Nine Bajrang Dal activists, including some of its leaders, have been named in the FIR lodged in connection with the Sunday's incident, in which a congregation of 20-25 people of Christian community was attacked.
Security has been beefed up around the area in view of the incident.
Rohtas SP NH Khan said that named FIR had been lodged under various sections, including SC/ST Act, on the basis of the statements of the victims.
"All of them are absconding, but we are after them. They will soon be arrested," he added.
Khan said that two persons had sustained minor injuries in the incident. "All of those who had gathered there for the prayer at the Postal Colony were from outside.
They had taken a room on rent for their weekly congregation. They had come from Kargahar and belonged to Scheduled Caste community," he added.
The SP said that the Christian congregation at the Postal Colony was a usual Sunday affair. "But another group arrived there and ransacked the room, broke the musical instruments," he added.
Many dalit families, which recently embraced Christianity, had to face the wrath of about three dozen persons, allegedly owing allegiance to Bajrang Dal, when they attacked a prayer meeting in Postal Colony in Patna on Sunday morning. Holy books were also reportedly set on fire and furniture damaged in the incident.
On getting information, the police reached the spot and brought the situation under control. Sources said about 12 newly converted Christians, who received lathi blows, were admitted to the Sasaram Sadar Hospital.
An FIR against 25 Bajrang Dal workers has been lodged with the town police station in this connection.
Additional police forces have been deployed in the area as a precautionary measure. The police described the situation as tense but under control. Raids were on to nab the culprits, said the sources.
Meanwhile, media-in-charge of Bajrang Dal denied the organisation's involvement in the attack, saying it was the result of unabated conversion by Dalits. Last week, about 20 Dalit and tribal children embraced Christianity.