen. Inside the car they discovered a fingerprint.
At the time, the Los Angeles police department were in the process of computerising its fingerprint database - scanning all their recorded fingerprints into the computer so they could be quickly searched and cross-referenced to find a match. After a computer search, the fingerprint was matched to a man who had previously been arrested for a traffic infringement. His name was Richard Ramirez. He denied all knowledge of the murders even after police discovered his firearm and some of the jewellery he had stolen in his friends’ and relatives’ homes. In November 1989, Ramirez was sentenced to death.
How do You Find Fingerprints?
The Different Types of Fingerprints
At crime scenes, forensic investigators look for three types of fingerprints - visible, plastic or latent prints.
Visible prints are exactly what they sound like; clear prints that can be seen with the naked eye. The prints can be easily seen on glass or windowpane without the need for special powders for them to be revealed. The fingerprint is left by a combination of bodily fluids, such as sweat, or dirt , or some other material that is on the skin that created a visible smudge or mark.
Plastic prints are also easy for investigators. These prints are made from impressions that are left in soft substances, such as soap, putty, paint or wax.
Latex prints are a challenge for investigators to find. These types of prints are produced by natural oils and sweat, therefore making them hard to see on surfaces.
To find latent prints at a crime scene, investigators dust the surfaces of objects or places that a criminal might have touched. The dust sticks to the print’s oily residue and investigators use a special tape to peel off an impression that can then be photographed. This dusting requires different coloured powders. Black carbon powder is dusted on light surfaces. White aluminium powder is used on dark surfaces. Fluorescent powders are used on highly coloured or decorative surfaces to show up under ultraviolet light.
For latent prints on paper or cloth, a dye is used. Investigators will then take sample prints from alleged suspects using an ink pad, and stamping their prints on to a police record sheet. An alternative is to that is to use a laser scanner to record fingerprints. This provides a quicker means of cross-referencing prints with a growing computer database of information.
Fingerprints have been used for thousands of year as a form of identification. By understanding what fingerprints are, and identifying that there are no two fingerprints made the same, they have revolutionised the way suspects and criminals can be tied to a crime scene.