Young couple goes on van tour of US, boy comes back with van - no girl

Backpack and notebook belonging to Brian found in the area where human remains have been found. The area was underwater until recently. FBI agent said that this concludes the investigation. He didn't say that the body was Brian, but certainly sounds like it
I've heard it was a "dry bag" and I hope it at least was a waterproof backpack so that Mr. Survivalist's notebook is intact enough to read and hoping that he was at least honest in anticipation of his own death. I doubt it but who knows.