The F.B.I. estimates that there are anywhere between 25 and 50 serial killers operating in the US at any given time. Because of high profile cases like those of Ted Bundy and Jeffrey Dahmer, serial killers are often thought to be a particularly modern American phenomenon. History, however, shows that they have been around for centuries and have existed in many other parts of the world. (Unfortunately, homicidal psychopaths sometimes wind up in positions of power. These are the most ruthless rulers in history.)

24/7 Tempo compiled a list of the most brutal criminals in history – the vast majority of them serial killers – by consulting sources including Britannica, Biography, Crime Museum, Mysteries Unsolved, Serial Killers, and Capital Punishment in Context. Our list is based on the frequency and depravity of the murders committed by these criminals and the impact their crimes had on their community and their country.

From Indonesia to Denmark, Russia to Colombia, the most brutal criminals in history have lived in all corners of the world. The majority of those on our list, however, hail from the U.S. The press nicknamed many of these infamous murderers with monikers like the Killer Clown, the Night Stalker, and the Casanova Killer. While some preyed on young children, others targeted women, gay men, or the elderly. 

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Some of the most criminals on the list from earlier times were European or American aristocratic women who tortured their serfs or slaves and got away with it largely due to their social status. Other historic killers – also women – made money by pretending to serve as adoption agents for the children of unwed mothers, only to kill the children and keep the adoption fee. These women were some of the most brutal female criminals in history.