Latent lip prints: How far a link to the suspect?

Abstract

Background: Conventional lipsticks produce a lip print that can easily be studied, i.e. the visible lip print. Persistent lipsticks, on the other hand, do not leave visible prints and can thus be overlooked at the crime scene. This study aimed to evaluate the efficacy of chemical developers at the crime places as well as the importance of persistency of these lipsticks at different surfaces. Materials and Methods: As print vehicles, this study used white ceramic, cotton fabric, transparent glass, dark green glass, and white tissue paper. A lysochrome dye like Sudan III, fingerprint black and gray powders were used to develop the latent lip prints. The lip prints of the volunteers were left to dwell for different periods, untouched, and were later developed using these developers. Results: The results of this study show that identifiable lip prints can be obtained up to 30 days after being produced. Fingerprint powders and Sudan III work best on smooth and non-porous surfaces. Developing latent lip prints at the crime scene may provide an important focus of transfer not to be overlooked. Conclusion: Fingerprint powders can be used to develop the invisible lip prints and can significantly contribute in catching the suspect in criminal court cases. The presence of latent lip prints at the crime scene should be considered as a means of identification in the court of law.