A general approach for postmortem interval based on uniformly distributed and interconnected qualitative indicators

Abstract

There are many qualitative indicators for postmortem interval (PMI) of human or animal cadavers. When such indicators are uniformly spaced over PMI, the resultant distribution may be very useful for the estimation of PMI. Existing methods of estimation rely on indicator persistence time that is, however, difficult to estimate because of its dependence on many interacting factors, of which forensic scientists are usually unaware in casework. In this article, an approach is developed for the estimation of PMI from qualitative markers in which indicator persistence time is not used. The method involves the estimation of an interval preceding appearance of a marker on cadaver called the pre-appearance interval (PAI). PMI is delineated by PAI for two consecutive markers: the one being recorded on the cadaver (defining lower PMI) and the other that is next along the PMI timeline but yet absent on the cadaver (defining upper PMI). The approach was calibrated for use with subsequent life stages of carrion insects and tested using results of pig cadaver experiments. Results demonstrate that the presence and absence of the subsequent developmental stages of carrion insects, coupled with the estimation of their PAI, gives a reliable and easily accessible knowledge of PMI in a forensic context.Electronic supplementary materialThe online version of this article (doi:10.1007/s00414-016-1520-3) contains supplementary material, which is available to authorized users.

Post-Mortem Interval Estimation Based on Insect Evidence: Current Challenges

“…Such data are essential to use insects that colonize cadavers late in decomposition, as their PAI may be longer than the development interval, and to get meaningful PMI it may be necessary to combine insect age with the PAI [ 5 , 11 , 103 ]. PAI may also support estimates of maximum PMI when insect evidence is absent [ 104 , 105 ]. PAI may be estimated using the temperature models for PAI [ 106 ].…”

“…Forensic entomologists developed several methods for the estimation of PMI based on insect development [ 26 , 41 , 180 , 181 , 182 ] or succession [ 103 , 105 , 115 , 117 , 118 , 128 , 183 ]. As there are contemporary reviews of these methods [ 1 , 184 ], in this article I focus only on their validation ( Table 4 ).…”

Content Analysis of the Forensic Medical Assessment of Postmortem Interval

“…У протоколах огляду трупа на місці його виявлення не завжди були наявні відповідні виміри (температура навколишнього повітря, вологість, кількість шарів одягу на трупі, ложе трупа тощо), які могли б покращити точність оцінки ДНС. Впровадження цих вимірів у практику дозволить викори-стати новітні методи при дослідженні ДНС [29,30,31,32].…”

Forensic Medical Assessment of Morphological Changes at Different Postmortem Interval

“…Postmortem interval evaluation is still one of topical issues. Variety of approaches are being applied to define PMI, methods from different fields, such as forensic botany, genetics, entomology, biochemistry, microbiology [1][2][3][4][5][6][7][8][9][10][11]. But most of these methods are useful only in relatively short term after death [12].…”