SB has said he "officially" became involved on 9/11, but I'd be curious to know if he was contacted "unofficially" before that, as well, regarding BL/GP.
Here's my hangup. If we believe that BL killed GP on 8/27, then he really did hike/hitchhike telling stories for alibis. Why did he not follow through with that? Why not continue on with his story of having been away from her? And we know for a fact, via the FBI, that he sent false texts between GP's phone and his phone after she was dead, to try to fool LE, and maybe he used her debit cards for the same purpose. He didn't follow through on that ploy, either.
Then we have multiple confessions, which don't necessarily match one another. Why not follow through on any of those? And the story he chose to leave the world with, upon his death, was complete nonsense.
It feels to me that from the very moment he killed GP, his mind was discombobulated. He was unable to think anything through enough to go with it. He had to know that her family would start looking for her sooner rather than later. And especially if his parents were offering assistance helping him get away, he could have followed through with that. But he chose another way out. IMO, this was never someone who thought he was going to get away with it.