Estimating Postmortem Intervals of Human Remains Recovered in Mid-Western Waterways: A Test of Terrestrial and Aquatic Body Scoring Methods

In attempt to determine postmortem intervals (PMI), forensic investigators often rely on observed amounts of postmortem taphonomic alterations of the human body. Research has been conducted in an attempt to understand and predict the sequence and rate of human decomposition using total body scoring methods as well as accumulated degree days (ADD) (Megyesi et al. 2005). While most research focuses on methods of decomposition scoring in terrestrial environments, Heaton et al. (2010) devised a method to aid in the prediction of PMI and postmortem submersion intervals (PMSI) in an aqueous environment. Using 73 forensic cases collected from the Hennepin County, MN, Medical Examiner’s Office, La Crosse, WI, Medical Examiner’s Office, and the Manitowoc County, WI, Medical Examiner’s Office, this study demonstrates that aquatic taphonomic alterations do not always occur in a sequential pattern due to a plethora of variables, such as water temperature. The data were split into three categories according to known ADD. Using both the Megyesi et al. (2005) and the Heaton et al. (2010) decomposition scoring methods, cold water submersion of a human body can produce varied results and the inability to accurately predict PMI and PMSI. Those forensic cases with the shortest PMSI also show a low accuracy rate of predicting PMSI. Both the Megyesi et al. (2005) and the Heaton et al. (2010) total scoring methods resulted in more accurate PMSI prediction for those cases with ADDs between 26°C and 99°C. This study demonstrates the demand for more accurate decompositional scoring methods and the need for further exploration into the study of the effects of cold-water temperatures on the taphonomic process of the human body