The publication of his book Autobiography of a Sadhu: A Journey into Mystic India, later added to the mystery.

BBC: The foreign Hindu monks at India's Kumbh Mela

One well-known sadhu, Parbat Giri, from Ahmedabad in the western Indian state of Gujarat, said the Mela was important because of the sense of community it gave holy men from different orders.

BBC: Hindus take plunge at special Kumbh