Holmes switched builders and architects frequently throughout the building’s construction, so no one involved was able to realize the gruesome end goal of all the odd parts.
The castle was completed in 1892 and by 1894 police would be exploring its winding passages while Holmes sat behind bars.
At first, they were confused at what they found.
There were hinged walls and false partitions. Some rooms had five doors and others had none. Secret, airless chambers hid underneath floorboards and iron plate-lined walls stifled all sound.
Holmes’ own apartment had a trapdoor in the bathroom, which opened to reveal a staircase, which led to a windowless cubicle. In the cubicle, there was a large chute that tunneled through to the basement. (Spoiler: It wasn’t used for dirty laundry.)
One notable room was lined with gas fixtures. Here, Holmes would seal his victims in, flip a switch in an adjacent room, and wait. Another chute was nearby.
All of the doors and some of the steps were connected to an intricate alarm system. Whenever someone stepped into the hall or headed downstairs, a buzzer sounded in Holmes’ bedroom.
The first clue about the bizarre floor plan’s true purpose came to the cops in a pile of bones.
Most of them were animals, but some of them were human — so small they had to have belonged to a child, no more than six or seven years old.
When they descended into the cellar, the scope of the building’s hidden horrors was revealed.
Beside a blood-covered operating table, they found a woman’s blood-soaked clothes. Another surgical surface was nearby — along with a crematory, an array of medical tools, a bizarre torture device, and shelves of disintegrating acids.
Holmes fascination with dead bodies had lasted long past college — as had his surgical skills.
After dropping his victims down through the chutes, he would dissect them, clean them, and sell the organs or skeletons to medical institutions or on the black market.