A cruel couple have been jailed for at least 30 years for torturing their French nanny to death over a bizarre obsession with a former Boyzone pop star.
Delusional Sabrina Kouider, 35, and her timid partner Ouissem Medouni, 40, killed 21-year-old Sophie Lionnet over a false belief she was in league with music mogul Mark Walton.
Over more than eight hours of recorded interrogations, the au pair was humiliated, slapped and likened to a Nazi collaborator by the pair.
In her final days, Miss Lionnet was hit with an electrical cable and beaten so badly she had five fractured ribs and a cracked breast bone.
She appeared broken and emaciated in a videoed confession hours before she was killed in September last year.
Afterwards, the defendants threw her body on a bonfire in the garden of their Wimbledon home.
When firefighters were called to investigate the pungent smell, Medouni tried to pass off the charred remains as a sheep.
Kouider went on to try to frame her ex-boyfriend Mr Walton for the nanny's disappearance to exact "revenge".
The defendants later admitted perverting the course of justice but blamed each other for killing Miss Lionnet as she was tortured with water in the bath.
A jury rejected their lies and found both of them guilty of murder following a trial at the Old Bailey.
Jailing them for life, Judge Nicholas Hilliard QC said the allegations levelled against "kind, gentle and good-natured" Miss Lionnet were a "complete fiction".
Judge Hilliard told the couple: "I'm sure on all the evidence you were both involved in torturing Sophie in the bath in the lead-up to her death in making her think she would drown unless you gave her information you wanted which was not in her power to give because it did not exist.
"The suffering and the torture you put her through before her death was prolonged and without pity."
Kouider was motivated by an unjustified desire to make Miss Lionnet and Mr Walton "suffer".
Rather than handing the taped confession to police, Judge Hilliard said they could have planned to use it to extract money from the wealthy music mogul.
The judge told Kouider: "I do not think you thought for one moment you were acting lawfully. I'm sure you knew the way you interrogated her was unacceptable in the extreme, that it was unlawful to assault her and she was in a dreadful state by the time of her death and torturing her in the bath was totally and utterly wrong."
Earlier, Miss Lionnet's tearful mother, Catherine Devallonne, said: "These self-obsessed individuals who murdered Sophie did not believe Sophie had a value.
"Those monsters repeatedly beat Sophie. They starved, tortured and broke her until she could no longer fight.
"They took away her dignity and finally her life painfully ebbed away until Sophie struggled to take her final terrified breath in the bath."
The victim's father, Patrick Lionnet, said what the couple did to his shy and reserved daughter was "beyond comprehension" and "unforgivable".
In a letter addressed "dear Sophie", Kouider acknowledged the suffering of her victim and her family, saying how "deeply sorry I am about what happened to Sophie".
She wrote they shared some "good times" until "things went terribly wrong".
"I am shocked and sad you are not part of this world anymore.
"I'm suffering every day thinking of you and what happened to you that dreadful night. I only wish I could turn the clock back, it never happened and you would be alive with us today," Kouider wrote.
Earlier in mitigation, Icah Peart QC said the fashion designer's delusional disorder coupled with an emotionally unstable personality disorder had caused her "irrational and completely overwhelming fear" that Miss Lionnet had been recruited by Mr Walton.
By the time of Miss Lionnet's death, it was Medouni who had taken over the "dominant role" in her interrogations, the lawyer argued.
But Orlando Pownall QC, said Kouider was the "dominant" party who preyed on the "weak", including his client Medouni.
He said the former banker had been "indoctrinated" by a woman with the capacity for "sudden and extreme violence".
Mr Pownall said: "But for Ms Kouider's obsession, Miss Lionnet would still be alive."
The defendants made no reaction in the dock as they were sent down.
Miss Lionnet's parents were said to be happy with the sentence but left without making a comment to waiting French and British journalists outside court.
Copyright (c) Press Association Ltd. 2018, All Rights Reserved. Picture (c) Metropolitan Police / PA Wire.