Death caused by a deviate sexual act can present unique and often bizarre findings, both at the scene of death and in the pattern and type of injuries to the deceased. In such cases a close working relationship between the law enforcement investigators and the pathologist is important. It should be emphasized that natural deaths can occur during normal and deviate sexual practices, the majority of which are related to acute coronary artery insufficiency. Major deviate sexual practices include sadism, masochism, rape, homosexual practices, pedophilia, gerontophilia, voyeurism, pyromania, exhibitionism, bestiality, and necrophilia. Sadism is the attaining of sexual pleasure from acts of cruely or infliction of pain upon one's partner. It is usually associated with masochism, the desire to receive pain for the purpose of sexual gratification. Combining these practices is called bondage; death results from the use of chains, ropes, and belts which cause strangulation in many cases. Prostitution frequently involves sadomasochistic tendencies. Another subdivision of bondage, sexual asphyxia, includes those accidental deaths that occur during acts of perversion. The number of murdered rape victims remains relatively small although the incidence of rape is increasing in the United States. When sex crimes occur, they are usually a series of murders perpetrated by the same individual. Deaths resulting from male homosexual practices usually have a characteristic pattern both at the crime scene and in the injuries resulting from death. Pedophilia involves a sexual act occurring between an older individual and an individual of preadolescent age. The mode of death usually involves head injury or strangulation. Gerontophilia is the deviate practice of male sexual attraction to older persons of the opposite sex for sexual gratification. Victims generally sustain considerable injuries including bruises, lacerations, and facial bone fractures. Voyeurism, exhibitionism, bestiality, and necrophilia rarely result in death. Photographs and 15 references are included. For related documents, see NCJ 69731-40 and 69742-47.