A nurse named Niels Högel is one of the most prolific medical serial killers of all time (85 confirmed, more than 300 suspected). He administered lethal doses of heart meds to patients so he could try to revive them in front of colleagues for attention and praise.
The Marc Dutroux case, in which a Belgian serial killer and child molester was convicted of having kidnapped, tortured, and sexually abused six girls from 1995 to 1996, is so infamous that more than a third of Belgians with the surname "Dutroux" applied to have their name changed.
23Pedro Rodrigues Filho
A Brazilian serial killer named Pedro Rodrigues Filho killed about 100 people and was jailed for more than 30 years. Because of Brazilian laws, he is currently free and is a popular YouTuber.
A serial killer named Baba Anujka from Serbia is believed to have killed as many as 150 people using poison during the 19th and 20th centuries. She was apprehended in 1928 at the age of 90 and sentenced to 15 years in prison in 1929 as an accomplice in two murders. She was released due to old age after spending eight years in prison.
A cannibalistic serial killer named Dorángel Vargas from Venezuela while serving his prison sentence in 2016 murdered three inmates and then served their remains to other inmates.
26Juan Severino Mallari
There was a serial killer priest named Juan Severino Mallari in the Philippines who killed 57 people to free his mother from being "bewitched."
27Gilles de Rais
A 15th-century knight named Gilles de Rais upon retirement from military service became a serial killer of children. The trial was well-documented, including information on how/why he killed them. Estimates place the number of victims between 80-200. He was hung for his crimes in 1440 A.D. at the age of 35.
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28John Edward Robinson
A serial killer named John Edward Robinson gave away the infant daughter of one of his victims, Lisa Stasi, to his brother and sister-in-law in 1985, for only $5,500 in “legal fees”. They were unable to have children and couldn't adopt through legal means.
Samuel Little was the most prolific American serial killer. He claimed to have killed as many as 93 women and the FBI has confirmed his involvement in at least 50 murders, the largest number of proven cases for any serial killer in US history.
30Paul Michael Stephani
Serial killer Paul Michael Stephani earned the nickname “weepy-voiced-killer”. After committing a murder, he would call the police and tearily confess to his crimes. He even said he would turn himself in, but never did. He was caught after one of his victims managed to fight him off.