Victims are usually the only witnesses to the crime, under great psychological stress upon reporting it, and sometimes motivated to distort the incident and conceal their own provocative behavior. Sexual offenses are either premeditated or spontaneous, which determines the sequence of events and the extent of violence. A significant factor is whether the victim and offender are strangers or known to each other. Evidence collection involves examination of the victim's body and clothing with special attention to signs of violence and traces of the offender's hair, sperm, blood, etc. The nature of this type of evidence requires that it be obtained as soon after the act as possible and properly collected and preserved. Because many of the sexual assault and rape incidents reported to the police turn out to be partially contrived or exaggerated, interrogators must be especially attentive to the person making the charges and her motivations. The accuracy of the story is easiest to verify if the victim reports the assault immediately after its occurrence. In many true rape incidents, victims delay the report because of shock, humiliation, the need to clean themselves and consult their families. It is essential to obtain information on the victim-offender relationship. The victim should also be medically examined. Ease of arresting the offender depends on whether his identity is known and on how much time has elapsed. Often an immediate arrest can elicit a confession while at court most rape offenders deflect their guilt and make counteraccusations. If insufficient evidence has been obtained, the trial of the case pits the offender's word against that of the victim. Supplied are 14 references and 25 footnotes.