4. Killer worked for UHC and/or is aware of 'unacceptable' (in his mind) practices. He acted as a whistleblower to remove the cause of the practices (in his mind) as well as to get attention on the situation.Good points.
As I see it--there are three potential motives for killing BT.
1. The killer has a loved one who was denied coverage.
2. The killer is part of a shadowy group, as you say.
3. The killer was hired by someone to kill BT.
Number 1 is Occam's Razor, but the most likely scenario is looking more unlikely in this case. Why? Because the killer is going out of his way to send messages. It's likely those messages are intended to send LE on a goose chase. But still, Number 1 can't be ruled out.
Number 2 is in the running because there are strong indicators that the killer had at least one accomplice. The bike showed up out of the blue when the killer needed it, and it disappeared when he was done with it. The killer seemed to know BT would arrive at the Hilton early and he was in place. That could have been just good planning, but it could also have been someone reporting because the photo of the killer on his cellphone was prior to the killing. Who was he talking to?
Number 3 is also a possibility because BT was involved in a civil suit along with other high-rollers concerning insider trading. If BT had information that could incriminate someone else, he might have been a target. And if that were the case, all those little messages would be a handy distraction from the real reason.
Right now, I'm leaning toward Number 2, but that could change.
MOO