The deceased was identified as Saiful Islam Sobuj, 22, son of Faruk of a neighbouring village and student of a private college in the capital.
Locals said local union parishad member Raja had long been at loggerhead with former UP member Swapan.
When followers of Swapan were gambling on Wednesday morning, a village policeman informed the local police station over the issue.
A police team went to the spot and arrested four gamblers.
Later, Sadar Upazila Nirbahi Officer Masuma AKter conducted a mobile court and fined them TK 3,000 for breaching government’s instruction to avoid mass gathering amidst Covid-19 outbreak.
Later around 25 followers of Swapan carried out an attack on followers of Raja at Raibhog Bazar in the evening, leaving 16 people injured.
On information, police went to the spot, brought the situation under control, and took the injured to the Barguna General Hospital.
Sabuj died on his way to the hospital.
Abir Muhammad Hossain, officer-in-charge of Sadar Police Station, said they arrested 10 people over the incident as a case was filed in the night.