The deceased was identified as Mamun, 22, son of Sadequl Islam of Harinmari-Khatpara village in the upazila.
The police recovered the body of Mamun from a river on Monday morning.
Akalu Donga, chairman of Amjankhor union, said a group of Bangladeshi people, numbering 7-8 went to the main pillar no 382 along the bordering area for bringing cattle on Saturday night.
Later, the BSF members caught Mamun while they were returning home .
The BSF members beat up Mamun mercilessly, leaving him dead and then threw the body into Nagor river.
Habibul Haque Prodhan, officer-in-charge of Baliadangi Police Station, said police recovered the body and sent it to the local hospital morgue.