Another source backs this up, and seems to have interviewed the man's attorney in the past. [0][1]
It's tempting to dismiss foul play on the basis that it's too brazen in the middle of a deposition. However, that's also the height of plausible deniability because cross examinations can get personal and thus emotional.
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I can't help but be reminded of a film quote:
"But that's the way it works with corporate murder. Boss gets wind of something, calls in his head of security, who talks to someone, who talks to a friend of someone. Finishes up with an answering machine in a rented office, a couple of sensitive gentlemen in a blue pickup truck. They will never know who ordered the hit." [2]
[0] https://www.corporatecrimereporter.com/news/200/boeing-whist...
[1] https://www.corporatecrimereporter.com/news/200/brian-knowle...
[2] https://www.scripts.com/script/the_constant_gardener_702/17