His name was H. H. Holmes and he is also thought to be THE Jack the Ripper because he was in London at the exact same time and was a medical professional. He went to medical school to learn how to kill people. He is fucking scary.

And Supernatural did an episode on him. I first saw it when I was like 10 and it still creeps me out to this day. 

I read a book about him. He had multiple wives at the same time, almost all of whom he killed after separating them from and or killing their children. He was said to be incredibly charming and charismatic, and killed almost all the women he seduced. 

Reminds me of The Collection!