Estimation of the Time Since Death

Abstract

The estimation of the time since death is a practical task in daily forensic casework. The estimation should be as precise as possible but first of all reliable. With increasing postmortem interval the estimation will be less accurate. The postmortem changes which are used for estimating the time since death are completely different in nature. The progression of postmortem changes is influenced by many internal or external factors, mainly the ambient temperature. The best investigated method of estimating the time since death is postmortem body cooling described by the two-exponential model of Marshal and Hoare and the nomogram method developed by Henssge. The rectal temperature time of death nomogram should be used as the leading method for estimating the time since death. However, in the best case, a precision of ±2.8h around the mean value (95% confidence limits) can be achieved. Therefore other methods of death time estimation should be used to narrow down this range further (electrical and mechanical excitability of skeletal muscles; chemical excitability of the iris; lividity and rigor mortis). Chemical methods and gastric contents are only of limited value in estimating the time since death. Putrefactive changes can be used for bodies recovered from water if the water temperature is known and was relatively constant over a long period.