The burial at sea was within 24 hours of his death, I believe in accordance to his religious customs. That's the official story according to wikipedia anyway.
Sounds very fishy though. Suddenly a "respect to his religious customs" -- and without anyone seeing the body.
Not saying that it wasn't him -- but could have been torture of what have you involved which they didn't want shown. Or they didn't want him to have a public trial.
I think the idea, officially, was more in lines of "we're going to pay lip service to his religious customs because we don't want to inflame moderates who care about that sort of thing", but yeah. It makes sense to me that they would do it that way, but it certainly leaves open the possibility that everything was not on the level (which I consider plausible, but not not necessarily probable).