The impact of body refrigeration on decomposition and postmortem interval estimation

Estimating the postmortem interval (PMI) is a critical component of forensic investigations. Refrigeration is routinely used to slow or halt decomposition prior to autopsy; however, its impact on PMI estimation using total body score (TBS) and entomological methods remains insufficiently understood.

This study used ten domestic pig (Sus scrofa domesticus) carcasses (20-40 kg) decomposed under controlled conditions. Two controls were included: one remained unrefrigerated for 17 days and one refrigerated for 17 days. Eight experimental carcasses decomposed subaerially for 4, 7, 10, or 13 days before being refrigerated for four days, simulating standard forensic practice. Daily TBS, body and ambient temperatures, and accumulated degree days were recorded. PMI estimates were calculated at the end of both the subaerial and refrigeration periods using TBS and entomological approaches.

PMI estimates were most accurate when calculated prior to refrigeration, with 100% accuracy for both TBS (using body temperature) and entomological methods (using ambient temperature). Accuracy decreased following refrigeration to 75% for both methods. In inaccurate cases, refrigeration consistently led to PMI overestimation.

These findings indicate that refrigeration negatively affects the accuracy of PMI estimation using both TBS and entomological methods. Consequently, PMI should be estimated prior to refrigeration wherever possible to improve forensic accuracy.