The deceased was identified as Tarek Rahman, 14, son of Shahid Morol and student of Jhikargasa Dargah Madrasa.
Inspector of Rajganj Police investigation center Tarikul Islam said Tarek had been spending pandemic-induced holidays with his family.
He wanted to go out in the morning but his mother asked him to study and threatened to inform the madrasa teacher if he disobeyed.
Being agitated, Tarek locked his mother in the house and hung himself from the branch of a tree in their premises.
The body of the boy was handed over to his family without post-mortem examination on their request, police said.