An expatriate, Shahjahan Patwary, died after an alleged assault in Mandari area of Shahmahmudpur Union in Chandpur Sadar.
Local accounts said a group of youths had been carrying out an anti-drug activity in the area.
They said Patwary called out to the youths after seeing them running and asked the reason for it.
The youths then allegedly threw bricks at him, leaving him seriously injured.
He was taken to Chandpur General Hospital, where a doctor declared him dead.
Following the death, residents blocked a road in the Mahamaya area for a time.
Police went to the scene, brought the situation under control and detained one person on suspicion of involvement.
Chandpur Model Police Station officer Fayez Ahmed said police had received information that a person died during the anti-drug activity.
He said the matter was under investigation and that legal action would be taken in line with its findings.
Amena Begum, identified as a family member and local resident, alleged that people sent by former Shahmahmudpur Union chairman Swapan Mahmud were responsible for the attack.
Mahmud denied the allegation, saying he was not in the area at the time and had been attending a programme.