1860s to 1896 UK - Only convicted of one murder. Killed 274 babies, confirmed after her death when their bodies were recovered from the River Thames. Estimated to have killed between 274 and 400 babies, however, lack of evidence cannot confirm the exact number. Baby-farm murderess.
1990s Columbia - Child-murderer, torture-killer, and rapist known as 'La Bestia' aka 'The Beast.' Convicted of killing 138 victims but suspected of murdering over 300 victims, mostly street children. Sentenced to 1,853 years but could only be imprisoned for 30 which was reduced to 22 after aiding investigators.
1980s Columbia, Peru, Ecuador - Child-murderer and rapist, convicted of killing 110 young girls but confessed to killing 300, exact total unknown. Known as 'The Monster of the Andes' and sentenced in 1983 but released in 1998, believed to still be killing.
1990s United Kingdom - Convicted of 15 murders and responsible for the deaths of 218 patients identified by inquiry but he is believed to have killed up to 250 people. He would inject diamorphine into his patients and then falsify his own medical records reporting that his patient had been in poor health. Known as Doctor Death.
1500s Hungary - Hungarian noblewoman, countess, allegedly the most prolific female murderer in history. Total killings unknown, accusations pointed to between 100 and 700 victims but she is believed to have actually killed 100 to 200 people. Possibly the victim of conspiracy and may have been innocent.
1800s Russian Empire - Russian noblewoman. Accused of up to 138 murders; found guilty of 38 murders.
1850s India - Thugee cult leader. Confessed to have personally murdered more than 125 victims and present at 931 murders perpetrated by his cult. He is often quoted as having killed 931 people. This figure was the number of murders he had been present at, though he was never convicted of these murders. This lower figure was the conclusion of James Paton's investigations in the 1830s. The Thugee cult as whole, however, were adjudged to have been responsible for 50,000–1,000,000 murders in total.
1940s Japan - Euthanized more than a 103 newborn children. As a maternity nurse she killed infants born to parents unwilling to care for them during the prohibition of abortion in Japan. Sentenced to 4 years in prison.
1996 to 1999 Pakistan - Child-murderer. Pakistan's most profuse killer, confessed to killing 100 children and convicted of the same number. Found dead in his prison cell possibly tortured and murdered, ruled a suicide.
1982 to 2000 United States - The United States' most prolific serial killer; also known as The Green River Killer. He almost exclusively targeted escorts from Seattle. Once there he would proposition a prostitute, drive to the banks of the Green River, and strangle her to death. After murdering his victim he would dump their body in the nearby water. Suspected of killing over 90 victims, confessed to 71, convicted of 48.
Number of Victims
1955 to 1964 Mexico - Two sisters who hired prostitutes and murdered them after they were deemed useless. Probably the work of four of the sisters, sentenced to 40 years in prison. Body count varies due to the combined work of the sisters being impossible to assign to them individually.
80 - 200+
1435 to 1440 Brittany - Child-murderer and companion-of-arms to Joan of Arc. Convicted of 80 murders and suspected of 200, estimated total ranges substantially.
80 - 110
1953 to 1982 United States - Child-murderer, known as the 'Meanest Man In America' and 'Pee-Wee', convicted of killing 9 people but suspected of 80 murders. Killed three victims while incarcerated, one of which by using C-4. Later confessed on death row that he had murdered 110 victims. Executed in 1991.
72 - 150
1974 to 1986 Columbia, Ecuador - Child-murderer, believed to have possibly raped and killed over 150 victims primarily young virgin girls. Confessed to killing 72 victims and incarcerated with Pedro Alonso Lopez. Considered to be intelligent and believed to have been motivated to kill from his stepmother abusing him as a child.
70 - 100
1967 to 2003 Brazil - Convicted and sentenced to 128 years, but the maximum one can serve in Brazil is 30 years. He has claimed to have killed over 100 victims, 40 of them inmates.
2000 to 2003 China - Killed 65 victims in four provinces of China, known as the 'Monster Killer.'
1992 to 2006 Russian Federation - Known as the Chessboard Killer. Killed at least 49 victims and suspected of 61, claimed 63. Russian Federation's most prolific serial killer.
14 - 60
1950 to 1999 United States - Torture-murderer, targeted women, convicted of killing 14 victims and suspected of 60 murders. Constructed a $100,000 torture chamber which he called his toy-box to murder victims in.
1977 to 1985 Italy - Underboss of the Sicilian Mafia during the Second Mafia War convicted of 58 murders; exact total unknown. Murdered and placed on trial after his death, sentenced to life.
1982 South Korea - Largest spree killing in modern history, killing 56 and injuring 35. He committed suicide, bringing the total to 57 dead.