A case has been filed against 21 BNP men, naming 10 BNP activists, over an attack on a Jamaat-e-Islami leader in Sirajganj on Saturday.
Shohar Bhanu, wife of the victim Abdus Sabur, filed the case with Sadar Police Station on Saturday night, said Rakibul Hasan, officer-in-charge of the police station.
Police have already launched an operation to arrest the accused, the OC said.
He said Jamaat activists gathered in the Saydabad area on Saturday afternoon to welcome the motorcade of the 11-party alliance's Dhaka-Rangpur long march.
After the procession proceeded towards Rangpur, the Jamaat activists were returning home when a group of people attacked Abdus Sabur and hacked him, leaving him seriously injured.
Another Jamaat leader, Nurnabi, was also beaten during the incident, the OC said.
Abdus Sabur has been admitted to Shaheed Ziaur Rahman Medical College Hospital in Bogura in critical condition.