District Superintendent of Police Arnab Ghosh on Monday said seven to eight persons were involved in the crime and it is now being ascertained whether the detained resemble the persons seen in the CCTV footage at the convent and their antecedents were being checked.
Extensive searches are on to trace those behind the crime, he told reporters, adding "Details of the police investigations into the crime cannot be given for the sake of investigation."
The CCTV footage at the convent had shown visuals of four persons, who were allegedly involved in the crime. The SP had announced a reward of Rs one lakh to any individual providing credible information leading to the arrest of the accused.
Director General of Police G M P Reddy, who visited the convent during the day, said investigation is on into the crime that took place in the early hours of Saturday last. Chief Minister Mamata Banerjee, who had promised "swift and strongest action against the culprits", is scheduled to visit the convent this afternoon.
CID is planning to extend its search for the culprits in other states
District Magistrate P B Salim visited the Sister Superior of Convent of Jesus and Mary, who was allegedly brutalised, at Ranaghat Hospital. She was stable, he said. DIG, Murshidabad range Kallol Gonai also visited the school, where CISCE examinations were on peacefully.
CID, which has been entrusted to look into the investigation into the crime by Banerjee, is planning to fan out to other states in search of the culprits, an official in it said on condition of anonymity.
ADG CID Rajeev Kumar is directly monitoring the case. Roman Catholic Archdiocese of Calcutta would take out a rally in Kolkata during the day to express solidarity with the nun.