A war crime accused from Bagerhat died at Dhaka Medical College Hospital (DMCH) on Monday.
The deceased is Md Abdul Ali Mollah, 80.
Dhaka Central Jail prison guard Md Zakaria said the doctors pronounced Abdul dead around 9:30am on Monday.
He said Abdul had been taken to the hospital after he fell sick at the prison in the morning.
Confirming the matter, DMCH outpost Sub-Inspector Bachchu said the body was kept in the morgue for autopsy.