Two Bangladeshi nationals were today detained on suspicion of their involvement in the sexual assault of a 71-year-old nun at a Ranaghat convent school six days ago, police said.

North Dinajpur Superintendent of Police SW Reza said that the two -- Mukul Alam (28) and Md Majid (29) -- bore striking resemblance to those caught on the CCTV camera at the Convent of Jesus and Mary school on March 14, one of them having 75 per cent similarity.

The two, both residents of Bangladesh's Thakurganj district, were picked up by the police from Bhatol village in Raiganj police station area, the SP said, adding CID officers were interrogating them.

With this, 17 persons have been detained till today in the incident.