Rape investigation is the procedure to gather facts about a suspected rape, including forensic identification of a perpetrator, type of rape and other details. The vast majority of rapes are committed by persons known to the victim: only five percent of assaults are perpetrated by a stranger according to one survey. Therefore, the identity of the perpetrator is frequently reported. Biological evidence such as semen, blood, vaginal secretions, saliva, vaginal epithelial cells may be identified and genetically typed by a crime lab. The information derived from the analysis can often help determine whether sexual contact occurred, provide information regarding the circumstances of the incident, and be compared to reference samples collected from patients and suspects. Medical personnel in the