What I found iffy about the story is that here this place is out in the middle of nowhere, evidently, but there are several people there at the time claiming to try to talk him out of it. At least that's the story they were able to conveniently give to the police as witness statements.

I would consider those people suspects, wouldn't you? Where did they come from? How did they know what he supposedly intended? Conversely, why isn't it considered that they just hefted him over onto the road below to be run over by a car just to make sure?