Seven Nepalese and five Indian inmates in the custody of Eastern Regional Prison of Sunsari district, fled the prison by digging a tunnel last night, according to the Central Police News Room.
Most of them were charged with abduction, murder, running fake currency racket and looting.
The police came to know about the jailbreak only this morning during regular checking, police sources said.
The jail administration has launched a manhunt to nab the escaped prisoners, according to Chief District Officer Laxman Kumar Thapa.