Yeah, I think it's becoming more probable that he had some kind of helping hand. Although, it's still possible that he could have arranged for this rather than it being murder. Logistically, it would have been pretty difficult to get the job done by himself, within 15-30 minutes (assuming they were indeed checking on him), and within a pretty sparse cell without anything to hang from, really.
Hearing that he was attending 12-hour meetings with his lawyers and was reportedly optimistic bordering delusional prior to his death makes me think that it's more likely he was taken by surprise though.