Using Estimated On-Site Ambient Temperature Has Uncertain Benefit When Estimating Postmortem Interval

Abstract

The forensic entomologist uses weather station data as part of the calculation when estimating the postmortem interval (PMI). To reduce the potential inaccuracies of this method caused by the distance between the crime scene and the meteorological station, temperature correlation data from the site of the corpse may be used. This experiment simulated the impact of retrospective weather data correction using linear regression between seven stations and sites in three climatic exposure groups during three different seasons as part of the accumulated degree days calculation for three necrophagous species (Diptera: Calliphoridae). No consistent benefit in the use of correlation or the original data from the meteorological stations was observed. In nine cases out of 12, the data from the weather station network limited the risk of a deviation from reality. The forensic entomologist should be cautious when using this correlation model.

Decomposition pattern and insect colonization in two cases of suicide by hanging

“…Such differences and the missing retrospective corrections may explain in the present case studies the inaccuracy of the assigned TBS values in predicting ADD. However, currently it is controversial the benefit of using retrospective corrections for short and long-term correlations between site-specific and weather station temperature data [ 25 , 37 ]. It has been also observed that scoring scales and regression equations derived for predicting ADD seem to be of little help in forensic practice [ 38 , 39 ] because of the so many factors affecting human decay and insect colonization among which irregular decomposition and mummification need to be taken into account [ 35 ].…”

Family Calliphoridae: An Integral Part of Postmortem Interval Estimation

“…Lucilia caesar was found to have the shortest maximal adult arrival time and Calliphora vomitaria to have the longest maximal arrival time [11]. If ambient temperature of the scene is unavailable, or if the examiner fails to measure it, information can be collected through weather station data [12]. However, temperature fluctuation is minimal indoors because of insulation and use of thermostats.…”

“…Calliphoridae participate in oviposition in temperatures ranging from 5°-38°C, but rarely lays eggs below 10°C [11]. Understanding how temperature affects development and oviposition and knowledge of ambient temperature where corpse was discovered can aid in the PMI determination [12]. Cocaine and ketamine were found to accelerate development [13,14], while morphine, heroine, and barbiturates delayed development [4,13].…”

A mathematical model applied for assisting the estimation of PMI in a case of forensic importance. First record of Conicera similis (Diptera: Phoridae) in a corpse

“…Currently, to ascertain the temperatures that occur in the place where a corpse is discovered, a simple process is applied based on the calculation of a regression equation from the relationship between internal and external data [5][6][7][8][9]. However, when a dead body is buried or found in a closed habitat or in dark conditions, this extrapolation does not always reflect reality.…”