The world is unfortunately filled with sick and twisted people who have committed some of the most atrocious acts. Things that most of us could not even imagine in our darkest nightmares — nor do we want too. These people exist, we all know that, but there is something even more sinister about a couple deciding to kill together.

Throughout history, there have been a lot of famous serial killer cases, but the crimes committed by couples appear to be far less common, which makes these people a bit of a mystery. What went so wrong in their past that they had to take the life of another human? How did their love get so twisted that it resulted in countless innocents being hurt? While we know the circumstances surrounding many of these killers, we can never truly know the answers as to why they committed these crimes.

From spree killings to methodical, well-thought-out murders: Some of these couple’s had a master and slave type of relationship, others were simply complicit in their partner’s crimes, and then there are those who actively participated. Below are 15 notorious killer couples whose relationships took a gross twist and resulted in them taking lives, together.

15. Paul Bernardo and Karla Homolka

Paul Bernardo and Karla Homolka were dubbed by the media as “the Ken and Barbie Killers” because of their good looks. But behind their seemingly normal facades, these two were one of history’s most cruel and twisted couples. During their time together the pair killed three women, including Homolka’s younger sister Tammy, who was only aged 15 at the time of her death.

The Canadian couple reportedly met in 1987 at a hotel restaurant in Scarborough when Homolka was aged 17, and Bernardo was aged 23. In 1989 the couple became engaged and were married in 1991 — by this time they had already caused two deaths.

Bernardo was already a serial rapist, but when he met Homolka she encouraged his depraved fantasies of deflowering virgins, despite reportedly being physically and emotionally abused by Bernardo.

Homolka was offered a plea deal by prosecutors and reportedly only received a 12-year sentence for her role. She was released from prison in 2005. While Bernardo received a life sentence with the possibility of parole. He will be eligible for full parole in 2018, although it’s unlikely that he will be released.

14. Bonnie and Clyde

Bonnie and Clyde are probably the most notorious killer couple, and their story has been made into multiple movies. But who was this couple who killed 13 people, before being shot to death by police during an ambush in Louisiana?

Bonnie Parker and Clyde Champion Barrow met in Texas in 1930. At the time she was aged 19 and already married to Roy Thornton, who was serving time behind bars. Barrow, on the other hand, was unmarried and aged 21. Not long after the couple first met, Barrow was jailed for burglary but was paroled in 1932.

The couple then ran away together and started their two-year crime spree (which included robbery and murder) along with their gang. While Clyde would kill anyone who threatened his freedom, according to Biography, they often allowed people to go, unharmed.

13. Suzan and James Carson

Suzan and James Carson, also known as “San Francisco Witch Killers”, were motivated to kill people who they believed to be witches — I know, it sounds like a modern-day Salem witch hunt!

When they first met in 1977, they seemed like a relatively normal couple. Suzan was a divorced mother-of-two, and Carson also found himself single — he reportedly turned violent within the last year of his marriage, which resulted in his wife leaving him. The following year, the couple began traveling through Europe, and according to Ranker, while in England they were married in Stonehenge, under the light of the moon.

Then in 1981 the couple began their killing spree. It is believed that Suzan, who was ten years older than Carson, was the mastermind behind the crimes, which resulted in them killing three people before being arrested after a high-speed chase with the Los Angeles Police Department. It could have been a lot more had they not been stopped, because people on their hit list included Johnny Carson and President Ronald Reagan.

12. David and Catherine Birnie

Australian couple David and Catherine Birnie’s lives were so dark that their story was even turned into a movie called, Hounds of Love.

Catherine reportedly met David through mutual friends when they were adolescents — she was aged 12 and he was 14. They both had a tough childhood: Catherine’s mother was dead, and David’s mother was reportedly an alcoholic, and it seemed the two bonded through their pain. However, they continued to get into trouble with the law, and Catherine was jailed. This time apart helped Catherine to breakaway and marry a man named Donald McLaughlin, who she had six children with.

But at some point, she returned to David, and in 1986 they began their spree. Their crimes lasted for five weeks in 1986, during which they killed four women at their Moorhouse Street home — which is why they were nicknamed “The Moorhouse Murders”. A fifth victim, Kate Moir, was able to escape through a window.

