Age determination of a blood stain in a decaying shirt by entomological means.

Sarcosaprophagous insects have sense organs highly adapted for the detection of carcasses. Consequently, in summer these insects are usually the first to find dead human bodies. Often, when the police arrive at the scene of a murder, sarcosaprophagous insects and even their offspring are already present in the corpse in large numbers. It is possible to draw some conclusions about the date of the crime from the species composition of these insects and from the stage of development of their offspring. Since the pioneer work of Megnin’ (1894), entomological analyses have been used as medicolegal indicators in scattered cases. But success in the use of this method has been variable and, consequently, it has never reached the status of a standard criminological method. Since the time of Megnin, the necessary background information about the habits and life cycles of sarcosaprophagous insects has increased considerably. Thus it is nowadays far easier to draw accurate conclusions. However, application of this knowledge to the field of forensic science awaits the development of working methods as well as experience in the highly variable situations occurring in connection with crimes. In fact, many crimes occur in situations which do not correspond at all to the conditions in which laboratory tests or field investigations on sarcosaprophagous insects are performed. The purpose of the present paper is to add to experience in the field of forensic entomology by describing a case where the rearing of fly larvae from a bloody shirt afforded evidence about the date of a knifing.