Dennis Nilsen..this guy was nasty
British serial killer who first stored his victims under the floorboards of his flat for months. They not only began to smell, he left some of the bodies so long they had advanced decompostion complete with all of the associated maggots and insects.
Then he moves to a flat where he couldn't hide the bodies under the floorboards. So he chopped them up and flushed them down the toilet
He gets caught because someone noticed a sewer grate outside clogged up with flesh and chunks