Sabrina Kouider and Ouissem Medouni were convicted of murdering Sophie Lionnet last month
A couple in Britain have been sentenced to life for killing their au pair over a bizarre obsession with an ex-Boyzone pop star.
Sabrina Kouider (35) and Ouissem Medouni (40) were convicted last month of murdering Sophie Lionnet in in London after her burned remains were found in their garden.
The pair appeared in the dock at the Old Bailey on Tuesday and were told they face a minimum term of 30 years in prison.
The 21-year-old French nanny was starved and tortured by the couple in the weeks leading up to her death in September last year.
She was beaten and tortured by her employers, after being accused of being "in league" with Kouider's ex-partner Mark Walton, a founding member of the Irish boy band Boyzone.
Fashion designer Kouider, who is currently undergoing psychiatric treatment, and former banker Medouni interrogated their nanny for hours to extract some sort of "confession" to confirm their "perverted suspicions", dunking her head in a bath.
Within hours, she was dead.
Her body was then thrown on a bonfire in the garden as the pair barbecued chicken at their home near Wimbledon.
Miss Lionnet suffered a fractured jawbone hours before her death, and is also known to have suffered bruising and fractures to her sternum and ribs between 36 hours and three days before dying.
Judge Nicholas Hilliard QC told the pair: "It is plain from all the evidence that Sophie was a kind, gentle and good natured girl."
He said the allegations she was plotting with Mr Walton to abuse the family were a "complete fiction" and no reason for the "horrible cruelty" and "humiliation" the defendants exacted on Miss Lionnet during taped interrogations before her death.
"The suffering and the torture you put her through before her death was prolonged and without pity," he said.
In a previous statement, Miss Lionnet's mother Catherine Devallonne branded the couple "monsters" and told them: "No one, no God will ever forgive you both for what you have done to my daughter... You are equally as evil as one another."
The couple, who are both French nationals, later admitted disposing of Miss Lionnet's body but denied her murder, blaming each other for her death.
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.
He said her behaviour towards the victim was "entirely driven by Ms Kouider's mental illness in her desperation to obtain evidence of Mr Walton's abuse".
Kouider reported her former partner Mr Walton to police more than 30 times and received a caution for calling 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.
Mr Walton categorically denied the allegations against him.