Considering the 'experts' said in all likelyness the piece of skull fragment found was human, her blood was found in the cottage and he was also an experienced abbatoir worker, it's possible that there's nothing left to find
I can see him doing a deal over the body though, I would be surprised if he ends up on the list of whole life tariffs, especially considering his body count is the grand total of one. He's in for a long stretch and I doubt' theyll let him out without a body which puts the ball firmly in his court.
Life in a VP wing for him hopefully will go insane or die of a prolapsed arse after being bummed to death. Normally one for cracking sick jokes about stuff like this for once totally shocked about the disapearance.