In 1994 in Gloucester, England, police visited 25 Cromwell Street, acting on a tip from social services regarding a horrifying rumor they were told by the children of the couple who lived there, Fred and Rose West. If they misbehaved, the children said, they’d end up under the patio like their sister, Heather, who had not been seen since 1986. Police would eventually uncover not only the murdered and dismembered remains of Heather, but also eight additional bodies buried in the garden and cellar.

So begins the investigation uncovering one of the most heinous and heartless murder sprees in modern history. Fred and Rose West: A British Horror Story tells how a couple who were, to those who observed them, in a loving, committed relationship could be capable of such gruesome crimes.

Through 107 police interview tapes covering over 50 hours of interrogations, much of it previously unseen and -heard, this three-part docuseries sheds new light on the notorious murders of at least 12 women.

Who are Fred and Rose West?

The Wests were a married British couple who lived at 25 Cromwell Street in Gloucester, England, with their ten children, as well as tenants who rented a spare room. Fred was 27 years old when he first met Rose, who was 15 at the time, and working in a cake shop in the nearby town of Cheltenham. She became pregnant a month after her 16th birthday. A former tenant described Fred as “absolutely besotted with Rose”; another tenant, Alison Chambers, wrote to her family describing the couple as “loving.”

To police, Fred described their relationship as two people acting “as one.”

“I trained Rose to do what I wanted. That is why our marriage worked out so well. […] She just blended into my way of living,” Fred stated in police tapes.

But their outwardly loving life hid a shared sexual sadomasochism that began with Fred asking Rose to have sex with other men as he watched from another room, and eventually led to the kidnapping, torture, rape, killing, and dismemberment of 12 people. Their own children described Rose as physically abusive behind closed doors, who punished them in appalling, cruel ways; two daughters accused Fred of sexual abuse.

While Fred had initially insisted that Rose had nothing to do with his crimes, it became clear that Rose was not only aware of what happened, but was heavily involved. In the documentary, a neighbor recalled that Rose had confessed that she would join Fred to cruise for vulnerable women, because having a woman in the passenger seat made it easier to lure women into the car. This was later confirmed by a former nanny, Caroline Owens, who may have been one of Fred and Rose’s first victims; during the trial, she recalled how she was kidnapped, sexually assaulted, and held against her will by both Rose and Fred, who threatened to kill her. Owens managed to escape, and survived.

Fred maintained Rose’s innocence until a few months before the trial, when she began to publicly distance herself from him. He died by suicide while in prison, a month before pretrial proceedings. Rose West was found guilty of ten murders, and was sentenced to life in prison.

The known victims from top-left to bottom-right: Heather West, Shirley Robinson, Alison Chambers, Thérèse Siegenthaler, Shirley Hubbard, Lucy Partington, Juanita Mott, Lynda Gough, Carole Ann Cooper, Catherine “Rena” Costello, Ann McFall, Charmaine West

How many people did Fred West and Rose West murder?

While being questioned by police, Fred confessed to at least 12 murders, the earliest of whom was Ann McFall, a nanny he employed in 1967 while he was married to Catherine “Rena” Costello to care for their child, Charmaine West, both of whom were also murdered.

The remains of nine women were found buried at 25 Cromwell Street, including Fred and Rose’s daughter Heather and a tenant, Shirley Robinson, who was eight months pregnant with Fred’s child. Fred and Rose targeted young, vulnerable women who were often runaways or without guardians. They include Alison Chambers, Thérèse Siegenthaler, Shirley Hubbard, Lucy Partington, Juanita Mott, Lynda Gough, and Carole Ann Cooper.

Where is Rose West now?

Shortly after being found guilty, Rose attempted to appeal her convictions, but her application for appeal was refused. Rose is currently serving her life sentence at HM Prison New Hall. She continues to maintain her innocence.