Reconstruction of postmortem interval from evaluation of decomposition rates and patterns based on modes of death using porcine models

Abstract

Background and aim: Decomposition patterns and rates are important in forensic taphonomy for estimating postmortem interval and determining the hidden mode of death. The current research documents decomposition rates for four different modes of death using domestic pigs as proxies for human remains in Northern Cross River State, Nigeria.

Methodology: Four porcine specimens were subjected to different modes of death (burning, strangulation, poison and blunt force trauma) and placed in open earth surface environment. Physical and chemical postmortem changes were monitored over 30 days, incorporating assessments of total body score (TBS), accumulated degree days (ADD), and insects colonization.

Results: Distinct variations in the rates of decomposition between different modes of death. Fire-induced rapid early decomposition was observed among burnt carrion as a result of desiccation of tissues brought about by fire. The toxic environment probably brought about by insect mortality delayed decaying in poisoned carrion. Blunt trauma carrions decomposed more quickly than the strangulated and drowned specimens, while the environmental exposure accelerated tissue breakdown. Insects were a principal agent in the degradation of soft tissues, whose species diversity and activities differed between modes of death. Analyses of the soils demonstrated a modification of the physicochemical characteristics after decomposition fluids had acted, especially nitrogen enrichment, but were indicative of the importance of the role of soil in modulating decay rates.

Conclusion: These findings present foundational insights into the advancement of forensic taphonomy and contribute to the enhancement of medico-legal investigations in Nigeria and other resource-constrained regions.