Chaki, 60, served as the cultural affairs secretary of the Pabna district unit of the Awami League, the political party formerly led by ex-prime minister Sheikh Hasina.

He was arrested on December 16 from his residence in Pabna town and was later shown arrested in connection with an explosion case linked to the August 4, 2024 violence during the July Uprising, which ultimately led to the removal of Sheikh Hasina from power.

Confirming the death, Pabna Jail Superintendent Md Omar Faruk told The Daily Star that Chaki had been suffering from multiple health complications, including diabetes and heart disease.

“He suffered a cardiac arrest and was first taken to Pabna General Hospital on Friday,” Faruk said. “As his condition deteriorated, he was later shifted to Rajshahi Medical College Hospital, where he died at around 9:00 pm.”

The jail superintendent said the body would be handed over to family members after the completion of legal formalities.

However, Chaki’s family has alleged negligence and inadequate medical care during his time in custody.

His son, Sony Chaki, told the newspaper that his father had been arrested despite not being named in any case at the time.

“He was later shown arrested in an explosives case related to the August 4 violence,” Sony said. “My father had been suffering from diabetes and heart disease for a long time. His condition worsened in jail, but the authorities did not officially inform us.”

“We rushed to the hospital after being informed by others, but he did not receive proper treatment, which led to his death,” he alleged.

Rejecting the allegations, Jail Superintendent Omar Faruk said Proloy Chaki was provided medication according to his medical records and was taken to hospital promptly once his condition became critical.