A dead victim can offer physical evidence and information about the type of confrontation and assault that took place. She can still convey whether the killer used just enough force to subdue and then kill her, or tortured and brutalized her because her pain brought him pleasure. The signature aspect of the crime, perhaps posing or mutilating the victim's body, helps profilers determine the killer's fantasies and gain insight into the way his mind works. In sexual assaults, the account of a living victim can help authorities classify the type of rapist and link the offender to other crimes. Various aspects of the attack itself and the rapist's interaction with the victim can shed light on the rapist's personality.
Rapists differ in motive and treatment of their victims.
During a rape, interaction between the offender and victim usually includes a verbal exchange. The tone of that exchange is helpful to investigators. The rapist may use vulgar and abusive language, or he may fantasize that he's the woman's lover and pay her complements. He may also do what's known as scripting, meaning he'll tell the victim what he wants her to say. He may force her to use sexually explicit language and act as if she's enjoying the experience.