Carl Panzram
This guy was a serial killer, rapist, arsonist and burglar and a human-shaped horror monster.
He was an immensely powerful man who would rob men, then rape them. In his autobiography, he said he did it not because he was gay, but because it humiliated his victims. His spree lasted for 8 years and multiple countries in 1920, until he ended up crashing his yacht and fleeting to Africa.
He was arrested in 1930 and sentenced to be executed when he started doing the same thing to his fellow inmates. They ended up hanging him, with is last words being “I wish the entire human race had one neck, and I had my hands around it!”. Charming.
You forgot Harold Shipman, probably the world's most prolific serial killer and a doctor.