Well after watching all four episodes the last couple of nights, I think I'm more confused that ever.
I don't however, think Bradley Murdoch is responsible. I think he was someone who it was convenient to set up for it and the police would be only too happy to get a fairly high profile drug trafficker behind bars.
There are so many holes in Joanne's story, she was so defensive in interviews that on its own makes her seem suspicious.
I do wonder if she was involved in Peter's disappearance/death? Not that she did it herself, but arranged it with someone. Did she want to maybe leave the path clear for herself and the other guy she'd been seeing, though it does seem a very extreme way to go about it.
Realistically what would Bradley Murdoch have had to gain from killing Peter and (allegedly) disposing off his body, and how on earth would Joanne REALLY have been able to hide in the bush so that neither him (a native Aussie) or his dog were unable to find her?
Then you had the lawyer, who by his own admission had been dodgy as hell and was clearly a bit of a media whore.
The guy that was absolutely convinced he'd seen Peter afterwards and behaving somewhat oddly did seem very sure, and then there was the guy that Peter had previously worked with and who claimed that Peter had as good as told him that he was going to do that.
If Peter did do that then it must have absolutely destroyed his family. His poor Dad in particular looked like a broken man