Freshwater invertebrates and Wagner's parsimony method (WPM): Tools for the submersion time estimation of a cadaver found in a natural aquatic environment. Description of a sampling protocol

Summary The forensic investigations are generally very difficult when a body is discovered immersed for an ignored period in freshwater. Due to long periods of immersion and a high level of putrefaction, the estimation of the time since death is problematic. Classical forensic entomology is based on existing links between necrophagous insects and the state of decomposition, in order of appearance of necrophagous insects on the cadaver. This science does not allow a pertinent evaluation of the time since the death for a crime scene technician. It is indeed impossible to reach any conclusions based on the underwater colonisation process once the cadaver has resurfaced. The purpose of this work was to analyze from February 2001 to October 2002, the different cases of cadavers’ discoveries in order to isolate pertinent bioindicators. We created a simple but effective sampling protocol to get a real solution to the problem of estimating the post mortem submersion interval (PMSI) of a cadaver found in lotic or lentic water.