“Yes! He has a heart and I just fixed valves inside. Recovering normally. #Charles #Sobhraj.”

Heart surgeon Dr Raamesh Koirala tweeted on Monday afternoon, sending Twitter aflutter, with many praising the doctor for showing a big heart to treat a notorious criminal.

Dr Koirala also posted a pick of himself with Sobhraj, a notorious French serial killer who earned the sobriquet of “the Serpent” for repeatedly managing to slither away from the clutches of law.

A team of doctors led by Dr Koirala on Monday performed an hours-long surgery at the Shahid Gangalal National Heart Centre on Sobhraj, 73, who is doing time for the last 12 years in Nepal for two murders in Kathmandu in 1975.

“The operation was successful. He is doing fine and is under observation,” said Dr Koirala.

“I first got a call from his mother-in-law when I was holidaying in Khaptad a few weeks ago. Later, French embassy officials also requested me,” said Dr Koirala. “After discussing with my team, I decided to take charge of the complicated procedure.”

Sobhraj will be sedated for around 24 hours and under intensive care, according to the surgeon.

The French citizen with Vietnamese and Indian parentage committed a string of murders through Asia in the 1970s. Bodies of the two of his victims were found only in bikinis, hence the nickname “bikini killer”.

Sobhraj, who has been implicated in more than 20 killings, served 21 years in prison in India for poisoning a French tourist and killing an Israeli national.

He was arrested in Kathmandu in 2004 after he was first spotted in a casino.

The Supreme Court sentenced him to life in prison for murdering an American tourist, Connie Joe Bronzich, in 1975 in Nepal. In 2014, he was convicted of killing Laurent Carriere, a Canadian backpacker, and given a second life sentence.

Sobhraj married Nihita Biswas, the daughter of his lawyer, from jail.