I guess that would depend on whether or not LE is monitoring that address. Was the address publicly available to the dreammarket? If so it's likely being watched. If the address was created just for that payment, like it should have been, then you're probably okay.

You could still get nailed if the owner of the wallet then transfers the payment from the one off address to their holding address or something like that. All of that activity can be traced on the blockchain.

Maybe move your funds from Xapo to something else just in case..