What happens when a husband and wife team up to commit unspeakable acts and cover up each others tracks?
We've detailed the darkest cases of true partners in crime.
Ian Brady and Myra Hindley
Ian Brady and Myra Hindley are best known for being one of Britain's most evil partners in crime, killing five victims between July 1963 and October 1965. Their victims were between the ages of 10 and 17. All of them were tortured, sexually assaulted and were killed and buried on Saddleworth Moor.
The couple had even taped the brutal torture of one of their victims as she died, which was played to the jury during their trial in 1966.
Hindley was dubbed the most evil woman in Britain, for letting the victims suffer. She took an active role in the abduction and torture of the victims, luring them into the car with the story of a missing glove.
Hindley died at the age of 60 from a chest infection after suffering a heart attack in 2002.
Brady continues to serve his sentence at Ashworth Hospital, and still refuses to give any information up about the whereabouts of Keith Bennett's body, who went missing in 1964.
Fred and Rosemary West
Fred and Rose West tortured and raped numerous young women and girls, murdering at least 12, including members of their own family.
Rosemary West is believed to have killed Charmaine (Fred's step-daughter from his first marriage) shortly before Fred was released from prison for theft in June 1971. Charmaine disappeared in June, and Rosemary explained this by claiming Fred's ex-wife had called and taken Charmaine back to Scotland. When Fred's ex-wife did in fact turn up to collect Charmaine in late August, she too disappeared.
Fred and Rose were married in 1972 and in June Rose gave birth to their second daughter, Mae. Around this time, Fred also encouraged Rose to work as a prostitute. Rose eventually bore seven children.
Heather Ann West, the couples 16 year old daughter, became the focus of Fred's attentions after her sister Anne Marie left home at 15.
Heather had complained about the abuse she suffered to her friends, and when news of this got back to Fred and Rose, they decided to kill her.
In June 1967, Fred and Rose killed Heather. Heather's disappearance, Fred and Rose's changing stories about her whereabouts, and the threats to their other children that they would "end up under the patio like Heather" if they misbehaved led to the Wests' arrests in 1994.
Fred and Rose West were brought before a magistrates' court in 1994; he was charged with 11 murders and she with 10. On the 1st January 1995, Fred hanged himself in his cell.
The evidence against Rose was circumstantial, as she never confessed. She was tried in October 1995 and was found guilty of all 10 murders and sentenced to life in prison.
The judge recommended that Rose never be released.
Charles Starkweather and Caril Ann Fugate
Eight days was all it took for Charles Starkweather to account for 10 of his 11 murders in December 1957 and January 1958.
A 19 year old Starkweather and his 14 year old girlfriend Caril Ann Fugate went on a killing rampage across Nebraska.
Starkweather suffered from a speech impediment and poor vision and was bullied at school for this. He looked up to James Dean and based his outfits and the way he acted on the Hollywood actor.
Fugate's mother and stepfather didn't approve of the schoolgirls relationship with Starkweather and banned him from seeing her. Following this, Starkweather proceeded to shoot Fugate's parents to death and strangled their two year old daughter. When Fugate arrived home, seeing her family members dead, she reportedly watched TV while Starkweather made sandwiches and wrapped the corpses in old newspapers.
Their spree was so depraved that the couple killed two teenagers in their car for just $4.
At their trial, Fugate claimed she had been held hostage by Starkweather, but the jury discounted her story and she became the youngest person to be tried for first-degree murder.
Fugate was sentenced to life while Starkweather received the death penalty. He died in the electric chair on 25th June 1959.
Fugate served just over 17 years of her sentence and was released in 1976.
Daniel and Manuela Ruda
"It was not murder. We are not murderers. It was the execution of an order," stated Manuela Ruda. "Satan ordered us to. We had to comply. It was not something bad. It simply had to be."
Manuela Ruda accepted the fact that she and her husband Daniel had killed a man, but to her it wasn't murder.
In 2001, Daniel and Manuela lured work colleague Frank Haagen to their flat where they attacked him with a hammer and proceeded to stab him 33 times. The couple carved a pentagram on to Haagen's chest and drank his blood before having sex next to his body.
Manuela claimed she had become interested in devil worshipping after spending time in Britain where she had worked as a chambermaid in her teens.
