Luring unsuspecting victims into their 'house of horrors', Fred and Rose West's vile murder spree is still being unravelled to this day.
This week, police began excavation work at the cellar of the Clean Plate cafe in Gloucester, where a suspected teenage victim of serial killer Fred may have been buried over 50 years ago.
Detectives might try to quiz his wife, Rose, during the renewed search for 15-year-old cafe waitress Mary Bastholm, who was last seen alive in January 1968, however it's believed the teen went missing before Fred met her.
Together, the pair tortured, raped and murdered at least 12 people over a 20-year period, torturing them in their 'sex dungeon' and burying them in their cellar and garden.
Grooming Rose as an underage teen, Fred invited her to live with him and the couple indulged in decades of dark, depraved fantasies - beating and abusing their own children, while inviting scores of lovers into their home for increasingly violent sex games.
But when their luck ran out, so did the sordid passion that fuelled their crimes, as Rose cast Fred aside in an attempt to save her own skin - leading to his suicide weeks before their trial.
Killer groomed 15-year-old lover at bus stop
Before he even met Rose, Fred had already set off on his murder spree.
Alienated from his first wife, Catherine 'Rena' Costello, who fled from his heavy physical abuse, the killer struck up a relationship with Anne McFall, a 16-year-old 'nanny' to his daughter Anne Marie and Rena's daughter Charmaine.
Later described by Fred as the “love of his life” and his “angel”, McFall was only 18 when she fell pregnant with his child - before vanishing in 1967.
Her dismembered body was not found till June 1994, when it was dug up in Fingerpost Field, yards from Fred's parents’ house. While he initially denied killed McFall, he is said to have confessed to a visitor years later in jail.
Two years on from Anne's death, Fred, then 27, met Rose at a bus stop days after her 15th birthday. Despite his 'tramp-like' appearance the pair struck up a bond over an "insatiable desire for sex" as he lavished her with gifts.
Rose soon became a frequent visitor at the Lake House Caravan Park where Fred lived with his children.
Fearing she was engaging in prostitution, her mother and father - who is believed to have molested her as a child - called social services and placed her in a home for troubled teenagers.
Yet after her 16th birthday, she returned to Fred - by now living in a flat in Cheltenham - and started to display horrific violent tendencies of her own.
Rose's bloodlust grows
When Fred was jailed for 10 months for petty theft, Rose was left in charge of her two step-daughters and her own child, Heather Ann, whom she gave birth to in 1970.
It was during this period that Rose committed her first murder, killing eight-year-old Charmaine and stashing her remains in the cellar for Fred to bury in the garden upon his release.
Writing to Fred in prison at the time, she wrote: “Darling, about Char. I think she likes to be handled rough. But darling, why do I have to be the one to do it. I would keep her for her own sake, if it wasn’t for the rest of the children.”
When Rena called to their home to question the whereabouts of her daughter two months later, Fred strangled her and dumped her mutilated body in Gloucester's Letterbox Field.
Anne Marie later opened up on the horrific abuse the children suffered under the care of Fred and Rose.
Aged just eight, she was stripped before being tied to a mattress, gagged and raped by her dad.
Afterwards Rose assured her: "Everybody does it to every girl. It's a father's job. Don't worry, and don't say anything to anybody."
Anne Marie later recalled them being "so, so kind" after the rapes and giving her "salty baths".
Chilling torture in 'sex dungeon'
Fred and Rose married in January 1972 and after Rose fell pregnant with their second child, Mae June, the family moved into 25 Cromwell Street - later to be known as the 'house of horrors'.
Here, Rose began working as a prostitute, inviting men and women into their home for increasingly brutal sexual games, while Fred joined for threesomes and watched extreme pornography including bestiality and child abuse.
Stephen West was born in 1973 and the kids were subject to further grotesque violence, often running away from home only to be beaten on their return.
Between 1972 and 1992, the children were admitted to A&E 31 times - but the injuries were explained away as 'accidents'.
The couple's depraved cravings, however, continued to intensify. Fred created a 'sex dungeon' in the basement of Cromwell Street, and they began luring victims into their home.
After Caroline Owens, the first person they ushered into their den, was gagged, bound and raped, she managed to flee and contact the police.
However, too humiliated to give evidence, her escape only saw the pair charged with indecent assault.
Beginning with 19-year-old Lynda Gough, the Wests decided to embark on a chilling killing spree to stop their victims speaking out like Owens.
Torturing and suffocating a string of young girls in the basement, they dismembered them before burying them in the cellar and garden.
Forensic psychologist Dr Julian Boon later commented: "The thing that haunts me the most was a mask that had nothing but two nose holes so the person can breathe but they can't see or hear.
"As a consequence they could have anything done to them and that is very frightening."
Daughter's grim murder unravels plans
As their spree continued, Rose gave birth to a number of children believed to be from lovers invited into the home.
However, it was the death of the Wests' own daughter, Heather, in 1987 that saw their sickening secret finally exposed.
One day Heather's siblings went to school, only to be told that the 16-year-old had left home upon their return.
At first Fred and Rose said she'd taken a job at a holiday camp in Torquay, then claimed she'd eloped with a lesbian lover and that she was involved in credit card fraud.
In fact they had murdered and dismembered their first-born - later taunting their children by saying if they misbehaved they'd end up 'under the patio' like Heather.
Following an anonymous tip-off accusing Fred of raping a 13-year-old girl in 1992, police raided the house - but he was released after the girl decided not to testify.
It was not until 1994 that police decided to dig up the garden on a hunch - sensing defeat, Fred guided them to his daughter's grave.
He claimed to have strangled her in a fit of rage, cut up her body with a serrated knife from Iceland, stored her remains in a dustbin and buried her body.
Rose's icy rejection sends Fred into depression
As the bodies piled up and Fred and Rose were arrested over multiple murders, the couple's sordid romance turned sour.
Brushing off her husband's affectionate touches in court, deluded Rose assumed the persona of a grieving mother and turned against her accomplice, who had attempted to take the rap for the killings.
Fred's solicitor, Howard Ogden, said: "She was stony-faced and cold and that was a big shock to Fred.
"He thought she would be desperate to embrace him and be so grateful for taking the rap but in fact she was hoping to save her own neck."
Fred, who had previously fully admitted he was the one responsible for the deaths, suddenly started to reply "no comment" when police asked for more information.
This had devastating consequences for Rose, who could no longer claim Fred had been the only one responsible as the evidence stacked up against her.
Increasingly depressed, Fred pleaded with Anne Marie and Stephen - the two of their children to visit him in prison - to tell Rose he loved her, but her icy silence saw him sink into depression.
Weeks before the couple's murder trial was due to start, Fred was found dead in his prison cell after hanging himself on January 1, 1995.
The final line of his suicide note read: "In loving memory. Fred West. Rose West. Rest in peace where no shadow falls. In perfect peace he waits for Rose, his wife."