Sabrina Kouider, 35, swore on the Quran to tell "the truth, the whole truth and nothing but the truth" at the Central Criminal Court — the Old Bailey — in London on Friday, April 27.
She told the court how 21-year-old Sophie Lionnet came to work for her in January 2016 after a recommendation by her brother Jamal.
The body of Sophie, who came from the French town of Troyes, was found burning on a bonfire in the back garden of Kouider's home in Southfields, south-west London in September last year.
Kouider and her boyfriend Ouissem Medouni both deny murder but admit attempting to pervert the course of justice by disposing of her body.
Sabrina Kouider, who is accused of murdering her French nanny, is an "aggressive and wild" person who had a habit of attacking other women randomly in the street, an ex-boyfriend tells the Old Bailey.— Tristan Kirk (@kirkkorner) 27 April 2018
Kouider — who is currently being held at the Bracton medium-secure mental health facility in Bexley, Kent — said there were no major problems until May 2017 when she believed Sophie had gone to a house in London and met Kouider's former boyfriend, Mark Walton, a founder member of the boy band Boyzone.
'I Felt Betrayed'
She said she felt "betrayed" and admitted "beating up" Sophie with a length of electrical flex.
"I took a cable and I started hitting her really bad," Kouider said, in answer to a question by her defense barrister, Icah Peart QC.
Kouider broke down and was on the verge of tears as she recalled this incident, only four months before Sophie died. She said she remembered Sophie was not crying but was saying "sorry" as she hit her with the cable.
The court has heard audio tapes of interrogations Kouider and Medouni performed on Sophie in the days before she died in which they persistently questioned her about the house where they believed she had gone to meet Mr. Walton.
Kouider has admitted beating Sophie Lionnet with an electric cable in May 2017 because she felt "betrayed". She denies murder— Total Crime (@totalcrime) 27 April 2018
Medouni and Kouider are both claiming they are innocent of the murder and are blaming each other for causing her death.
Kouider said she was born in al-Attas in Algeria in 1982 but moved to Paris as a child, with her family, because of the civil war which was raging at the time.
She also claimed she was sexually abused by an uncle in Algeria when she was very young.
Mr. Peart then led her through her life and asked her about when she first met Medouni, who she called Sam.
Lost Her Virginity to Co-Defendant
She said Medouni was her first boyfriend and took her virginity in 2001 when she was 19.
The couple moved to London in 2001 where he worked as a banker for Societe Generale.
But she said it was an "on and off" relationship because Medouni refused to make a commitment and failed to show up at a Muslim wedding ceremony.
In 2011 she broke up with Medouni and began a relationship with Mr. Walton, who became a successful music producer after leaving Boyzone.
She said she suffered a miscarriage after he threw her against a wall.
'She Could Be Lovable and Detestable'
Earlier the court heard a written statement by another of Kouider's ex-boyfriends, Anthony Francois, who said she was a "charming" and "manipulative" liar who suffered from wild mood swings.
"Sabrina was strange. She could be lovable and detestable. There was no reason for this change in her moods. Her behaviour was difficult. She loved attention," Mr. Francois told police in a statement in January 2018.
"She would lie. Her behavior was strange and aggressive. She pulled the hair of girls on the street just because of a look….Sabrina was reckless and wild, impulsive, moody, volatile. She had a dual personality. She knew who she targeted, always the weaker ones," said Mr. Francois.
The trial continues and a verdict is expected next week.