The incident was reported on Monday from a village in the district’s Gouripur Upazila, police said.
Quoting residents of Chorshirampur Village, police said four to five men, led by Akkas Ali and his son Kaiyum, were responsible for the death.
The victim, Shagar Ahmed, was about 17 years old from the same Upazila, said Gouripur police OC Delwar Ahmed.
On Monday morning, Ali, who owns a fish farm, his son and few others detained the victim over theft allegations, he said.
“They tied him to a post at the farm and began to beat him. After he lost consciousness, they dumped his body in the nearby woods. Police recovered the body the same day.”
The local Dauhakhola Union Parishad Chairman Shahidul Haque said he had seen photos of the assault on mobile phones of local residents.
“I have seen photos showing the teen in blood and tied to a post,”
The victim’s father Shipon Miah said his son collected and sold scrap.
He went out for work in the morning and never returned.
Police officer Ahmed said Akkas Ali and the other perpetrators have fled, but they were working to apprehend them.