11. Charles Starkweather and Caril Ann Fugate

Charles Starkweather was a James Dean wannabe who was bullied when he was in school; Caril Ann Fugate was a schoolgirl. She was aged 14 when she met Starkweather through their mutual friends. He was five years her senior, but despite this age gap, it’s believed they were madly in love, with Starkweather reportedly even getting a job close to Fugate’s school.

It was the disapproval of Fugate’s mother and her stepfather that would cause their murder spree. Fugate’s parents prevented her from seeing the much older Starkweather, and so the couple murdered them, as well as their 2-year-old daughter, in their home. The couple lived in the house for six days after the murder, and told relatives that the family had the flu. When they realized that family members were getting suspicious they, fled and embarked on a crime spree.

The couple was responsible for the deaths of ten people in 1958.

10. Gwendolyn Graham and Catherine May Wood

Gwendolyn Graham and Catherine May Wood were a lesbian couple who met at a nursing home, where they both worked as nursing aids.

According to reports, the couple killed five elderly people at a nursing home during January and February of 1987. It is believed that Graham committed the first murder by smothering an elderly woman suffering from Alzheimer’s disease; Graham was portrayed by Wood as being the one behind the planning, and the killings.

The strangest thing about these killings is that according to Murderpedia, the couple were trying to enhance their sex life with the murders, and would have sex shortly after. They were arrested a year later when Wood confessed the crimes to her ex-husband. She reportedly claimed that she feared Graham may continue the crimes.

9. Carol M. Bundy and Doug Clark

Carol M. Bundy and Doug Clark were known as “The Sunset Strip Killers” for their crimes, which took place in the area of Los Angeles of the same name.

Bundy had been in a number of abusive relationships before she met Clark at a bar in 1980. She fell for him immediately, and according to reports, he moved into her apartment that same night.

Their crimes were fuelled by their strange sexual desires, which began by having sex with prostitutes and escalated into wanting to have sex with someone while killing her. This is the reason six teenage prostitutes lost their lives. In addition to the prostitutes, Jack Murray was the seventh victim because Bundy (who had a bit of a crush on him) confessed their crimes to him while drunk. She then decided to she needed to get rid of him.

8. Raymond Fernandez and Martha Beck

Martha Beck and Raymond Fernandez became known as the “Lonely Hearts Killers,” and they found their victims the same way that they met, through the lonely hearts section of a newspaper ad. They had intended to seduce and rob women through the ads, with Beck pretending to be Fernandez’ sister or sister-in-law.

But things escalated, and the pair is believed to have killed around 20 people over the period of two years, between 1947 and 1949. As for their relationship with each other? Beck was overweight and unemployed. She seemed insecure and was extremely jealous — she allegedly killed one of the women in a rage.

She had two children, one from a one-night stand, and another from a brief marriage; so when she met Fernandez — who thought of himself as a bit of a ladies man — she fell fast. She even left her children to go and live with Fernandez in New York.

7. Judith and Alvin Neelley

Judith and Alvin Neelley seemed an odd couple right from the beginning. When they first met in 1979, Judith was aged 15, and Alvin was aged 26. He was also married at the time, but got divorced and impregnated Judith shortly after.

From the beginning of their relationship, they enjoyed a life of crime and committed robberies. According to New York Daily News, Judith even gave birth to the couple’s twins while behind bars. But when she and Alvin were reunited after serving time, they devised their sick plan to lure teenagers and sexually assault them.

In 1982 they ended up torturing and killing two women, the first a girl just aged 13 — who Judith shot — and the second a young engaged couple. While the woman died, her fiancé survived the attack and was later able to identify the couple.

6. Alton Coleman and Debra Brown

Debra Brown reportedly had a relatively normal childhood but suffered a severe head trauma which affected her mental abilities. She was reportedly borderline mentally disabled, according to Rolling Stone.

Alton Coleman, however, had already been charged with a number of crimes, including sex crimes, when he met Brown in 1983. Coleman was seven years her senior.

Then, in 1984, he was charged with the rape of a 14-year-old girl, and went on the run, taking Brown with him. This began their 2-month killing spree that resulted in eight murders and seven rapes, as well as abduction and armed robbery.

According to Murderpedia, the two had, what Brown’s attorney’s referred to as, a master/slave relationship, with Coleman appearing to be in the dominant one in the relationship.

