The inmate, escorted by two policemen for production in a Civil Court in a case of stabbing, managed to free his hands from cuff and ran away near the bus stand, Superintendent of Police Rajiv Ranjan said.
The escapee Gopal Rishidev is a resident of Bhavaniganj under Kochadhaman police station.
Chowkidar Madan Rai and constable Rajendra Kumar were escorting him, the SP said, adding that action would be initiated against policemen for dereliction of duty.
A search was on for the escapee undertrial, Ranjan said.