The “murder castle” was a three story building with a basement.

There were over 60 rooms in the house and 51 doors that were oddly places in walls, ceilings, and floors.

Holmes acted as his own designer and architect for the castle and he personally supervised the construction. To avoid suspicion about the odd building style, all of the construction crews were quickly hired and fired, without pay.

In addition to the odd design, the house was also made with with trap doors, hidden staircases, secret passages, rooms without windows, chutes that led into the basement and a staircase that opened out over a steep drop to the alley behind the house.

The first floor of the building housed rented stores and shops, giving the building a normal exterior look. The upper floors were converted into a hotel with spacious living quarters. Holmes had an office on the second floor, but most of the rooms were to be used for “guests.”

When the hotel was examined, they found that many rooms featured different torture techniques like:

• Asphyxiation chambers- where his victims were suffocated with gas.
• Iron plates- prevented the guests from being able to demolish their way out from the rooms of the hotel and kept noise at a minimum.
• Blowtorch- Gas driven fire blowtorches were fixed into the walls in order to burn and torture the victim to death.
• Dissecting table- Used to slowly remove body parts while the victim was still alive or dead.
• Crematory- Used to burn and char bodies while alive or dead.
• Acid vats and quicklime pits- Bodies could be conveniently disposed of by dissolving the flesh into acid.
• Alarms- The rooms all had alarms that buzzed in Holmes’ office if a victim attempted to escape.