Multi-millionaire religious "guru" Gurmeet Ram Rahim Singh persuaded around 400 of his estimated 50 million followers worldwide to cut off their own testicles to "bring them closer to God".
The details of the bizarre incident have only just come to light despite reportedly taking place in 2000 at a hospital run by Ram Rahim in India.
India's Central Bureau of Investigation has reportedly accused Ram Rahim of grievous bodily harm and he is under investigation. He has previously been questioned over the murder of an investigative journalist in 2002 and has also been accused of sexual assault by female followers but has never been charged.
Navkiran Singh, who is the lawyer for Hans Raj Chauhan, the only castration victim so far to come forward, said his client and other victims believed they would become social outcasts if they refused to perform the "operation" demanded of them by Ram Rahim.
"They were told that only those who get castrated will be able to meet God," said Navkiran, in a report in the Daily Mail.
Ram Rahim, 47, dubbed the "guru in bling", is head of the socio-political organisation Dera Sacha Sauda and is estimated to be worth £26m.
The guru stars in a spectacular new movie, Messenger of God, in which he appears to walk on air, tear tree trunks in half and perform other miracles. Though 157,000 people are thought to have attended the film's premiere in Gurgaon, near Delhi, according to the Sydney Morning Herald, the revelations have caused sales of tickets for the movie to dwindle dramatically.
Gurus are big business in India, where their endorsements can help political parties get elected, and where millions of people seek spiritual guidance every year. Sathya Sai Baba, who was said to be able to conjure ash from thin air, was worth an estimated US$7bn when he died.
Even after death, some gurus retain a hold over devotees. Ashutosh Maharaj, who was certified deceased by medical examiners last year, has had his body frozen by followers who apparently believe he is merely in a state of deep meditation called "samadhi".