One further comment and I will probably leave it for the evening.
Now that I know she was found naked, and taking that fact together with other facts, I have come to the provisional conclusion that the killer is somebody she knew. It must be somebody very close to her.
The only thing that could change my mind about that and consider a predator killing (apart from somebody confessing) is if it turns out that blood was found on any of her upper clothing - shirt, jacket, maybe bra.