KATHMANDU, Nepal (AP) — Confessed French serial killer Charles Sobhraj, who was convicted and sentenced to life in prison in Nepal, was ordered Wednesday to be released because of poor health, good behavior and having already served most of his sentence.

The Supreme Court ruling also said he had to leave the country within the next 15 days but did not specify to where.

He was serving two life sentences in Nepal for the murders of American and Canadian backpackers. Life sentences in Nepal are 20 years.

The court document said he had already served more than 75% of his sentence, making him eligible for release, and he has heart disease.

The Frenchman has in the past admitted killing several Western tourists and he is believed to have killed at least 20 people in Afghanistan, India, Thailand, Turkey, Nepal, Iran and Hong Kong during the 1970s. However, his 2004 conviction in Nepal was the first time he was found guilty in court.

Sobhraj was held for two decades in New Delhi’s maximum-security Tihar prison on suspicion of theft but was deported without charge to France in 1997. He resurfaced in September 2003 in Katmandu.

His nickname, The Serpent, stems from his reputation as a disguise and escape artist.