Lip Print

Lip Print Identification In Criminal Investigation

Just like fingerprints, lip prints can be used to identify a person. The wrinkles and grooves on our lips form characteristic patterns, which are unique and do not change during our lives. Hereditary factors may have an influence on these patterns. The lip prints of parents and children and those of siblings may have some similarities. It is also revealed that male and female lip print characteristics are distinguishable.

The study of lip print is known as Cheiloscopy, which deals with the identification of humans. It can be used in judicial setting and accepted by the court and the general scientific community to separate truth from untruth, especially in cases lacking other evidence. Traditional methods of personal identification include anthropometry, dactyloscopy, DNS finger-typing, sex determination, estimation of age, measurement of height, postmortem reports, and differentiation by blood groups. These methods are accepted by all investigators, while some of them have reservations about Cheiloscopy as a method of human identification.

One of France’s most famous criminologists, Edmond Locard recommended the use of lip prints as early as in 1932. LeMoyne Snyder, in his forensic manual Homicide Investigation (1950) mentions the possible use of lip prints in the identification of individuals. He represents an interesting case in which a woman was struck by a car striking her face on the left front fender of a car. The man who had been driving the car denied that he had hit that woman. A lip print was taken from the left front fender of the car. The print was matched with that of the woman and it was proved that it was the lip print of the woman who was hit in the accident. Consequently, the man was convicted.

In 1970, Japanese doctor Suzuki realized the importance of lip print identification, on the basis of Snyder’s book, mentioned above. He saw a great opportunity in the ideas of Snyder, and started to work on the classification of lip prints. He examined 107 Japanese females aged 20-36 and laid down the basics of a system which is still in use today. Santos in 1967 systematically classified lip print types. He divided the wrinkles and grooves on the lips into simple and compound types and sub-divided them into eight groups. Suzuki in 1970 after conducting the study on 107 Japanese women as mentioned above simplified the classification into five main types.

Modern forensic lipstick analysis relies on techniques such as microspectrophotometry, high performance liquid chromatography and energy dispersive x-ray analysis. These techniques may be destructive or they are not 100% trustworthy, and are not the best method for forensic investigations. However, the use of this technique can contribute to investigating criminal cases. What is more, today it is possible to extract DNA from fingerprints. This allows us to consider that invisible or latent lip prints may provide cell remains from which DNA can be obtained. It makes sense to improve Chelioscopy, which has the potential to be a very effective suspect identification tool in forensic investigations.