In the criminal world, a serial killer is typically seen as someone who murders at least three people over more than a month, with some ‘cooling-off’ time between each crime.
Historically, research has shown that the majority of serial killers are men – for example, ONS statistics over two years from the end of 2022 to year-end 2024 revealed that 92% of suspects convicted of homicide in England and Wales were male. So, it stands to reason that much of what we see and hear of serial killers – in the news, documentaries, and fictional drama series – centres around male perpetrators.
However, in recent years, there’s been growing interest in the minority of female serial killers; with shows like Killer Women with Piers Morgan proving hugely popular, and making many of us more curious about what drives women to kill.
But what are the different motives of male and female serial killers? And who are some of the UK’s most notorious female serial killers in recent history?
Trigger warning: This article is for informative purposes only and is not intended to glorify tragic events or make light of them. Although true crime cases can provide helpful insight into the human psyche and criminal legal system, we also appreciate that exposure to topics relating to violence and death can be distressing for some people. Therefore, reader discretion is advised.
Our thoughts go out to the victims, families, and anyone else affected by these – or similar – events.
How do male and female serial killers differ?
According to 2019 research, male serial killers tend to “hunt” their victims, who are often unknown to them – while female serial killers tend to “gather” victims, often killing people that they already know.
Associate professor of psychology, Marissa Harrison, from Penn State University, suggested that ancient human roles may help explain these differences.
“Historically, men hunted animals as prey and women gathered nearby resources, like grains and plants, for food,” Harrison said. “As an evolutionary psychologist, I wondered if something left over from these old roles could be affecting how male and female serial killers choose their victims.”
Through research for Harrison’s book, Just As Deadly: The Psychology of Female Serial Killers, she also found that 39% of female mass killers work in healthcare professions and are likely to be well educated.
Other research has also found that men and women serial killers may have different motives. For example, male serial killers are often driven by sexual compulsion, while women may be more likely to kill for money, revenge, attention, or specific gain. Women have been shown to use more low-key methods, too, such as poisoning, drowning, and suffocating; while men typically take a more varied approach.
Plus, when looking at the behaviour leading up to the killings, studies have shown that male serial killers are more likely to stalk their victims (65.4% compared with 3.6% for females).
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7 of the UK’s most prolific female serial killers
Understanding the differences between male and female serial killers can be useful when considering the profiles of some of the most prolific female serial killers in history.
Let’s take a closer look at some of these below…
1. Mary Ann Cotton
Mary Ann Cotton – also known as the Dark Angel – was born in 1832 and holds the grim title of Britain’s first female serial killer. Operating in the mid-19th century in North East England, she’s suspected of poisoning up to 21 people, including 11 of her 13 children and three husbands. Driven by greed and life insurance payouts, she used arsenic concealed in tea to silently eliminate family members.
Her role as a mother, nurse, and housekeeper initially kept her out of the spotlight. But, eventually, the recurring deaths around her raised suspicion, so she was arrested and her case brought to trial. After Cotton was found guilty, unsurprisingly, public outrage ran high, and she was hanged at Durham jail in 1873.
Cotton’s case shattered Victorian perceptions of women being the “gentle sex” and highlighted the dangers of readily available arsenic. It also sparked debates about mental health, motive, and the complexities of evil.
2. Amelia Dyer
British nurse Amelia Dyer took the lives of hundreds of infants in her care during the 19th century. She offered to adopt unwanted babies for a fee, but instead strangled, starved, or drugged them. It’s estimated that she killed up to 400 babies, making her one of Britain’s most prolific murderers.
But Dyer’s facade crumbled in 1896 when evidence of neglect and a baby’s body were found at her Reading home. A trial exposed her systematic killings, which were motivated by greed and a chilling indifference to life. Despite public outrage, Dyer’s age (58) and claims of insanity swayed the jury, resulting in a lesser sentence. However, public pressure led to a retrial, and she was hanged that same year.
Dyer’s case exposed the plight of vulnerable children and sparked reforms in childcare and adoption practices. And her story remains a haunting reminder of the darkness that can lurk behind supposed goodwill.
3. Beverley Allitt
In 1991, nurse Beverley Allitt – sometimes referred to as the Angel of Death – went on a killing spree. She poisoned 13 children, killing four of them. Allit overdosed her victims on potassium and insulin or injected an air bubble into their bloodstream to collapse their lungs.
Allitt’s suspicious behaviour raised red flags. There were too many infant deaths, unusual symptoms, and insulin injections without a clear need. The other nurses noticed patterns and reported their concerns, and investigations revealed inconsistencies in her actions and medical records, leading to her capture. It’s believed that Allitt suffered from Munchausen syndrome by proxy, causing her to harm and kill others for attention.
Allit was apprehended in 1992 and charged with murder and attempted murder. She was found guilty of all charges in 1993 and received 13 life sentences, which she is currently serving at Rampton Secure Hospital.
