He’s buried in Michigan, likely no more than 100 miles from where he disappeared. There’s no point in taking the risk of transporting a body hundreds of miles when there are plenty of places to get rid of it right here.
He could be at the bottom of one of the great lakes or any of the hundreds of smaller lakes in Michigan. Buried in a swamp, in the woods, or under a farm.
I heard rumor that he was dropped into molten steel and became a car bumper.
There were lots of rendering plants in Detroit when Jimmy was whacked. I know because I practiced law there at the time and represented one. Never was I so impressed as when they described how they’d take a whole animal’s carcass and reduce it to nothing but mush and cracklings that would then go into dog food. Hard to find an easier, more complete way to dispose of a body, especially if just one of those plants was under the influence of a Mafia associate.