Estimating minimum post-mortem interval in a Nigerian murder case using Chrysomya megacephala (Fabricius, 1794) (Diptera: Caliphoridae): The first use of forensic entomology

Abstract

Introduction: This paper presents the first application of forensic entomology in a murder investigation in Nigeria involving the remains of a 54-years victim, on January 9th, 2019 in a shaded wooded area in advanced decomposition, with no clear indication of the time of death. Objectives: To estimate the minimum post-mortem interval of a 54-year-old corpse recovered in the advanced decomposition stage using the blowfly Chrysomya megacephala and the Advance-Degree-day (ADD) method. Results: An autopsy report revealed multiple wounds to the forehead including a bullet hole. Dead embalmed dead maggots recovered from the body were identified as C. megacephala, and an accumulated degree-day model was used to estimate the minimum post-mortem interval. The findings revealed that the recovered larvae were still within the third-instar stage and had accumulated thermal energy between 58 hours (= 1.6 days, equivalent to 38.7 ADD) and 102 hours (= 2.8 days, equivalent to 68.0 ADD), suggesting that the body may have been exposed to insect activity between January 1st and 9th January 2019 after expanding the range to cater for some uncertainties. Conclusion: In this Nigerian murder case, forensic entomology used the calliphorid species C. megacephala to estimate the minPMI to be between 2 and 9 days before the body was discovered, which translates to 1st - 9th January 2019 after consideration of some uncertainties and limitations. This confirmed the crucial role that insects play in providing valuable evidence to complement forensic pathological findings in homicides when conventional methods failed. Notwithstanding difficulties with employing insect evidence in forensic investigations in Nigeria, the application of this modern forensic technique has the potential to aid in the resolution of many unsolved murder cases and expedite the delivery of justice. The ability of law enforcement agencies in Nigeria to use the potential of insects in criminal investigations can be improved through collaborations and training with professionals from diverse professions.