A delusional couple have been found guilty of killing their French nanny over a bizarre obsession with an ex-Boyzone popstar.
Sabrina Kouider, 35, and Ouissem Medouni, 40, built a warped fantasy around music mogul Mark Walton and accused Sophie Lionnet of being in league with him.
Kouider collapsed in tears as the jury foreman returned the verdicts, while Medouni hung his head.
Miss Lionnet's mother Catherine Devallonne also wept as Judge Nicholas Hilliard QC said he was sure the allegations against her daughter had "no truth whatsoever".
In the weeks leading up to her death in September last year, the couple beat, starved and tortured the shy 21-year-old au pair by dunking her head into water until she confessed.
Having killed her in the bath, the pair threw her on a bonfire in the garden of their home near Wimbledon, south-west London, as they barbecued chicken nearby.
When firefighters were alerted by neighbours to pungent-smelling smoke, Medouni tried to pass off the charred remains as a sheep.
And Kouider claimed to police that Miss Lionnet had run off with Mr Walton in an attempt to frame him for her disappearance.
The defendants later admitted disposing of her body but denied Miss Lionnet's murder, blaming each other for her death.
An Old Bailey jury found both of them guilty of the murder following a two-month trial that was described as stranger than fiction.
Miss Lionnet's parents travelled from France to see the disturbing evidence as it unfolded.
The court heard how fashion designer Kouider was fixated with her ex-boyfriend Mr Walton.
After splitting up after two years, Kouider reported him to police more than 30 times and received a caution for branding him a paedophile on a fake Facebook profile.
She also accused him of sexually abusing a cat, using black magic and hiring a helicopter to spy on her.
Giving evidence, LA-based Mr Walton said he had been "in love" with Kouider but she would "flip" and go "crazy" for no reason.
Another ex-boyfriend Anthony Francois described her as a "lunatic, fickle and unstable".
The mother-of-two created a fantasy world casting Mr Walton as an evil villain who seduced Miss Lionnet with sex and promises of Hollywood stardom.
Banker Medouni became an ardent believer in Kouider's twisted reality and they interrogated Miss Lionnet for hours to get to "the truth".
Jurors heard more than eight hours of recordings in which Miss Lionnet was slapped, likened to a Nazi collaborator and called "worse than a murderer" by her tormentors.
Kouider, who claimed to know influential people including US President Donald Trump, threatened to have her locked up and even marched her to a police station.
The victim's distraught mother Catherine Devallonne had begged Kouider to send her daughter home but she refused.
In her final days, Miss Lionnet was hit with an electrical cable and beaten so badly she had five broken ribs and a cracked breast bone.
In a filmed "confession", the emaciated and broken young woman admitted she had drugged Medouni so Mr Walton could sexually assault him. Within hours, she was dead.
According to Kouider, Medouni tortured her in the bath, then demanded they have sex as her dead body lay nearby.
She told jurors: "He was putting her head under the water and sometimes he would put water on the towel in her mouth. It was getting really mad."
Before the trial, Medouni claimed Miss Lionnet died by accident after he punched her during an interrogation in the bath.
He offered to admit manslaughter but later retracted his confession, saying he made it to protect his wife, who has been diagnosed with a borderline personality disorder.
In his evidence, Medouni claimed his wife had woken him up in a state saying "what have I done, what have I done".
He was shocked to find Miss Lionnet unconscious in the bath and tried to revive her, he claimed.
He said Kouider refused to call 999 and told him they would "burn her" instead.
A witness in the house, who cannot be identified for legal reasons, placed both defendants in the bathroom with Miss Lionnet on the night of her death.
He described hearing Miss Lionnet screaming and splashing in the bath as they said to "breathe".
Prosecutor Richard Horwell QC told jurors that neither were prepared to admit the truth - that they killed her out of "revenge and punishment".
He said their "unhealthy, myopic, all-consuming and groundless" obsession with Mr Walton had deprived them of reason and turned their nanny into "something less than human".
The judge is expected to sentence the pair on June 26 at the Old Bailey.