Goren calls a wedding ring a "proof of life". A "proof of life" is not an inanimate object, like a ring. A "proof of life" is voice on the telephone, an image or video with some way to prove it was just taken and the person is in fact alive. A ring does not prove a person is alive or dead. It's just a ring.
When William is discovered at the fence, his hands are clearly handcuffed. Then in hospital, he tells the detectives he was "tied to the fence".
When Goren matches up the belt to the cut in the chain link fence, the scratches in the belt are in a V-shape like the fence. In fact, the scratches should be parallel and the same width apart as the distance between the cut ends of the fence.