Students of Narsingdi Polytechnic Institute con­fined their principal to his office for about four hours yesterday labelling different irregularities and corruption charges against him. Police quoting students said students of Refrigera­tion Department of the institute brought out a procession on the campus and demanded removal of Principal Sushil Kumar Barman. During agitation, the students locked the room of the principal. It is alleged that Principal Sushil Kumar embezzled a large amount of money and he misbehaved with students. Later, police from Narsingdi sadar police station brought the situation under control and released the principal. When contacted the principal refused to talk to local journalists.