As I was looking at the pic I saw the fence and with a velocity above 55 mph it could happen. My guess is she was above that speed to cut her so precise. About 144 mph is about as fast as a body will fall. There would be more splatter if she was at that speed.
It's very unlikely it was an automobile or even a fall that did this, given the fact there doesn't appear to be any other injuries to her, at least none that I can see. The most likely culprit would be someone cut her in half, as she appears posed to some degree. Also, too, if it had been a shock-force injury, you'd see much more of her innards pulled out. This looks to much of a clean separation for it to have been from a fall or automobile collision.
