A woman accused of seducing and killing an elderly man and poisoning three others on the French Riviera has been charged and remanded in custody.

Patricia Dagorn, 53, was already serving a five-year jail sentence for theft, fraud and kidnapping concerning an 88-year-old widowed teacher.

A source in the new investigation said she was taken from prison to be formally charged with 'poisoning with premeditation' in the first case in 2011 and murder for a second death the same year in the Mediterranean city of Nice.

Murder: Patricia Dagorn was formally charged with 'poisoning with premeditation' in the city of Nice (pictured)

Charged: The 53-year-old has been accused of giving 'harmful substance' to vulnerable elderly men in the French Riveria (pictured). One of her victims said back in 2013: 'Three days of love almost cost me my life'

She also faces charges of 'administering harmful substances with premeditation to vulnerable people' in two other cases in 2011 and 2012, while a possible fifth case was still being investigated, the same source said.

Dagorn's lawyer Cedric Huissoud said: 'She denies all the accusations against her.'

Imprisoned: Dagorn was already in prison for the theft, fraud and kidnapping concerning an 88-year-old widowed teacher (stock image)

He described his client as a 'fragile' individual who had been placed with a foster family at a young age, adding: 'She says she feels better with elderly people.'

In the case for which Dagorn was jailed in 2013 police, found bottles of Valium pills and methadone at the home of her victim, a retired teacher named only as Robert.

He said at the time: 'Three days of love almost cost me my life.'

In the new cases, one of the alleged victims she had befriended in 2011 died at the age of 85.

Two other suspected victims, who live in Frejus and Nice on the Cote d'Azur, believed she tried to poison them.

The man from Frejus, who is in his eighties, said he had met Dagorn through a dating agency in 2012.

But soon afterwards his hope that he had found new love late in life was shattered when he found Valium in her case and his doctor said he found traces of poisoning in his body.