it was never proved to be oswald but anyone who has ever read up on the subject would have no doubt that he did it. from a young man he was involved in shady dealings. he was a runner for the mob, he was arrested in russia for spying, and he was an open communist.
the only debate here is who put him up to it as kennedy was not as popular as they would have you believe. my theory is that it was mob related as ruby also had heavy mob connections.
there is no conspiracy or magic bullet im afraid.