I gotta say, the more I look at the pictures of the phone that was burned, the more I wonder if this is some kind of hoax and someone is trying to cash in on the whole Note 7 thing. ...
The back tells us a lot more, however. ...The burn on the back looks oddly specific, with clearly defined edges (which again conveniently cover up some obvious ID marks), and the rest of the back of the phone looks in fine shape, not like a phone that "exploded". It's also strange how the internals that are visible, which I can't be certain what they are, but it looks to be a portion of an antenna and some other metallic parts, don't really look all the damaged, they are still pretty shiny and stuff, not at all like they were part of an "explosion" of the battery pack.