"A shallow hole was already dug in the barn floor. He put up a fight, but he was easily overpowered. …(One of the men) picked up a shovel and cracked Hoffa over the head with it. …They threw him into the hole, and buried him alive. He wasn't shot, he wasn't stabbed, nothing like that. A cement slab of some sort was placed on top of the dirt to make certain he was not going to be discovered. And that was it. End of story."
UPDATE: Under that slab, no Hoffa found.