Changes in the morphometric characteristics of tattoos in human remains

Tattoos are secondary identifiers that can be used to provide a presumptive identity and provide information about a deceased individual to a case. Additional information may be available through the analysis of the visual presentation of tattoos. The aim of this study was to examine the morphological changes of tattoos during the decomposition of a human donor in an Australian environment. Using time-lapse cameras recording for 16 months, stills were extracted and tattoos were quantified using ImageJ. A full analysis was completed on three tattoos, while a fourth tattoo was partially analysed. The tattoos showed the most change in area during the bloat stage of decomposition, staying relatively constant in size for the remainder of the study. The detailed shape of the outlines showed the morphological effect of desiccation as part of decomposition and continued to change until the tattoo was no longer visible. Of the tattoos fully analysed, two became redundant as secondary identifiers on day 294, the other on day 333, all due to lack of visibility. This information is useful during investigations of unknown deceased persons; in this case, the stage of decomposition influenced the presentation of the tattoo