I wish I knew if that were true. Our world is complex and it's unclear how to calculate the odds of someone in his position killing himself, accidentally falling off a cliff, or being murdered.
Maybe someone assassinated him, maybe he had a heart attack. There are plenty of plausible scenarios.
Exciting? If anything this is depressing. How people throw around the word "conspiracy" in an attempt to sound smart and disregard(or even dissuade to consider) the most plausible explanation.
Bias? Whistleblower of a mafia goes missing and your first thought is that he commited suicide? Please, you lack intellectual honesty.
Maybe someone assassinated him, maybe he had a heart attack. There are plenty of plausible scenarios.