Modelling time-since-death in Australian temperate conditions

Studies of time-since-death (TSD) with respect to decomposition processes have been limited in scope. Most research has focused on qualitative descriptions of decomposition, which are too broad to be of use in recent death investigations. This study developed a degree of decomposition index (DDI) by quantifying stages of decomposition for individual body elements. Two Sus scrofa (White hybrid pigs) were allowed to decompose undisturbed on the ground surface, one in full sun and the other in semi-shade, between November 2006 and January 2007 in the Canberra region, Australia. The results of the regression modelling suggests that TSD accounts for the majority of variation in decomposition (using the DDI), while variations in macro-environment (sun versus shade) were not significant contributing factors. It is concluded that quantifying decomposition is an effective method of estimating TSD, which negates variable environmental effects on the decomposition process. The implications for forensic investigations of recent deaths include the potential to provide an improved estimation of TSD at the time of body recovery. There are also important implications for future research into decomposition and for forensic anthropology in general.