A couple who tortured their French nanny before killing her and throwing her body on a bonfire have been sentenced to life in prison.

Sabrina Kouider, 35, and her partner Ouissem Medouni, 40, were found guilty last month of murdering 21-year-old Sophie Lionnet at their home in Wimbledon, south-west London, last September. The trial heard they had a deluded belief she was in league with Mark Walton, the ex-Boyzone band member turned music mogul, with whom Kouider once had a relationship.

Sentencing the pair, Judge Nicholas Hilliard said there was no excuse for the “horrible cruelty” and “humiliation” they inflicted on Lionnet during taped interrogations before her death.



The two-month Old Bailey trial, which was described as stranger than fiction, heard how Kouider, a fashion designer, was fixated with Walton and believed Lionnet was colluding with him to drug and molest the family. Kouider even tried to implicate Walton in Lionnet’s disappearance.

The judge said allegations Lionnet was plotting with Walton to abuse the family were a “complete fiction” and motivated by a desire for revenge.

Addressing the couple in the dock, he said: “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.” He said their behaviour had its “origins in cruelty and a desire for revenge”.

The judge told Kouider she was motivated by an unjustified desire to make Lionnet and Walton suffer. He added: “It is plain from all the evidence that Sophie was a kind, gentle and good-natured girl.”

He continued: “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.”

The court heard how Kouider’s delusional disorder triggered her false belief that Lionnet had been seduced into helping Walton. The prosecution said Walton had shouldered the slurs and responded with “integrity and honesty” when he travelled from Los Angeles to give evidence at the trial.

Over more than eight hours of recorded interrogations, the au pair was slapped, likened to a Nazi collaborator and called “worse than a murderer” by the couple, the court heard.

They confiscated her identity card and phone and stopped paying her in a deliberate campaign to isolate her and force her to confess, the court heard.

In her final days, 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 filmed confession hours before she was killed in the bath.

The defendants claimed they planned to hand the tape to police as proof against Walton. But the judge suggested it was more likely they would have sent it to the wealthy mogul to force him to give them money.

When firefighters investigated pungent-smelling smoke coming from a bonfire in the couple’s garden, Medouni tried to pass off her charred remains as those of a sheep.

The defendants later admitted disposing of Lionnet’s body but denied her murder, blaming each other for her death.

Kouider acknowledged the suffering she had caused her victim and her family. In a letter, read to the court, she said she was “deeply sorry about what happened to Sophie”.

Addressed “Dear Sophie”, it said: “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.”

In mitigation, Icah Peart QC said the Kouider’s delusional disorder coupled with an emotionally unstable personality disorder had caused her “irrational and completely overwhelming fear” that Lionnet had been recruited by Walton.

He said her behaviour towards the victim was “entirely driven by Kouider’s mental illness in her desperation to obtain evidence of Mr Walton’s abuse”.