5. Daniel and Manuela Ruda

German couple Daniel and Manuela Ruda reportedly met in 2000 after Daniel posted a personal ad in a heavy metal music magazine. It read, “Pitch-black vampire seeks princess of darkness who hates everything and everyone and has bidden farewell to life.”

The couple moved in together shortly after meeting, they slept in a coffin and practiced Satanism. They had an odd appearance and Daniel even filed his teeth to look more like a vampire. In June of 2001 the couple was married, and one month later they reportedly killed Frank Hackert, in their home. Hackert’s death was reportedly part of a ritualistic killing so that they could drink his blood. He was stabbed 66 times.

The pair were convicted in 2002, and while behind bars, Manuela made the decision to divorce Daniel.

4. Jasmine Richardson and Jeremy Steinke

Jasmine Richardson was aged 12 when she started dating the much-older Jeremy Steinke, who was aged 23. Unsurprisingly, her parents were unhappy with the coupling, and told their daughter that she could no longer date Steinke.

While most teenagers’ act of defiance may be for them to sulk for a few days, or at worst try to run away from home, Richardson was clearly not an average teenager because she enlisted the help of her boyfriend to kill her family. On April 26, 2006, the couple killed Richardson’s parents, as well as her 8-year-old brother, Jacob. They were arrested the next day.

Another creepy aspect of this relationship is that Steinke is believed to have liked the taste of blood, he also thought he was a 300-year-old werewolf — although I’m not sure how well werewolves cope behind bars.

3. Gerald and Charlene Gallego

Gerald Gallego wanted to have sex slaves, and his wife, Charlene, was complicit in his wishes.

Gerald had a hard upbringing, his father was reportedly a criminal who was executed, and his mother was a prostitute. He started commiting his own crimes at the age of 13. Charlene, on the other hand, had a very normal childhood by all accounts, but when she was a teenager she became mixed up with drugs and alcohol.

In 1997 the couple met. Charlene had been married twice before meeting Gerald, while he had been married seven times. The Gallegos had a passionate romance, and after one week they had reportedly moved in together. According to reports, their sex life was definitely not vanilla!

Charlene was reportedly sexually submissive, while Gerald was the dominate. Charlene was reportedly bisexual, and the couple enjoyed threesomes; but this escalated after a year, and Gerald revealed his desire to have sex slaves.

In 1978, the couple started their abduction and killing, and by 1980 they had killed ten victims, mostly teenagers.

2. Ian Brady and Myra Hindley

Ian Brady had a very tough upbringing. He was neglected by his mother, and grew up in foster homes. When he was a teenager, he went to live with his mother and his stepdad and started drinking heavily. In comparison, Myra Hindley had a normal childhood.

The couple met at their work; Brady was working as a sales clerk, and Hindley was a secretary. Hindley, who was aged 18 at the time, fell hopelessly in love with Brady and was impressed by his ideologies; he was obsessed with Hitler and Nazi Germany and had read Mein Kampf. According to reports, it took Brady a lot longer to reciprocate Hindley’s affections.

Brady then became fixated on the idea of committing the perfect murder. Between the years of 1963 and 1965, the couple killed five victims, ranging between the ages of 10 and 17. Their crimes were horrific, and became known as “The Moors Murders” because of where they buried the bodies.

1. Mary Frances Creighton and Everett Appelgate

This is definitely one of the strangest killing pairs on the list!

Mary Frances Creighton, her husband, John Creighton, and their daughter, Ruth, moved to Baldwin, New York, where they met a couple, Everett and Ada Appelgate. The families started living together because it was the Great Depression, and money was scarce.

During this time Everett started to seduce the teenage Creighton daughter. According to New York Daily News, he would take her on drives, and the pair were reported to have started a sexual relationship. There is some confusion surrounding the circumstances of the death of Appelgate’s wife, Ada, but in 1936 both Appelgate and Mary Creighton were tried for poisoning her.Both were found guilty and executed by the electric chair.

Their romantic link to each other, if any, and their motives for both wanting Ada dead remain unclear, but because they were convicted together, they deserve a spot on our list. Interestingly, prior to this murder, Mary also stood trial for the death of her brother, Ray Avery (who died of arsenic poisoning), as well as her mother-in-law, but she was acquitted of both charges.