Association of commingled human skeletal remains by their elemental profile using handheld laser-induced breakdown spectroscopy

When multiple sets of skeletonized human remains exist in the same context, they can become commingled due to multifactorial circumstances that affect the postmortem environment. Numerous techniques exist for reassociating commingled skeletal remains (e.g., visual pair-matching, and osteometric pair-matching); however, the scale of commingled skeletal assemblages influences the effectiveness of these approaches. Laser-Induced Breakdown Spectroscopy (LIBS) has recently been proposed as a rapid technique for obtaining elemental signatures from skeletal elements of multiple individuals and then reassociating those elements with their correct individual. This study evaluates the potential of portable LIBS as a useful tool for reassociating commingled human skeletal remains in forensic contexts. In this study six skeletons drawn from the donated skeletal collection at the Florida Institute for Forensic Anthropology and Applied Science, at the University of South Florida, were used to assess whether LIBS data could be used to reassociate multiple skeletal elements from the same individual. LIBS data were collected at 206 anatomical locations from 28 individual bones across each skeleton in the sample. LIBS data were reassigned to their individual with an accuracy of 91 % using quadratic discriminant analysis of dimensionally reduced data (via principal component analysis). The study demonstrates that portable LIBS has potential for reassociating commingled human skeletal remains from forensic contexts.