The 37-year old Utpal Kumar Sarker, a Sirajganj's Ullapara native, died at Enam Medical College Hospital in Savar on Monday morning.
The body was sent to Shaheed Suhrawardy Medical College Hospital for post-mortem examination, said Emdadul Haque, a sub-inspector at Ashulia Police Station.
Utpal was working as a lecturer of political science at Haji Yunus Ali School and College. He was also the chairman of the institution's disciplinary committee.
He lived with his family in Dhaka's Mirpur. Utpal graduated from Chattogram University and also did his master's there.
SI Emdaul said the student, a 10th grader, carried out the sudden attack at the college ground on Saturday afternoon, critically injuring the teacher.
"He [Utpal] had to correct the students many times. Maybe the student was angry at him for something like that. We’re trying to arrest him."
Principal Saiful Hasan said the student started beating Utpal indiscriminately with a stump when the teacher was watching a cricket match.
Utpal had asked students to get decent haircuts and counselled them on their behaviour many times, Saiful said. "Maybe the student attacked him because he was angry for some punishment [the teacher meted on the student."
Utpal's brother Asim Kumar Sarker demanded justice for the slain teacher. Citing students, Asim said Utpal had corrected the attacker for sexually harassing female students.