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4. Myra Hindley
Myra Hindley, born in 1942, remains notorious for her involvement in the ‘Moors Murders’ alongside her boyfriend, Ian Brady. Between 1963 and 1965, the couple lured and murdered five children in and around Manchester, committing unimaginable acts of cruelty.
Both were jailed for life in 1966 after Hindley’s 17-year-old brother-in-law witnessed Brady killing another 17-year-old with an axe – and went to the police with his story, after worrying that he would meet a similar fate. Hindley appealed against her sentence several times, claiming that she’d been rehabilitated. But she was never released and died in prison in 2002, aged 60.
While initial coverage of the case focused solely on Hindley’s monstrous deeds, later discussions explored a more complex picture. Some argue that Brady manipulated Hindley, while others theorise that she was seeking attention and her remorse was insincere.
Regardless of interpretations, Hindley’s actions left an indelible mark. They highlighted the chilling depths of human depravity and sparked debates on evil, rehabilitation, and societal responses to unforgivable crimes.
5. Rose West
Rose West was a convicted English serial killer who, along with her husband Fred West, tortured and murdered at least 12 young women and girls between 1967 and 1987. This includes their daughter Heather and Rose’s stepdaughter, Charmaine.
The couple lived in Gloucester, in a home that later became known as the ‘House of Horrors’. It was the burial site of many of the victims, and DNA evidence played a crucial role in identifying the victims and linking them to the Wests.
Psychologists have since tried to understand what could have turned Rose West from a shy teenager into a sadistic serial killer. Some hypothesise that it was her exposure to shock therapy while in her mother’s womb, coupled with being sexually abused by her father.
During her trial, Rose blamed Fred for the murders, claiming that he bullied her and forced her into things. Fred had a history of being sexually abused, too, and many believe that the pair bonded over their violent pasts and insatiable desire for sex.
Rose West was convicted of 10 murders in November 1995 and is currently serving a life sentence at HMP New Hall in West Yorkshire – though she’s still never made a full confession and has since changed her name to Jennifer Jones. Fred West hanged himself in prison in January 1995, before his trial could begin.
6. Lucy Letby
The most recent crimes committed among these female serial killers are by Lucy Letby, a former UK neonatal nurse. She murdered seven babies and attempted to murder seven others between 2015 and 2016 – but she wasn’t arrested until 2018 after a disturbing pattern emerged at the Countess of Chester Hospital, where she worked.
Following an alarming spike in unexpected, unexplained deaths of babies in the neonatal unit, the police requested the analysis of tens of thousands of medical files by a neonatologist, who concluded that the deaths weren’t the result of natural causes. And, later, a pathologist ruled that they were caused by inflicted harm. Some babies were given too much milk or injected with air or insulin, while others had their breathing apparatus tampered with.
In the months that followed, investigators spent hours analysing the shift patterns and rotas of staff in the neonatal unit. Lucy Letby was always on shift – often alone – with the babies before they collapsed.
After a lengthy trial, Letby was sentenced to a total of 15 life sentences for her crimes – the final of which was handed to her in 2024 during a retrial for the attempted murder of Baby K in 2016. The CPS confirmed that Letby will never be released from prison.
7. Joanna Dennehy
In 2013, Joanna Dennehy stabbed and killed three men and attempted to murder two more in a 10-day spree in Peterborough. The first three men were people she knew – one a housemate, another a love interest, and the other her landlord, while the next two were encountered randomly while out walking their dogs.
After killing her third victim, Dennehy phoned a friend and sang the Britney Spears track “Oops I Did It Again” down the line. She committed the crimes alongside her accomplice, Gary Stretch, and bragged to friends while on the run that the pair were like the modern-day Bonnie and Clyde. Dennehy’s reasoning for the killings was that she found it “moreish and fun” – and she was strongly against the idea of killing women, especially those who had children.
Following the disturbing crimes, Dennehy went on the run but was captured within days. She was jailed for life and sent to maximum security prison, HMP Bronzefield. Here, she threatened to kill fellow inmate Rose West in a bid for increased status and attempted to plot her escape. One alleged plan involved cutting off a prison guard’s fingers to allow her to open biometric doors.
Dennehy’s actions in prison led to her being kept in solitary confinement – something which she attempted to seek compensation for in 2016, over it being a violation of her human rights. Dennehy was also believed to have started a relationship with a prison guard after explicit letters were found during a search of his home, so she was transferred to HMP Low Newton, 300 miles away.
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Final thoughts…
Female serial killers are rare, but not as rare as commonly thought.
Learning about female serial killers can help us understand the causes and consequences of female violence, which is often overlooked or misunderstood by society. It can also help us to recognise the diversity and complexity of human behaviour, and challenge the stereotypes and assumptions that may hinder the investigation and prosecution of female perpetrators.
For more true crime content, why not check out our article: 5 chilling cold cases solved by DNA evidence?