The development of a post-mortem interval estimation for human remains found on land in the Netherlands

Abstract

The decomposition process of human remains can be used to estimate the post-mortem interval (PMI), but decomposition varies due to many factors. Temperature is believed to be the most important and can be connected to decomposition by using the accumulated degree days (ADD). The aim of this research was to develop a decomposition scoring method and to develop a formula to estimate the PMI by using the developed decomposition scoring method and ADD.A decomposition scoring method and a Book of Reference (visual resource) were made. Ninety-one cases were used to develop a method to estimate the PMI. The photographs were scored using the decomposition scoring method. The temperature data was provided by the Royal Netherlands Meteorological Institute. The PMI was estimated using the total decomposition score (TDS) and using the TDS and ADD. The latter required an additional step, namely to calculate the ADD from the finding date back until the predicted day of death.The developed decomposition scoring method had a high interrater reliability. The TDS significantly estimates the PMI (R ² = 0.67 and 0.80 for indoor and outdoor bodies, respectively). When using the ADD, the R ² decreased to 0.66 and 0.56.The developed decomposition scoring method is a practical method to measure decomposition for human remains found on land. The PMI can be estimated using this method, but caution is advised in cases with a long PMI. The ADD does not account for all the heat present in a decomposing remain and is therefore a possible bias.

Keywords: Accumulated degree days; Decomposition phenomena; Decomposition process; Forensic science; Forensic taphonomy; Post-mortem interval.

Fig. 1

The general selection of cases. TDS=total decomposition score, PM=post-mortem, PMI=post-mortem interval

Fig. 2

Body decomposition score 3.2.3: marbling

Fig. 3

Limbs decomposition score 3.2: grey to green discoloration

Fig. 4

Scatter plot of the total decomposition score vs. the post-mortem interval in days (n = 91)

Fig. 5

Plot of total decomposition score vs. log transformed post-mortem interval indoors. R ² = 0.670 (n = 79)

Fig. 6

Plot of total decomposition score vs. log transformed accumulated degree days indoors. R ² = 0.658 (n = 79)

Fig. 7

Plot of total decomposition score vs. log transformed post-mortem interval outdoors. R ² = 0.803 (n = 12)

Fig. 8

Plot of total decomposition score vs. log transformed accumulated degree days outdoors. R ² = 0.557 (n = 12)