blowflies

In homicide cases, knowledge about time of death is important as it directs police investigation towards the discovery of authorship, including or excluding suspects of a crime, and determining nature of death. In Brazil, entomological evidence is still neglected by official forensic organizations and for this reason cases using insects to estimate post-mortem interval (PMI) are still rare. Dipteran specimens collected and analyzed by the staff of Criminalistics Institute (CI) from São Paulo State, Brazil, made it possible to elucidate circumstances of the death, including suspects to the crime scene, in five occurrences involving discovery of cadavers. In all cases, blowflies were collected and were identified as belonging to species Chrysomya albiceps (Wiedemann, 1819), Chrysomya megacephala (Fabricius, 1794), Chrysomya putoria (Wiedemann, 1830), Hemilucilia semidiaphana Rondani, 1850 and Lucilia eximia (Wiedemann, 1819) (Diptera: Calliphoridae), while only in one case Sarcophagidae (Diptera) flies were also collected. PMI estimate was calculated taking into account laboratorial developmental rate data of mentioned species on the environmental temperature on which bodies and insects were exposed, along with comparisons to field research previously conducted in those areas. Based on larval age and behavior, the course of the investigation had changed, pointing to the crime author (case I), as well as the nature of the crime (cases I-III) and associated suspects to the criminal act (cases IV-V). Results show how promising is the use of entomological evidence during investigations of violent deaths.