9 Female Serial Killers Whose Horrifying Stories Are The Thing Of Nightmares

Although women accounted for only 11% of all (known) serial murder cases in the last century, thus making it a semi-rare occurrence, their crimes are still incredibly dark, horrifying, and gruesome.

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So when we asked the BuzzFeed Community to tell us about a female serial killer whose story is so deeply disturbing that we should know about it, they responded with some truly eye-opening cases. Check it out:

Note: A reminder that this post is about SERIAL KILLERS, so please be aware there is disturbing content ahead.

1.Marybeth Tinning, whose nine children died suspiciously under her care.

"I’m amazed more people haven’t heard of Marybeth Tinning. She murdered her children over 14 years in the 1970s and was eventually diagnosed with Munchausen Syndrome by proxy*. It’s absolutely crazy everyone was willing to believe the children all died of an undiagnosed genetic condition and no one got suspicious until her adopted son (who was of no blood relation) also died." —sarahnhazel

*If you're unfamiliar with the term, according to University of Michigan Health, "Munchausen syndrome by proxy (MSBP) is a mental health problem in which a caregiver makes up or causes an illness or injury in a person under his or her care, such as a child, an elderly adult, or a person who has a disability."

Initially, the highly suspicious deaths of Tinning's children had been attributed (by both Marybeth as well as authorities) to things like acute meningitis, seizures, cardiac arrest, sudden infant death syndrome, acute pulmonary edema, and bronchial pneumonia.

However, it was the death of Marybeth's ninth (and last) child, 4-month-old daughter Tami Lynne, where charges were finally brought against her.

Interestingly, Tinning was only convicted of second-degree murder of Tami Lynne. She was tried and convicted in 1987 and sentenced to prison for 20 years to life. She was eventually released on parole in 2018.

2.Frances Knorr, who was known as the "Baby Farming Murderess."

"Knorr was a baby farmer* in Victoria, Australia. There were many bodies found in the backyard of Frances Knorr's house in Brunswick, some which were obviously murdered, and some who probably died of neglect." —extralatte5

*If you're unfamiliar with the term, according to Encyclopedia.com, "Baby farming referred to a system (in the latter half of the 19th century) in which infants were sent away to be nursed and boarded by private individuals for either a flat, one-time fee or a weekly or monthly charge. Baby farmers, usually middle-aged women, solicited these infants through 'adoption' advertisements in newspapers, and through nurses, midwives, and the keepers of lying-in houses (private houses where poor, unwed women could pay to give birth and arrange for the transfer of their infants to baby farmers)."

Born in England, Frances immigrated to Australia and married a man named Rudolph Knorr. Rudolph was sent to prison in 1892 for petty crimes, and Frances was left "pregnant and penniless."

Frances eventually turned to baby farming to make ends meet, but she came under suspicion when the remains of children were found at a residence she previously lived at.

Frances was convicted on Dec. 1, 1893 of "the wilful murder of a female child" and executed by hanging on Jan. 15, 1894.

3.Kristen Gilbert, a former nurse who was convicted of four murders and two attempted murders of patients.

"Just read up on Kristen Gilbert and didn't realize she went to high school a town over from me and went to the same college both me and my sister did (not at the same time, but still...). Interesting and sad story." —michaelababineau14

A Massachusetts native, Gilbert worked as a nurse at the Veterans Affairs Medical Center in Northampton, Massachusetts, in the late 1980s through the mid-1990s.

She was reportedly well liked by her coworkers; however, because so many patients died during her shifts, they also jokingly referred to her as "The Angel of Death."

After a long investigation and trial, Gilbert was eventually convicted of first-degree murder of three veterans, second-degree murder of a fourth, and attempted murder of two more.

4.Amelia Dyer, who was believed to have murdered hundreds of babies in Victorian-era England.

"Amelia Dyer was possibly one of the UK’s most prolific serial killers ever (although it was the 19th century, so never actually proven). She killed a large number of babies." —lampoil

Born in 1837, Dyer grew up in the Bristol area of England. She trained to be a nurse and eventually worked as a baby farmer after becoming a widow and single parent.

Although there is no actual known number of how many children she killed, given the number left in her care and how long she was active as a baby farmer, the estimate by experts has been in the hundreds.

However, it was the discovery of a body, of a baby girl named Helen Fry, inside a package in the Thames River that led investigators back to Dyer, where they found evidence that tied her to other murders of babies left in her care.

Dyer eventually stood trial and confessed to her crimes.

