An under-trial prisoner was declared dead after being brought to Dhaka Medical College Hospital (DMCH) on Saturday.
The deceased was identified as SM Mahasin-ul-Muluk, 68, son of Barkat Ullah.
Inspector Bachhu Mia, in-charge of DMCH police camp, said Muluk was brought to the DMCH around 5:30 am from Keraniganj Central jail as he fell ill.
The on-duty doctor declared him dead after his arrival in the emergency department of the hospital, he said.
The body was sent to the DMCH morgue.