Something just isn't hitting me right on this. The man remains "innocent until proven guilty" so what court could prove him guilty and convict him. How do you convict a dead man?
You can't. A dead person can't generally be libeled either (it's only a civil cause of action for living people who have been damaged by the libel). So anyone can say anything about him. Could be he also planted the bomb at the Atlanta Olympics, who knows (/sarc).
The death leaves a lot of open questions.