5.Stacey Castor, who killed her husband, attempted to kill her daughter, and was suspected of killing her first husband, too.

"She was convicted of killing her then-husband with antifreeze in 2005. She was also a suspect in the death of her first husband in 2000. In 2007, she tried to kill her daughter by poisoning her with crushed pills, vodka, and orange juice. She also left a suicide note supposedly written by her daughter stating that she killed her father and stepfather!" —nayy

Stacey married her first husband, Michael Wallace in 1990. They had two daughters, Ashley and Bree. Wallace began to feel ill in late 1999, and eventually died in 2000. At the time, doctors reported that he died from a heart attack. Some years later, in 2003, Stacey married David Castor.

A couple of years later, Stacey called police one day, saying David had locked himself in their bedroom. Police arrived to find David dead with a glass containing what was later identified as antifreeze.

Investigators told Ashley, Stacey's older daughter, what had happened. She went to see her mother, who convinced her the two should commiserate together over drinks.

On Feb. 5, 2009, Stacey was convicted of second-degree murder in the poisoning death of David, attempted murder of her daughter Ashley, and forging David's will.

6.Dorothea Puente, who ran a boarding house and killed various elderly people and people with mental disabilities.

"She was active from 1982 to 1988 in Sacramento, California. Poisoned her boarders and buried them in her backyard and still collected their Social Security checks. Nine bodies were found, but there were believed to be 15 total. She was in her 60s when she did this." —majorh

After a tumultuous childhood, several run-ins with the law, and three marriages that came to an end, Dorothea started running a boarding house in Sacramento, California, in 1982.

Over several years, Dorothea took on various elderly boarders or drug-addicted tenants who either died in her care or mysteriously disappeared.

After a tenant named Alberto Montoya was reported missing by his social worker, police also noticed "disturbed soil" on Dorothea's property and soon uncovered the bodies of seven different people.

7.Linda Hazzard, who was known by the nickname the "Starvation Doctor."

"Linda Hazzard operated at a time when 'fad diets' were starting to take off in the early 1900s, along with the concept of wellness and health as beauty. What she did was look for wealthy people (mostly women) who were concerned about their physical health and appearance. Linda would convince them to let her 'treat' them for some made-up disease, and took them away to an isolated cabin."

"She would starve her patients and physically beat them, as well as isolate them from their friends and family so that nobody would look for them when they eventually starved to death. She would dispose of the bodies and claim that the victim had died of whatever made-up 'disease' she was supposedly treating them for…but not before manipulating her victim to leave everything in their will to Linda. Eventually, she was caught by the friends of her two final victims, two sisters who were wealthy British socialites. She starved one sister to death and kept the other imprisoned. She was found out by the police and convicted of manslaughter. Linda later died because of her own diet, starving herself to death in 1938."

—jconway

Hazzard had no medical degree, but due to a loophole for practicing alternative medicine, was actually licensed to practice medicine in Washington state.

Hazzard created a sanitarium called Wilderness Heights in Olalla, Washington, where she "treated" patients via fasting, giving them only small amounts of juices. Her treatments were reportedly responsibly for at least 15 deaths.

Hazzard was sentenced to 2 to 20 years in prison, which she served at the Washington State Penitentiary in Walla Walla.

8.Elizabeth Báthory, who was a Hungarian noblewoman and reported serial killer.

"She was a Hungarian noblewoman who, between about 1590 and 1610, killed hundreds of servant girls. Some say that she bathed in the blood of virgins to keep her looking youthful, although this has been disputed by some historians. She was still incredibly cruel and enjoyed torturing her victims." —kayblu02

Because it happened so long ago, there's not a lot of conclusive evidence surrounding Báthory's practices and what her motivations were.

However, in the early 1600s, after her husband's death, rumors about her cruelty started.

Báthory's servants were put on trial in 1611, and three were eventually executed. Báthory herself was never tried.

9.And finally, Beverley Allitt, who killed four children, attempted to murder three more and caused grievous bodily harm to six others.

"Beverley Allitt used her position as a nurse to kill babies. It’s disturbing mostly because she is eligible for release next year…" —pritchette

Allitt grew up in a small village called Corby Glen in England and, from an early age, exhibited signs of Munchausen's Syndrome.

Allitt carried out her crimes at Grantham and Kesteven Hospital in Lincolnshire while she was a nurse there from 1991 to 1993.

Allitt was given 13 life sentences in 1993 for the 4 murders, 3 attempted murders, and cases of causing grievous bodily harm.

Note: Some submissions have been edited for length and/or clarity.