Ahem. The base rate for a healthy person dying in the week or so leading up to their important testimony is tiny. It's reasonably likely (20%+) that this was foul play.
Like the report that he killed himself due to pressures of the case or the fact that he gave 32 years of his life to a company that's calling him a traitor isn't compelling enough.
Same, which is why I'm disinclined to believe shadowy cabals ordering assassinations when it's more likely he was just under some of the highest pressure and scrutiny of his life.