Assessment of post-mortem interval based on post-mortem changes and entomological findings

Abstract

The post-mortem interval (PMI) is the time elapsed since the death of an animal. The assessment of PMI leads us to determine the manner and circumstances of death, and in some cases, aids in finding the offender. This article presents a case of a suspected crime of killing and torturing animals, and apart from thecauseofdeath,itwasnecessarytodetermine the post-mortem interval. The determination of PMI was based on the assessment of postmortem changes and entomological findings. After death, the animal body undergoes certain changes resulting from the cessation of vital functions and cell death. These changes are irreversible and progressive, leading ultimately to complete decomposition of the body. During the investigation, signs of putrefaction and the absence of postmortem muscle rigidity were advanced, and it was impossible to precisely establish PMI based solely on postmortem changes. In cases where post-mortem insect colonization is present, it is possible to establish PMI by determining insect type and development stage, and the influence of environmental factors on their development. According to the available entomological evidence and observed morphological characteristics, the larvae were classified to belong to the fly family (Calliphoridae), and determination was made to the species Calliphora vicina with a given level of certainty. Namely, due to the inability to collect and store samples, it was not possible to establish the exact species determination based on morphological and molecular analyses. Nevertheless, this finding contributed significantly to PMI assessment and helped to solve the case.