Catherine: Did you do a wet mount?
Doc Robbins: Sure did. Found motile sperm in the vaginal cavity.
Catherine: Well, Warrick found several used condoms at the scene. Killer must have run out, and started riding bareback.
Doc Robbins: Eh, I'm not sure he rode anything at all. There's an absence of trauma in the vaginal cavity.
Catherine: Enough to rule out rape?
Doc Robbins: Yeah. The semen was found at a depth not indicative of penile penetration. In this case, only a couple inches in.
Catherine: Maybe that's all the killer had to work with.