"We have nabbed the prime accused in the alleged nun rape case incident yesterday," said Director-General of police Manmohan Praharaj.

With the arrest, the number of persons rounded up in the case rose to five, sources said. The main accused, identified as Somanath Pradhan of Rajaghar village under Baliguda police station in Kandhamal district, was picked up from his house on the basis of information collected by the police.

Superintendent of Police (crime branch) Yatindra Koyal said more arrests were likely to be made in the rape case very soon and the investigation was on the right track.

"All the five arrests made so far in the case were on the basis of concrete evidence available with us," he said.

The presence of the alleged victim was essential because the nun had reportedly told some private news channel that she could identify the accused in person.