I suppose the car seen earlier in the day could have been anyone. This camp wasn't totally isolated from the real world, so it may have belonged to a neighbor or someone fishing in the creek.
Here's a profile I didn't see in the link posted earlier so I'll post it here.
This is an article from Fox News in 2008. DNA testing was inconclusive.
This link explains the location of the tent and that it was one of few that didn't have a counselor sleeping in it. It's guessed that the perb must have known this.
I get the feeling we haven't found half the stuff out there regarding this case. It'll help to find out what those books say. Now I'm all interested in it.
When I am through with the books (I ordered both) I will be happy to send them to you if you like...