The meaning and classification of tattoos in the context of their suitability to identify corpses of unknown identity

Aim of the study
To present the most popular types of tattoos, their meaning and classification, and to assess the suitability of different forms of tattoos in the process of identification of corpses of unknown identity.

Material and methods
The tattoos found on 729 cadavers who underwent post mortem examinations at the Department of Forensic Medicine in Warsaw in the years 2012–2015 were analyzed. The tattoos were photographed and identified in terms of their meaning domain and classified into groups.

Results
Tattoos belonging to all groups were found, according to the most popular tattoo classification, which is based on their nature and includes: criminal and prison tattoos (defining the prison hierarchy, criminal profession as well as intentions and goals, erotic tattoos, environmental, penitentiary), military and artistic. The novel classification, focusing on the utility of certain kinds of tattoos for identyfying corpses of unknown identity, was also developed. According to the above mentioned classification the following kinds of tattoos are distinguished: individual (artistic), group (e.g. penitentiary – indicating the fact of being imprisoned in a penitentiary institution or belonging to a “prison kites” subculture, or presenting criminal profession; group confined tattoo (indicating a staying in a specific penitentiary institution), group tattoo with individual data (indicating the fact of staying in a penitentiary institution as well as dates of imprisonment), and others (e.g. names of relatives, military tattoo, etc.)

Conclusions
Analysis of individual types of tattoo can accelerate the process of identification of the cadavers. The proposed classification allows to quickly determine whether a particular tattoo can be helpful in initial individual identification (in the case of individual tattoos) or whether it can be used to reduce the group of people considered (in cases of different types of group tattoos).