Serial killer The Serpent, Charles Sobhraj, to be freed from Nepal jail

Charles Sobhraj has been held in a high security prison in Nepal since 2003

A French serial killer portrayed in BBC drama The Serpent is to be freed from a Nepalese prison, after a court ruling.

Charles Sobhraj, who spent 19 years in jail for the murder of two tourists in Kathmandu in 1975, has been ordered to return to France within 15 days.

Sobhraj was linked to a string of other tourist murders in the 1970s, and spent 20 years in prison in India.

His victims were mostly young Western backpackers on the hippie trail in India and Thailand.

The notorious killer had been serving two life sentences, each 20 years, in Nepal's capital for the murder of an American woman, Connie Jo Bronzich, and her Canadian backpacker friend, Laurent Carriere.

He was convicted in two separate trials - most recently in 2014, when he was sentenced to 20 years in a high security prison for murdering Carriere.

But Nepal's Supreme Court ordered Sobhraj's release on Wednesday after his legal team successfully filed a petition claiming he should be given a concession on his prison term due to his age, 78, and good behaviour.

A provision in Nepalese law allows inmates who have shown good character and completed 75% of their jail term to be released.

"Keeping him in the prison continuously is not in line with the prisoner's human rights," the verdict read, according to AFP, and cites regular treatment for heart disease as another factor in his release. His lawyer says he could be released as soon as Thursday.

Sobhraj has been linked to more than 20 killings between 1972 and 1982, in which the victims were drugged, strangled, beaten or burned.

He was dubbed "The Serpent" or the "Bikini Killer" for his knack for deceptive disguises, ability to escape prison and tendency to target young women. It later became the title for a hit BBC and Netflix series about the killer, which was released in 2020.

Prior to his two convictions in Kathmandu, Sobhraj had already spent two decades in jail in India for poisoning a busload of French tourists.

During that time he briefly managed to escape from prison by drugging the prison guards. He later claimed the escape was a ploy to get his sentence extended and avoid extradition to Thailand where he was wanted for five more murders.

Following his release from India, Sobhraj was arrested for Bronzich's murder after being spotted in a casino in Kathmandu in 2003.