Forensic taphonomy in an indoor setting : Implications for estimation of the post-mortem interval

Abstract: The overall aim of this thesis was to determine if and how taphonomic data can be used to expand our knowledge concerning the decompositional process in an indoor setting, as well as adapting scoring-based methods for quantification of human decomposition, to increase the precision of post-mortem interval (PMI) estimates.In the first paper, the established methods of Total Body Score (TBS) and Accumulated Degree-Days (ADD) were investigated in an indoor setting, with results indicating a fairly low precision. The PMI was often underestimated in cases with desiccation and overestimated in cases with presence of insect activity. This suggests that the TBS method needs to be slightly modified to better reflect the indoor decompositional process.In the second paper, a novel method for PMI estimation was developed using histological assessment of decompositional changes in the human liver. The scoring-based method created, the Hepatic Decomposition Score, was a statistically robust way to quantify the degree of decomposition, with the potential to improve the precision of PMI estimates.In the third paper, the indoor decomposition process was further investigated regarding microbial neoformation of volatiles in relation to the degree of decomposition and the PMI. A higher decomposition degree was observed in cases with neoformation (i.e., presence of N-propanol and/or 1-butanol in femoral vein blood) than in cases without signs of neoformation. Microbial neoformation may be an indicator of decomposition rate, which may make it possible to improve the precision of PMI estimates based on the TBS/ADD method.In the fourth paper, a novel constructed Bayesian framework allowed a qualified estimate of PMI based on observed taphonomic findings. This framework provided a unique possibility to report results, express the uncertainties in assumptions and calculations, as well as to evaluate competing hypotheses regarding PMI periods or time of death.Taken as a whole, the results indicate that using taphonomic data derived from an indoor setting could improve scoring-based methods, as well as highlighting benefits of incorporating such data into a Bayesian framework for interpretational purposes and for reporting PMI estimates.