Tattoo identification (Forensic Science)
Tattooing is a process in which ink or a substance containing dye is introduced into the dermis, a deep layer of the skin that does not regularly renew itself in the way the outer layer of skin, the epidermis, does. The ink or dye is usually deposited in the dermis through the use of an electric machine that produces very rapid movement of a needle (up to three thousand times per minute), although tattooing can also be accomplished by an individual using less professional methods. The dye is not soluble, and as the epidermis is shed, the tattoo remains visible. Tattoos do, however, often fade perceptibly over time.
Human beings have used tattoos for thousands of years for a variety of religious, cultural, and individual reasons. Governments have also used tattoos at various times throughout history to identify convicts, prisoners of war, and other groups, such as Nazi Germany’s tattooing of prisoner numbers on those held in concentration camps during World War II. In the United States, the numbers of persons getting tattoos to make personal statements of identity or group membership are believed to be on the increase. As of 2003, 16 percent of American adults reported having one or more tattoos, with women and men about equally likely to be tattooed. In general, personal tattoos in the United States are becoming larger and more prominently displayed, with increasing use of vibrant colors.
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Identification of Suspects (Forensic Science)
The knowledge that a criminal suspect has a tattoo may be extremely valuable to an investigator in identifying that individual. Many tattoos are placed on areas of the body that are easily visible to others, such as the arms, hands, face, throat, or neck. Additionally, tattoos are often brightly colored, and many feature easily recognizable and memorable items, objects, or words.
After a crime has been committed, it can often be difficult for witnesses to provide investigators with a clear description of the perpetrator, given that people who commit crimes often attempt to disguise some or all of their features, using gloves, hats, masks, and other devices. A tattoo that is not completely covered, or is momentarily exposed, can provide an important clue to a criminal perpetrator’s identity. Witnesses often have blurry or differing memories of events, but they may be able to recall seeing a tattoo of an easily recognizable object, such as a well-known cartoon character, even when they cannot provide police with information on the perpetrator’s eye color, height, or distinguishing facial features.
In addition to being useful for positive identification if a suspect is found, tattoos can give investigators possible leads. Many groups—such as street gangs, biker groups, and military divisions—have their own individualized tattoos that members get to identify themselves as part of their groups. If the...
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Identification of Human Remains (Forensic Science)
Tattoos are often extremely valuable evidence in the identification of human remains. When an individual is reported missing, any information about tattoos or other body modifications (such as piercings) that person has can be useful in helping investigators determine the identity of any human remains that are discovered. Even when a specific identification of unknown remains is not possible, tattoos on the body can help by providing starting points for investigation. For example, tattoos may indicate group membership or may indicate that the deceased was a regular customer at a local tattoo shop. Tattoos are usually visible until the body is significantly decomposed.
During investigations of major catastrophes involving large numbers of victims, such as the tsunami that hit Thailand in 2004 or the terrorist attacks on the World Trade Center in 2001, identification of victims is often strongly aided by the examination of tattoos. Also, forensic anthropologists often find tattoos helpful in the identification of bodies recovered from mass graves. When the mass graves are of recent origin, examination of tattoos may enable the identification of individual victims. When the mass graves are ancient, examination of tattooing may help to identify the groups or tribes to which the individuals in the graves belonged.
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Further Reading (Forensic Science)
Cox, Margaret, et al. The Scientific Investigation of Mass Graves. New York: Cambridge University Press, 2008. Presents a penetrating discussion of the techniques of identifying remains recovered from mass graves and also addresses the ethical issues involved.
Fenske, Mindy. Tattoos in American Visual Culture. New York: Palgrave Macmillan, 2007. Provides a history of tattooing in the United States, with a special focus on the cultural aspects of the tattoo through history.
McCartney, Carole. Forensic Identification and Criminal Justice: Forensic Science, Justice, and Risk. Portland, Oreg.: Willan, 2006. Discusses the forensic and legal issues involved in identification.
