Delawar Hossain Sayedee, who was sentenced to prison until death for crimes committed against humanity in 1971, died on Monday.
He died at Bangabandhu Sheikh Mujib Medical University (BSMMU) in Dhaka at 8:40 pm.
SM Mustafa Zaman, professor of cardiology department at BSMMU, confirmed the matter to Prothom Alo.
Masud Sayedee, son of Delawar Hossain Sayedee, told Prothom Alo on Monday night that his father's health condition was better in the morning. Suddenly, his health condition deteriorated and he passed away at 8:40 pm.
Earlier, he suffered a heart attack inside jail on Sunday and was taken to Shaheed Tajuddin Ahmad Medical College Hospital in Gazipur from Kashimpur central jail on a prison ambulance.
Later, he was shifted to BSMMU for better treatment.
Jail sources said Sayedee has long been incarcerated at part-1 of Kashimpur central jail after he was sentenced to prison until death for crimes against humanity in 1971 Liberation War. He fell ill at around 5:00 pm Sunday.
Appellate Division of the Supreme Court on 17 February 2018 sentenced him to prison until death for crime against humanity.
He was arrested on 29 June 2010 in a case filed on charges of hurting religious sentiment. He was later shown arrested for crime against humanity on 2 August that year.