A 65-year-old prisoner of Dhaka Central Jail died at Dhaka Medical College (DMCH) Hospital on Monday.
Prisoner Azhar Ali died around 6 pm.
He was admitted to DMCH on April 12.
DMCH Police Outpost Assistant Sub-inspector (ASI) Md Masud Mia, said the body has been kept in the hospital morgue for an autopsy.
It could not be known immediately what case he was arrested for.