1. Aileen Wuornos 

While Aileen Wuornos was working as a prostitute in Florida between 1989 and 1990, she killed seven men by shooting them at point-blank range. When some of the victims’ belongings turned up at a pawn shop, authorities matched fingerprints to Wuornos who already had a criminal record in Florida.

She confessed to the murders but claimed all seven men had raped or tried to rape her and she’d acted in self defense. She was still convicted, sentenced to death and executed by lethal injection on October 9, 2002.

Wuornos scored a 32/40 on the Psychopathy Checklist (anything above 25 is consistent with a diagnosis of psychopathy) but she denied being anything but completely sane. She even dismissed her legal counsel and all pending appeals, writing, “I’m competent, sane, and I’m trying to tell the truth. I’m one who seriously hates human life and would kill again.” But she also told filmmaker Nick Broomfield (who made the documentary Aileen Wuornos: The Life and Death of a Serial Killer) that the murders were, in fact, in self defense but she hated being in prison and just wanted to die.

Wuornos’ last meal was just a cup of coffee and her last words were, “Yes, I would just like to say I’m sailing with the rock, and I’ll be back, like Independence Day, with Jesus. June 6, like the movie. Big mother ship and all, I’ll be back, I’ll be back.”

2. Elizabeth Bathory

The Guinness Book of World Records lists Hungarian noblewoman Elizabeth Bathory as the most prolific female serial killer having been suspected of killing hundreds of young women between 1585 and 1609. She was imprisoned in 1609 but never faced trial thanks to her family’s influence. Instead, she spent five years in solitary confinement until her death in 1614. The official victim count is 80 but she’s suspected to be responsible for over 600 deaths.

Rumors of Bathory’s crimes had been spreading for years before the Hungarian authorities started looking into them. She was accused of abducting peasant girls aged 10 to 14 and severely beating, burning, mutilating, torturing and starving them to death. She was also suspected of cannibalism. If that isn’t bad enough, there are stories connecting her to Transylvania and vampire lore because she was said to have bathed in the blood of virgins to keep herself looking young.

3. Belle Gunness

Belle Gunness, a Norwegian-American woman who stood six feet tall and weighed in at over 200 pounds definitely killed most of her boyfriends and two of her daughters, Myrtle and Lucy. But she also might have killed both her husbands and the rest of her children as well. Her motive was to collect money through life insurance and other valuables and to eliminate potential witnesses. Her main method of killing was poisoning and she managed to get away with it multiple times despite suspicion.

In 1907, after the deaths of two husbands in a row, Gunness put a personal ad in the paper that read: “Personal — comely widow who owns a large farm in one of the finest districts in La Porte County, Indiana, desires to make the acquaintance of a gentleman equally well provided, with view of joining fortunes. No replies by letter considered unless sender is willing to follow answer with personal visit. Triflers need not apply.” A string of middle aged men responded to the ad only to meet Gunness and then never be seen again. In 1908, a fire broke out at Gunness’ farm house. A headless corpse was found in the basement but could never be positively identified as Gunness. Her ultimate fate is still unknown.

4. Jane Toppan

Jane Toppan, or “Jolly Jane” was a nurse in the early 1900s who confessed to killing 31 people. She herself said her ambition was “to have killed more people—helpless people—than any other man or woman who ever lived.” She is a textbook example of the “angel of death” type of killer who takes on a caretaker role targeting sick and vulnerable people. Using her main method, poisoning, she also murdered her landlord and his wife, her foster sister and an entire family of four within weeks of moving in with them. She was finally arrested in 1901 but was found not guilty by reason of insanity and committed to an asylum for life.

Toppan claimed she got a sexual thrill from patients being near death, coming back to life and then dying again which is why she started experimenting with different dosages of drugs like morphine and atropine while she worked as a nurse. Popular podcasts Lore, Criminal and My Favorite Murder all have episodes dedicated to Toppan and the details of her crimes.

5. Nannie Doss

Nannie Doss, aka the Giggling Granny or the Lonely Hearts Killers, was responsible for the deaths of 11 people from the 1920s to 1954 when she confessed after the death of her fifth husband. In total, she had killed four husbands, two children, both her sisters, her mother, a grandson, and a mother-in-law. Her M.O ranged from suffocation to poisoning and the majority of the time she did it to collect on a life insurance policy.

Growing up, Doss was forced to spend more time working on the family farm than going to school and she also suffered a traumatic brain injury at the age of 7 (which she later blamed for her murderous impulses). Doss was referred to as the Lonely Hearts Killer because she loved romance novels and met a lot of her husbands (aka her future victims) through the lonely hearts column in her local newspaper. She also claimed her motive for killing was she just wanted to find the perfect husband. She earned the nickname the Giggling Granny because of her upbeat demeanor. Doss plead guilty to her fifth husband’s murder and was sentenced to life in prison where she died of leukemia at the age of 59.