I wasn't looking for an apples-to-apples "The Beatles fired this dude, and then he also killed himself!" example. The reason why I asked the question is because, if they didn't know that he was mentally ill before they fired him (just because he was diagnosed as a kid doesn't mean that the band knew), then I don't think that they deserve any criticism for not getting the guy any help, much less for the guy killing himself, after they fired him.
And, incidentally, Pete Best was apparently the one I was thinking of.