(NewsNation) — Charles Sobhraj, also known as “The Serpent,” became a free man Dec. 24.

Sobhraj has been accused of killing nearly two dozen tourists around Asia in the 1970s. A recent photo of a woman sitting next to Sobhraj on an airplane headed to France, where he’ll begin his new life, has since gone viral.

Journalist Jairaj Singh shared the photo to Twitter with the caption, “That awkward moment when you realise you’re sitting next to a serial killer who claimed at least 30 lives.” As of Wednesday night, the tweet had been viewed more than 660,000 times.

French serial killer Charles Sobhraj sits in an aircraft from Nepal to France, on December 23, 2022. (Photo by Atish Patel/AFP via Getty Images)

His French lawyer, Isabelle Coutant-Peyre, told The AP that Sobhraj will contest his conviction in Nepal, describing him as an “optimist” and resilient after nearly 20 years behind bars.

French filmmaker Jean-Charles Deniau, who escorted Sobhraj out of the Paris airport and is releasing a film and book about his life, said, “He’s doing well. He has medicines. He will live in Paris, and a little bit everywhere.”

The French government did not respond to requests for comment on whether Sobhraj could face judicial challenges in France. Sobhraj was born in Vietnam during French rule and claims French citizenship.

Sobhraj is believed to have killed at least 20 people in Afghanistan, India, Thailand, Turkey, Nepal, Iran and Hong Kong between 1972 and 1982. He reportedly befriended his victims, gave advice on where to dine, and sometimes let them stay at the apartment in Bangkok he shared with his girlfriend before killing them.

But despite multiple legal cases opened against him, judicial authorities across the region struggled to convict him for the killings — or to keep him behind bars.

He was arrested in New Delhi in 1976 and accused of murdering two tourists and stealing their jewelry. He was convicted of the theft but acquitted of murder. In Thailand, he faced 14 murder charges. He avoided being extradited by staying before the courts in India until the Thai case expired in 1996. In Thailand, he faced the death penalty.

In 1986, he escaped from New Delhi’s maximum-security Tihar prison after luring guards into sharing a drug-laced birthday cake, but was later recaptured.

In 1997, he was deported from India to France, where he lived freely but was investigated for allegedly trying to poison a group of French tourists in India.

He resurfaced in 2003 in a casino in the Nepalese city of Kathmandu, and was questioned about the unsolved murders of an American and a Canadian backpacker whose charred bodies were found on the city’s outskirts. He was convicted the following year and handed a life sentence — which, in Nepal, is only 20 years.

Sobhraj insisted on his innocence in that case, though had in the past spoken of killing other tourists. When he was released from the Indian prison, he said he regretted aspects of his past.

In announcing his release this week, the Nepal Supreme Court said Sobhraj has heart disease. They also said he had already served more than 75% of his sentence, and had behaved well in prison, making him eligible for release.

He was freed Friday and ordered to leave Nepal within 15 days. A friend helped him finance a ticket to France, and the French Embassy prepared travel documents allowing him to leave, attorney Gopal Siwakoti Chitan said.

Coutant-Peyre, his French lawyer, welcomed his release.

“I’m very happy but very shocked that it took 19 years to obtain his normal freedom,” Coutant-Peyre said at the airport. She also said his murder conviction in Nepal was based on a “fabricated case,” and said the French government didn’t do enough to help or defend him.

Coutant-Peyre also said Sobhraj watched the series “The Serpent,” which traces how Dutch diplomat Herman Knippenberg initiated an international investigation into Sobhraj’s alleged killings. He called it “garbage,” she said, and told her “70% of it is totally false.”

Sobhraj’s “serpent” nickname stems from his reputation as a disguise and escape artist. He was also known as “the bikini killer” because he often targeted young women.

The Associated Press contributed to this report.