Estimation of Post Mortem Interval from Molecular identification of Necrophagous Insects on Human Corpses

Background: Estimation of post‑mortem interval (PMI) is a crucial component of medico‑legal investigation. Conventional methods based on post‑mortem changes become unreliable with advancing decomposition. Forensic entomology provides an objective and scientifically robust alternative; however, entomological data are region‑specific and limited from the Indian subcontinent, particularly Punjab. Objectives: To identify necrophagous insect species infesting human corpses in south‑west Punjab using molecular techniques, to estimate minimum PMI based on insect succession and development, and to evaluate the accuracy of entomological PMI in comparison with conventional methods. Materials and Methods: A descriptive observational study was conducted on 26 medico‑legal autopsies at Guru Gobind Singh Medical College & Hospital, Faridkot, between January 2023 and June 2024. Insect specimens were collected from bodies and divided into two sets: one for rearing to adulthood for life‑cycle‑based PMI estimation and another for molecular identification using PCR amplification of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Entomological PMI was compared with PMI derived from police records, eyewitness accounts, and decomposition changes. Results: Males constituted 88.46% of cases, predominantly aged 20–50 years. Most cases (88.46%) occurred between May and October, and 61.54% of bodies were recovered from outdoor locations. The bloat stage of decomposition was most common (73.08%). Molecular Identification of species included Chrysomyamegacephala, Sarcophagacarnaria, Muscadomestica, Luciliacuprina, and Dermestesmaculatus. Entomological PMI correlated with known PMI in 96.15% of cases, with discrepancies mainly in drowning cases. Conclusion: Forensic entomology supported by molecular identification is a reliable tool for estimating minimum PMI in decomposed bodies in south‑west Punjab. Development of regional entomological databases and incorporation of entomology into routine medico‑legal practice in India are strongly recommended