Entomological evidence in a case of a suicide victim by hanging: first collaboration between entomologists and forensic police in north-eastern Brazil

Peculiarities associated with the site and type of death impact the interpretation of entomological evidence in forensic investigations. We investigated the diversity and time to emergence of necrophagous species associated with a hanged cadaver in a city exposed to high levels of homicide in Brazil. Six species of four families of Diptera (Calliphoridae, Fanniidae, Muscidae and Sarcophagidae) colonized the corpse, of which Chrysomya albiceps (Calliphoridae) corresponded to 97% of all emerged adults. We provide supporting evidence for the record of Fannia pusio (Fanniidae) and for Hydrotaea aenescens (Muscidae) as colonizers of human cadavers. The time elapsed from collection of larvae until emergence of adults varied from 8 days (Chrysomya megacephala) until 19 days for F. pusio. A higher density of maggots occurred on the soil immediately below the cadaver when compared with the body. The use of time of development of both C. albiceps and C. megacephala provided similar estimations of the minimum post-mortem interval and suggested that death occurred approximately 36 hours prior to the discovery of the body. This case provides a novel collaboration between entomologists and forensic police in north-eastern Brazil and reinforces the importance of Fanniidae as a forensically important group in medico-legal investigations.