A man died after he was shot by a rival group in Brahmanbaria's Bancharampur upazila early on Tuesday.
Suman Mia, 35, was the son of late Manu Mia of the upazila's Paikarchar village where he was shot at around 1am.
He was taken to Bancharampur Upazila Health Complex where doctors declared him dead.
Five others – Abdul Awal, Kamruzzaman, Jalal Mia, Monir Hossain and Karim – were injured in the incident. They were also taken to the health complex where doctors said they should be sent to Dhaka for better treatment.
The shooting took place when supporters of Iqbal Hossain of Tatuakandi village attacked those of Oli. All the victims, including Suman, are Oli's supporters.
Iqbal and Oli have been embroiled in a long-standing dispute, locals said, adding that the cause of the row remained unclear.
The attackers also used sharp weapons.
Bancharampur Model Police Station Officer-in-Charge Salauddin Chowdhury said two people had been detained in this connection.