He looked harmless: The journalist who nabbed 'The Serpent'

Journalist Joseph Nathan went for food at a Kathmandu casino one night in 2003 but ended up with the scoop of his life: French serial killer Charles Sobhraj was there playing baccarat.

His resulting article in the Himalayan Times led to the arrest of Sobhraj and his incarceration -- which ended on Friday -- for just two of the smooth-talking killer's many murders across Asia in the 1970s.

"He was like an old man. You wouldn't give him a second look. He looked harmless... It was sheer luck that I recognised him. I think it was karma," Nathan told AFP in an interview.

Ending up in Thailand in the mid-1970s after a youth of travel and crime, Sobhraj was linked to more than 20 murders, many of them young foreigners on the Asian hippie trail.

Justice eventually caught up with him in India in 1976 when he was arrested and imprisoned in Delhi's Tihar jail, where he escaped after drugging prison guards but was recaptured.

Upon release, he moved to France but travelled to Nepal in 2003, apparently believing that authorities there had nothing on him, Nathan said.

Also Read | 'The Serpent' serial killer Charles Sobhraj leaves Nepali jail

However, he was still wanted for murdering two backpackers in 1975 and it was his bad luck that the Indian journalist happened to recognise him, even without his trademark beret.

"The casino manager was a friend of mine and we watched him together on the security camera," said Nathan, editorial adviser at the Himalayan Times and one of its founders.

"I posted a photographer around the clock at his hotel, which was a cheap hotel. Every night he was playing baccarat at the casino."

In the meantime Nathan dug around and managed to secure from the hotel manager a copy of Sobhraj's passport. He had checked in under an alias.

"On the 12th or 13th day I followed him into the loo and asked him if he was Charles Sobhraj," Nathan told AFP.

"He said: 'Is that a Bollywood actor?' Then I knew I had him. The same night I wrote the story... and the following day he was picked up at the casino (by police)."

Sobhraj, now 78 and with heart problems, according to his lawyer, was released from prison on Friday to be deported back to France.

Nathan said he thinks the decision is fair.

"It was time he was released as he has already served his sentence in accordance with Nepal's law," he said.

However, like other protagonists, Nathan is unhappy with the hit Netflix/BBC series The Serpent about Sobhraj's life, not least for changing the name of his newspaper.

"It was the greatest scoop," he said. "But Netflix changed the name of our newspaper in its mini-series. We contemplated suing them."