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A MAN and a woman were charged with murder this morning after a badly burned body was found in the suburban garden of their $1.54 million London home.

Detectives detained the pair as they investigated the disappearance of an au pair - the woman charged, Sabrina Kouider, is thought to be the ex-girlfriend of an Irish pop star, The Sun reports.

Police were trying to identify the charred remains of a body, found by firefighters called to the south London property.

A young French woman, named locally as Sophie Lionnet, is understood to have been working at the house caring for Kouider's children - but had not been seen for weeks.

Sophie Lionnet was allegedly murdered.
Sophie Lionnet was allegedly murdered. Facebook

Police were called to the Edwardian end-of-terrace house after neighbours described noticing a "weird barbecue'' in the grounds of the property and a "foul-smelling smoke".

An eight-year-old boy is said to have climbed a fence and saw a man throwing sticks onto a bonfire, reports the Mail Online.

His mum, 51, whose home backs on to the garden where the body was found said they had seen a bonfire and her two sons had seen a man sweeping wood onto the fire.

The nanny, from Troyes in north-eastern France, looked after Sabrina's two young children - including a son, six, she had with ex-boyfriend Mark Walton, who was a founding member of Irish boyband Boyzone and now lives in LA, and a three-year-old daughter - for 14 months but had struggled to settle in.

Neighbours told the Mail Kouider had allegedly been paying the nanny $A85 a month, while she regularly posted pictured of herself enjoying a busy social life on social media.

A friend said the nanny had moved to the UK to learn English but had struggled, adding: "She had finally decided to go home and asked her mum to send her$A68 so she could afford the fare.

"She was supposed to have gone back on Monday. She never arrived."

A friend of Sophie's at her old school, the Andre Malraux Paron College in Paron, around 112kms south east of Paris, recalled a "happy, socially aware young woman who everybody loved".

The source said: "Sophie had a social conscience of somebody who was far older. She took up all kinds of causes, and wanted to make a difference.

"She was bright and good at sport, and dreamed of making the world a better place. Sophie did well in her studies, and wanted to travel."

Sophie never made it back to France.
Sophie never made it back to France. Facebook

A police statement said the body was too badly burned to establish gender and age.

Ouissem Medouni, 40, and Kouider, 34, who live together, were arrested after the grisly find in a southwest London suburb. They have now both been charged with murder and appeared at Wimbledon Magistrates Court this morning.

Kouider is charged with the murder of a victim unknown on or before September 20 at an address on Wimbledon Park Road.

Medouni is charged with the murder of a person unknown between September 7 and September 20 within the jurisdiction of the Central Criminal Court.

Both the defendants wore grey prison issued track suits and Kouider was gasping for breath and on the verge of tears during the hearing. They were both remanded in custody.

Wealthy Kouider works as a stylist, make-up artist, fashion designer and songwriter.

Sabrina Kouider has been charged with murdering her nanny.
Sabrina Kouider has been charged with murdering her nanny. Facebook

A neighbour who lives above the flat told the Standard: "We complained to our landlord the day before about a bad smell. It was like a gas leak. He came in and had a look around but didn't see anything.

"That family kept to themselves mostly, I remember once they came in complaining about our washing machine leaking into their flat."

They added they had heard arguing from the flat below from time to time.

Det Insp Richard Leonard said: "Indications are that attempts were made to dispose of the body."

Jamie Patel, whose husband runs a newsagent yards from the house, said: "The nanny was quite attractive - a slim and quite timid French girl."

Jaime's husband Sunny said: "She came in nearly every day to buy milk or sweets for the lads but hasn't been seen for two or three weeks."

Ms Kouider, of French Algerian descent, is understood to be estranged from her French husband.

Locals said Ms Kouider employed a nanny to care for her two boys - one in nursery and the other in primary school - while working in nearby Battersea.

This article originally appeared on The Sun and has been republished here with permission.