Built a one hundred-room mansion complete with gas chambers, trap doors, acid vats, lime pits, fake walls and secret entrances. During the 1893 World's Fair he rented rooms to visitors. He then killed most of his lodgers and continued his insurance fraud scheme.

He also lured women to his "torture castle" with the promise of marriage. Instead, he would force them to sign over their savings, then throw them down an elevator shaft and gas them to death. In the basement of the castle he dismembered and skinned his prey and experimented with their corpses.

He killed over 200 people.

Dax.-