The hidden signature: Exploring the forensic science of lips impressions

Lipstick stains are one of the trace evidences which can be found at a crime scene. They are easily transferable and, like other forms of evidence, can provide a link between a suspect and a victim. Although even the unambiguous results of the lipstick stains examination do not constitute conclusive evidence of a crime, the information obtained may be useful as an aid to an investigation or as corroborative evidence. The biological phenomenon of systems of furrows on the red part of human lips was first noted by anthropologists. R. Fischer was the first to describe it in 1902. The shape of creases on the lips has distinct features like fingerprints. Cheiloscopy is a forensic investigation method that deals with identification of humans depending upon the on lips traces. According to the Federal Bureau of Investigation, lip prints, which are similar to fingerprints, palm prints, and footprints, can be used as a positive means of identification. The lip prints can also give other details such as cosmetics used, habits, occupational qualities and the pathological changes of lips. OBJECTIVES: This article's main goal is to describe the role that lipstick stains play in forensic science and how they can be used to identify a person. Different forms of expected and well-known sophisticated analyzing methods include gas chromatography mass spectrometry, thin layer chromatography (TLC), and high-performance liquid chromatography (HPLC). Raw lipstick and stains have been examined using spectrometric techniques such as neutron activation analysis (NAA), Raman spectroscopy (RS), and ATR-FTIR. Raman spectroscopy has been shown to be a useful tool for distinguishing and identifying lipstick samples. FTIR spectroscopy is another extensively used technique for examining lipstick stains. It is a non-destructive technique that yields rapid, precise examination of a small sample size. Using the proper methodology and analytical procedures is crucial for producing reliable results. Lipstick stains may be a useful evidence for identifying criminals. Identity can be established by a combination of methods which makes the identification procedure relatively flawless.