A 75-year-old disabled man was killed by a homosexual mental patient by the rectal insertion of a walking stick. The external examination of the body showed only four superficial tears in the skin of the anus. However, there was a 1 cm diameter full thickness perforation in the anterior wall of the rectum and the cause of death was the perforated rectum. The importance of the careful investigation into the circumstances of death, the background of the decreased, and the condition of the anus and rectum is discussed.