Mizanur Rahman, a citizen rights activist, was released six hours after he was picked up from Jurain in the capital on Thursday.
He was released from the DB Headquarters on Mintoo Road at around 4:45pm.
AKM Hafiz Akhter, additional commissioner (DB) of Dhaka Metropolitan Police (DMP), said they did not arrest him. They took him to the DB office to just talk to him over some issues, he said.