The only thing that makes me think she wasn't in a hit & run, is that if there was blood on the road or skid marks, then the police, the search parties and dogs would have noticed it.I have no knowledge of the area unfortunately.
Just trying to understand why that particular car seems to be singled out.
Maybe they struck her and they picked her up?
Could she have succumbed to injuries while in the car and they panicked?
I have no idea at all, just speculating why this vehicle may be involved or have information.
JMO
Although no guarantee there would be blood, I suppose.