Daniel met Manuela after she posted a lonely hearts advert: "Vampire seeks princess of darkness that hates everyone and everything."
In 2002 Daniel was jailed for 15 years and Manuela was sentenced to 13 years.
Alton Coleman and Debra Brown
During the time Alton Coleman was due to stand trial for the rape of a 14-year-old girl, he went on a mass killing spree that claimed the lives of eight people in 1984.
Coleman was mentally disturbed and his partner in crime was 21-year-old Debra Brown. Brown was later diagnosed with a dependent personality disorder.
The heinous couples youngest victim was only nine years old, who was strangled to death while her parents were bludgeoned. Coleman and Brown were sloppy and left fingerprints at the victims house which led the FBI to order a nationwide manhunt and placed Coleman on its Top 10 Most Wanted list.
Police eventually caught up with the murderous duo and found Debra with a gun in her bag and Alton with a knife concealed in his sock.
Coleman and Brown were both given the death penalty and Coleman was executed in 2002 by lethal injection. Brown had her sentence commuted and is serving life without the possibility of parole.
Jasmine Richardson and Jeremy Steinke
Three members of the Richardson family were murdered in Canada in 2008. What was shocking is that the murders were planned out and committed by the family's 12 year old daughter and her 23 year old boyfriend Jeremy Steinke.
According to friends of Jasmine, her parents had punished her for dating Steinke due to the large age difference between the two. Jasmine's friends had also criticized her about the relationship.
Steinke had reportedly told friends of Jasmine that he was a 300 year old werewolf and told them he liked the taste of blood. He also wore a small vial of blood around his neck.
The two reportedly met on a the website VampireFreaks.com, and Jasmine's page falsely stated she was 1 and ended with the text "Welcome to my tragic end".
Just hours before committing the murders, Steinke and his friends had watched the film Natural Born Killers, about a young couple who go on a violent killing spree. Steinke had reportedly told his friends that he and Jasmine had planned a similar spree. He was also reported to have told an undercover police officer: 'You ever watch the movie Natural Born Killers?.. I think that's the best love story of all time..'
When the authorities finally caught up with the pair, Jasmine was too young to be charged with a crime. However, when she had turned 13, she was found guilty of three counts of first-degree murder. She is believed to be the youngest person ever committed of a multiple murder charge in Canada.
Under the Youth Criminal Justice Act, she was sentenced to the maximum penalty of ten years imprisonment. Her sentence included credit for the eighteen months she had already spent in custody.
Steinke admitted to the murder of Jasmine's parents in a conversation with an undercover police officer while in custody. He was tried in 2008 and was found guilty on three counts of murder for the killings of the three Richardson victims. In December of that year, Steinke was sentenced to three life terms, one for each of the murders, and he will be eligible for parole after serving twenty five years.
Paul Bernardo and Karla Homolka
Paul and Karla seemed like the perfect couple. Little did people know the horror that they would unleash.
Bernardo and Homolka commited all three of their murders shortly before tying the knot. Eerily, they also applied to have their last names changed to "Teale" in honor of a serial killer they admired from a fictional book.
Paul Bernardo originally found himself on the police radar as the "Scarborough Rapist", who committed over twenty sexual assaults in the 1980s. When Bernardo first met Homolka, she was happy to encourage his sexual deviancy and took on the role of finding young girls for Paul to assault.
The couple's first victim was Karla's youngest sister, Tammy. In 1990, Karla drugged Tammy with some anesthetics she stole from the veterinary clinic where she worked. After abusing Tammy as she was unconscious, Tammy choked to death on her vomit. Karla and Paul cleaned Tammy up and notified the police, who ruled it an accidental death.
The couple went on to drug, abuse and kill two more teenage girls and videotaping their actions before they were caught.
At trial, Karla was able to exchange a plea-bargain for a sentence of only twelve years for her role in the murders. She was offered this deal before prosecutors were made aware of the videotapes which showed her role in the murders was equal to that of Bernardo's.
Bernardo was jailed for life in 1995. Karla was released from prison in 2005 and now lives in Canada with at least three children she bore after her release.
Serial Killer Season starts Monday 13th June from 9pm