The Tibetan spiritual leader made the admission in the Netherlands, where he met victims of sexual abuse after they launched a petition asking to meet him during the trip.
The man had an unprotected sex with a 14-year-old girl, but the offence came under the spotlight after 2 years when the victim visited a polyclinic for a urinary tract infection.
Kerala police have ascertained through witness statements that the bishop was present in the convent on the day when the assault took place as per the nun's complaint.