Rush, John A. Spiritual Tattoo: A Cultural History of Tattooing, Piercing, Scarification, Branding, and Implants. Berkeley, Calif.: Frog, 2005. Presents the history of tattooing and other body modifications, along with discussion of the functions tattooing has fulfilled in ancient and modern societies.
Thompson, Tim, and Sue Black, eds. Forensic Human Identification: An Introduction. Boca Raton, Fla.: CRC Press, 2007. Provides information about various techniques used by forensic experts to identify individuals both alive and deceased. Includes a section on identification using tattoos and other body modifications.
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Tattoo Identification (World of Forensic Science)
A tattoo is a design imprinted onto the skin that can sometimes be a useful mark of identification of a non-skeletalized body or a suspect using a false identity. It is believed that tattooing was first practiced in Egypt around 2000 B.C., and its use has spread around the world. Today a wide cross section of the population bears tattoos, from fashion models to known criminals and gang members. The designs are as varied as the people who wear them; names of loved ones are popular, as are symbols denoting membership of a group. Tattoos may be done just for fun, or they may have a more sinister connotation; for instance, prisoners have sometimes been tattooed with numbers, especially in concentration camps. Some elderly people may bear tattoos relating to experience in the Holocaust.
When a pathologist carries out an autopsy, he or she will look for and record tattoos in the same way as for any other body marks that could be identifying, like scars or birthmarks. The location and nature of the tattoo are the identifying features. A tattoo is made by inserting dyes or inks into piercings created by a needle. One approach to identifying the body is to extract a tiny amount of the dye and subject it to laboratory analysis. The pigments can be identified by techniques such as atomic absorption spectroscopy or thin layer chromatography and may be traceable back to a specific tattoo artist. Black pigments may contain carbon, reds mercuric chloride, and greens potassium dichromate.
Tattoos are valuable identification marks because they tend to be permanent. They can be removed, but they do not fade, and they persist even if the outer layer of skin has perished. The color may, however, change with exposure to the sun. Typically, blue pigment may turn black or purple.
When it comes to identifying a corpse, family members may be aware of the existence of a tattoo and this can be used as a distinguishing mark even if the body itself has been dismembered or otherwise mutilated. In one famous case, dating back from 1935, two fishermen caught a shark off the coast of Sydney, Australia, and took it to a local aquarium where the animal proceeded to disgorge a human arm. The limb appeared to have been severed by a knife, seeming to rule out a shark attack as the cause of death. It looked, rather, as if the corpse had been dismembered and disposed of at sea. The arm also bore a distinctive tattoo of two boxers squaring up for a fight. This led to the identification of the victim as James Smith, an ex-boxer with a criminal past. His wife recognized the tattoo, and fingerprint evidence confirmed the identity. Suspects were arrested, but the defense argued that an arm alone was insufficient evidence to convict, even if it did carry a tattoo and fingerprints. The case became known as the Shark Arm Murder.
Statistics show that people with anti-social personality disorder are often involved in crime, and they are also more likely to bear a tattoo than the rest of the population. The reason for this is unknown, but the tattoo can be a useful way of identifying these people. Indeed, this may be why criminals on parole sometimes can be identified through their tattoos if they run into more trouble. Often an ex-convict will have a tattoo bearing his name, his street name, or the name of a loved one. If he carries a gun, he may reveal this through a tattoo of the weapon. Wearing a tattoo may be a part of gang and criminal culture. For some people, the tattoo is an important part of belonging and of intimidating others. Certain gangs have distinctive tattoos. In California, the CALGANG database stores data on gang tattoos. This is a useful resource for the investigator who finds a tattoo on a corpse suspected of being the victim of a gangland killing or similar incident.
In Florida, a database has recently been created which includes around 372,000 tattoo records. All of these have been found on examination of criminals
SEE ALSO Identification; Profiling.