Forensic science and the crime scene examiner play an important part in the investigation of an alleged rape. Superficially, it may be regarded as simply a matter of identifying semen stains found at the scene and assisting in the collection of intimate body samples, in order to identify the assailant; however, the offence of rape has a quite specific legal definition, with some variation from jurisdiction to jurisdiction, that requires some form of sexual activity without consent and usually involving penetration. The penetration need not be vaginal; indeed, the victim does not have to be female, and ejaculation does not have to occur.