A couple who tied up and killed their flatmate "for perverted pleasure" in a sadistic and prolonged knife attack have both been jailed for at least 26 years.
Jack Williams, 21, and Kayleigh Woods, 23, remained calm in the dock at Warwick Crown Court as they were jailed for life and told the minimum term they must serve for the murder of Bethany Hill.
Miss Hill, who had a history of self-harm, was found dead by a police officer in a blood-drenched bathroom at a flat in Stratford-upon-Avon on February 3 last year.
A three-week trial heard a knife was used to repeatedly cut Miss Hill's neck after her wrists were bound with duct tape, while a "fetish" doll with tape over its mouth was later found in a box belonging to Woods.
Passing sentence on the killers, Judge Richard Griffith-Jones said he saw no reason to draw a distinction between the couple, or to rule whether one of them had been the "controlling force" behind the murder.
Describing Miss Hill, 20, as a vulnerable victim, the judge told the defendants: "There are possibilities that the motivation for this killing may have had a sexual aspect.
"The evidence which supports that possibility relates to the doll, the duct tape and the complex web of relationships between the defendants, the deceased and one another."
Although the judge said he could not be sure that sexual gratification had played a role in the murder, he added: "The evidence compels me to the conclusion that this was a sadistic killing.
"The evidence which so compels me is the duct tape in the bath and the length of time over which this terrible, cruel attack took place - the length of time being, in my judgment, well over an hour, getting towards an hour and a half."
The judge said he was unable to accept a plea to treat Woods more leniently on the grounds she had been a "secondary party" who had assisted and encouraged her partner to carry out the fatal attack.
Williams and Woods both denied murdering Miss Hill at the flat in Hertford Road, Stratford.
During his opening of the case at the start of the trial, prosecutor Stephen Linehan said Woods was brought up as a boy but now identifies as female, having changed her name to live as a woman.
The court also heard that Miss Hill was a former girlfriend of Williams and had a "volatile" relationship with Woods, who she had planned to have a child by.
Speaking outside court after the life sentences were imposed, Detective Inspector Neal Candelent criticised Woods and Williams for showing no remorse since the killing.
The officer said: "Bethany's murder was a premeditated, cold-blooded killing of an entirely innocent young woman in the prime of her life.
"We may never fully know what happened in the hours leading up to Bethany's death. What we do know is that she was held against her will before being brutally murdered.
"I would like to pay tribute to Bethany's family - throughout the trial they have shown immense dignity and courage, and also in the weeks and months since."