I second this. It's a really informative thread.
Regarding the death of the whistle-blower John Barnett. At the time of his death he wasn't actually bringing any new claims of negligence against Boeing, I believe. Rather, the litigation had been altered to argue against his treatment as a whistle-blower.
All his claims he had talked about through various mediums in previous years. They had been investigated (how thoroughly or truthfully is another matter) and at least 1 was upheld.
So at this point I don't really see what Boeing had to gain by killing him. Even if he'd won, I don't believe the payout would be a big deal for Boeing. If anything, his death attracts yet more attention.
Added to this, his family state he was suffering from PTSD and anxiety attacks as a result of his treatment by Boeing and they believe this led to his death.
Yes, there was the self-identified 'friend' who claims Barnett stated that if he died it wouldn't be suicide but who knows if this friend was genuine or if he did make this statement, when it was made.
I'm not completely adverse to the idea of massive corporations carrying out terrible acts to further their interests but in this case I don't really see what Boeing would have to gain by killing a man (in a public space in the daytime?) who'd already very publicly whistle-blown about their manufacturing processes.