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Post-mortem interval estimation in the tropical climate of Southern Nigeria

NCJ Number
310630
Journal
Canadian Society of Forensic Science Journal Dated: 2025
Date Published
July 2025
Abstract

Post-mortem interval (PMI) estimation is the first step in the investigation of decomposing remains. The absence of locally derived methods, and a dearth of forensic experts, make PMI estimation difficult in Nigeria. This study aimed to assess decomposition rates in southern Nigeria and to derive formulae for PMI estimation by using quantitative variables, accumulated degree days (ADD) and total body score (TBS), using a pig model (n = 20). A longitudinal examination of TBS and ADD was conducted over 14 months, during the dry and wet seasons. Scatter plots between TBS and PMI, and TBS and ADD were used to show decomposition patterns and loglinear random-effects maximum likelihood regression was used to produce linear regression formulae for PMI estimation. Overall, decomposition progressed rapidly. Shorter PMIs were associated with more advanced decomposition when compared to studies in temperate regions. Despite similar average daily temperatures in the wet and dry seasons, there were marked differences in decomposition patterns between the seasons, with the wet season exhibiting more rapid decomposition rates. This demonstrates the importance of rainfall and humidity in decomposition rates. The derived regression formulae for ADD and PMI will provide a much-needed location-specific method for PMI estimation in Nigeria and regions with similar climates. (Publisher abstract provided.)

Date Published: July 1, 2025