Estimation of Time Since Death of Bodies Above Soil Surface in A Guinea Forest-Savannah Vegetation of Nigeria Using Visible Post Mortem Changes

Abstract

Background: Forensic taphonomy is the use of decomposition timeline estimation to unravel mystery behind time of death confirmation in homicide cases involving the law court. The Guinea forest-savannah vegetation is one of the vegetations in Nigeria characterized by short trees, grassland, very hot temperatures almost round the year, speedy wind, etc. It has two distinct seasons – rainy and dry seasons. This study aimed at investigating the visible post mortem changes of domestic pigs (Sus scrofa domestica) in a Guinea forest-savannah vegetation of Nigeria so that it can be used to estimate time since death of bodies on the soil surface. Methods: A stratified random sampling technique was used to select two male and two female matured domestic pigs from a private pig farm located close to the research facility. The visible post mortem changes were observed daily (morning, afternoon and evening) for 49 days. Results: Four stages of decomposition were identified namely fresh, bloat, active decay, and advanced decay stages. Mummification process started at the sixth day post mortem which slowed the rate of decomposition, and prevented the animals to completely skeletonize within the study period. Extreme atmospheric temperature was the major factor that aided the mummification of the animals. Conclusions: Decomposition of domestic pigs in this region accelerates at the early hours of post mortem, and subsequently slows down due to extreme climatic conditions. In addition, it takes carcasses on the soil surface more than 49 days to completely skeletonize due to its vegetative factors. This implies that most crime investigations carried out in this region must take into account the climatic conditions before estimating the time of death. KEYWORDS: Crime investigation, Decomposition timeline estimation, Forensic taphonomy, Mummification, Stages of decomposition, Visible post mortem changes.

A synthesis of carcass decomposition studies conducted at a tropical (Aw) taphonomy facility: 2013–2022

“…However, the decomposition stages ascribed to these carcasses lagged behind the stages at the Chaminade facility by several days. A similar phenomenon was observed in studies from Nigeria [ 79 , 80 ] where TBS in Okuku, Cross River State and Ekwulumini, Anambra State were similar to the TBS from the Chaminade facility. In contrast, the decomposition stages at these Nigerian sites occurred several days after the stages observed at the Chaminade facility.…”

The smell of death. State-of-the-art and future research directions

“…One such change is the onset of pallor mortis . This most rapid effect is caused by the cessation of blood flow through the skin capillaries typically occurs within 20 min postmortem ( Schäfer, 2000 ; Onyejike et al, 2022 ). Subsequently, ‘the cooling of the body to ambient temperature’ defined as algor mortis proceeds ( Schäfer, 2000 ; Gonçalves, 2022 ; Onyejike et al, 2022 ).…”

“…This most rapid effect is caused by the cessation of blood flow through the skin capillaries typically occurs within 20 min postmortem ( Schäfer, 2000 ; Onyejike et al, 2022 ). Subsequently, ‘the cooling of the body to ambient temperature’ defined as algor mortis proceeds ( Schäfer, 2000 ; Gonçalves, 2022 ; Onyejike et al, 2022 ). Taking into consideration the opacity of the cornea, the absence of ocular changes indicates that death happened within the preceding 2 hours ( Wróblewski and Ellis, 1970 ; De-Giorgio et al, 2021 ).…”