Blowfly maggots as the physical evidence for forensic cases / Rumiza Abd Rashid … [et al.]

Estimation of post mortem interval (PMI) is one of the most crucial matters in death investigation and entomological specimen has widely been applied to determine PMI after 72 hours of death. This is done using the oldest blowflies larvae found and from the succession pattern of insects that colonize the dead remains. Thus, the uses of blowflies in forensic cases are crucial. The most common blowflies in Malaysia are Chrysomya megacephala and Aechotandrus rufifacies. Blowflies arrived and oviposited on the body minutes to the death as the odour released from autolysis process happened in carcass, attracts them. The eggs then grew to feeding larvae that feeds on the dead remains, until it reaches maturity. Larvae that feed on tissues of an individual who had taken drugs or poison while the person is still alive, will ingest the substance as well as its metabolites, proving that the drugs had accumulated in the body. In addition, the current situation of criminal cases nowadays, involved the use of firearm. Forensic investigation of such cases requires physical evidences to be collected at the scene of crime. In an extreme condition, when the bullet case is not found and the dead body is in active decomposition stage, blowfly maggots obtained from dead remains are potential in aiding forensic investigation. Our laboratory studied the presence of several toxins which were malathion, paraquat, gasoline, paracetamol and ketum extracts, along with gunshot residue (GSR), to determine the effects of all the toxins and GSR in development rates of blowflies, Chrysomya megacephala and Aechotandrus rufifacies, in which the presence of toxins may affect the estimation of PMI. We were also exploring the potential of blowfly samples to be applied in forensic investigation in detecting toxins and GSR. From our findings, it showed that the presence of malathion, paraquat, gasoline, paracetamol, ketum extracts and GSR in blowflies system affected the development rates of both flies. In real intoxication and shooting cases involved on decomposed remains, estimation of the correct PMI using larvae samples should consider the duration delayed and accelerated on the blowflies’ development. We also found that the presence of active components of toxins studied from the blowfly samples, proving the potential of blowfly samples to be applied in investigation. As a conclusion, blowflies of C. megacephala and A. rufifacies are suggested as important physical evidence in forensic investigations.