yep
during the night, the floosie woke up to find herself alone and started screaming. There was then the noise of a toilet flushing and S Creek entered from the adjacent bathroom ha ha ha (this was a clue)
the "bedroom" had a canopy over the bed, that dirt, dead flies and (originally) nasty gunge fell through.
They previous victims who had disappeared, woke up (alive) the next morning, found themselves dirty or covered with spiders and flies, went into the adjacent bathroom, ran a bath and got in.
The bath was on a pivot, and after they had got in, it hinged down so they fell into a large water tank below and drowned.
Yesterday's floosie fell into the tank and found an assortment of fresh, recent corpses in there, plus old rotted ones and skeletons.
S Creek and the gardner realised something was wrong and ran up there in time to pull her out before the bath swung back on its mechanism.
For some reason the "haunted" room was not actually at the top of the tower where it looked to be from the outside, the private staircase led to a murder room hidden in the roof but with a false ceiling shaped to look like the top of the tower.
BTW that nasty picture of an old person smoking a pipe was a valuable Old Master. The old lady had, as a young woman, snatched it off the wall in a house she was staying in during a house fire, instead of rescuing the disabled person who was trapped in the same room and presumably killed in the fire. I expect this was to make her guilty. The other conjuror had married his assistant secretly, then murdered her by cutting her throat in his storage warehouse, then swapping her body for a dummy after creek and the buddies had found it but before the police arrived
The other conjuror faked an alibi with his other woman whom he later tried to murder but Creek arrived and saved her. The other magician then killed himself with car exhaust and hosepipe.