Sorry to hear about Caesar's passing.
The "in pieces" part makes it sound like something picked him apart during a moult or something. Then again, he had the tank to himself, didn't he? You're probably right...moulting-related issue.
BV
P.S. MissFishy...I've got a relatively new pair of blue crayfish now which I am breeding, so whenever I have some offspring ready (still waiting for the female to berry-up) I'd be more than happy to send you one (or at least a few anyway) for the cost of shipping.