The victim, identified as 35-year-old Abdul Alim of Nurpur Moholla of the municipality, is undergoing treatment at Pabna Medical College Hospital.
But the incident came to light on Monday night after Alim’s wife filed a case with the sadar police station naming 10 persons over the attack.
According to the case statement, Ariful, the younger brother of Maligachha union parishad chairman Shariful Islam Sharif, and his associates beat up and stabbed Alim.
Locals initially took him to Sadar Upazila Health Complex but he was later shifted to Pabna Medical College Hospital.
CCTV camera footage from a nearby shop showed that the officer-in-charge of Sadar police station Khairul Islam and a constable were present during the incident.
Aleya Khatun, mother of the victim, demanded justice after proper investigation into the incident.
OC Khairul declined to comment.
Additional superintendent of police, Goutam Kumar Biswas, said a three-member probe body, headed by additional superintendent of police Shamima Akter, was formed to investigate the incident.
Police also have arrested two people in this connection.