All the stories I've seen refer to a suicide note, the contents of which are not reported. It would be interesting (and confirmation, of sorts, maybe) to know what was in it.
Meanwhile, suspicious minds like mine still think "How convenient." If he felt that guilty, he could have better expiated his guilt by spilling his guts to Congress, rather than blowing his brains out. And with $30+ million in the bank and a family, he had *something* to live for.