[superuser2]

Death that looks like suicide, the feeling that one has made a monumentally important discovery, and the perception that one is being persecuted by secret agents might occur together for several reasons. Having upset the intelligence community is probably one, but so is mental illness, and schizophrenics are a lot more common than Edward Snowden figures.

Further, suicide and automobile accidents are leading causes of death among healthy people. It would be strange if they didn't happen sometimes to people who claimed to be persecuted by shadowy conspiracies, real or imagined.