Also understand that it is pretty rare for a whistleblower to have any future in the industry they are blowing the whistle on. That is throwing away years of schooling and often decades of experience. People tend to not do that if they aren't already ill and not expecting a long life.
As for "if I die, it is not suicide": Gonna get real dark for a moment. A lot of people are just looking for a way to make their life, or death, matter. Someone realizing they don't want to put themselves and their family through a very long trial might very well use that as an excuse to take the easy way out.
All that said: Obviously these need to be investigated. But there is a big difference between investigating a suspicious death and immediately jumping to conspiracy.