Harold Shipman

This British doctor, aka Dr. Death, is respoensible for the death of over 218 of his patients! His reign of terror went undetected from 1975 to 1998. This GP would give his elderly patients large, lethal doses of diamorphene, and would then falsify medical records, attributing their deaths to "old age." 

A local funeral parlour owner noticed a disturbing trend where many of Shipman's patients were dying of the same cause. Authorities soon got wind of it, and an investigation led to Shipman's arrest. He was given life imprisonment, and he hanged himself in his cell in 2004.

-Picture courtesy Reuters-