A body farm is used in the study of forensic anthropology: the study of human decomposition that occurs after death. Various forensic disciplines benefit from the studies done through a body farm, among them law enforcement, medical examiners and crime scene investigation. The research assists examiners in developing a better understanding and developing better methods of determining what the actual time of death was. The Federal Bureau of Investigation holds training courses at the University of Tennessee Body Farm, in order to expose agents to crime scene simulations where they have to dig up bodies. There are two such facilities in the United States.
http://en.wikipedia.org/wiki/Body_Farm