An Islami Chhatra Shibir leader, who was arrested in Prof AFM Rezaul Karim Siddiquee murder case, died while undergoing treatment at a hospital in Rajshahi yesterday.

Hafizur Rahman died after having a cardiac arrest at Rajshahi Medical College Hospital around 4:30pm, RMCH Deputy Director Gazi Saiful Alam Chowdhury told The Daily Star.

Rajshahi City Ward-19 Shibir General Secretary Hafizur, also a second-year student at Rajshahi University's Public Administration department, had sickle cell anemia, according to the doctor.

Anemia is a condition marked by a deficiency of red blood cells or hemoglobin in the blood. Sickle cell anemia is a severe hereditary form of anemia, he added.

Hafizur's brother Habibur Rahman said the Shibir leader had long been on medication as he had anemia since birth. “We used to give him [Hafizur] medicines in time. I am not sure whether he got that in jail.”

Their mother Halima Begum alleged that her son had been tortured in police custody.

However, Rajshahi Metropolitan Police (RMP) Commissioner Md Shamsuddin rejected outright the allegation.

Hafizur was arrested a day into the murder of Prof Rezaul of RU English Department in Shalbagan area of Rajshahi city on April 23. The teacher was killed in an attack that bore the hallmark of the previous murders of bloggers in the country.

The Shibir leader was placed on a four-day remand and sent to Rajshahi Central Jail on its completion.

Days later, he was admitted to the jail hospital and was shifted to the RMCH on May 17 on doctors' recommendations, said Shafiqul Islam Khan, senior superintendent at the jail.

Hafizur's body was handed over to his family after its autopsy at the RMC morgue.

On May 17, RMP Commissioner Md Shamsuddin said four operatives of banned militant outfit Jama'atul Mujahideen Bangladesh (JMB) took part in the killing of Prof Rezaul.

Of the four, Maskawat Hasan alias Sakib alias Abdullah was arrested in Gaibandha. The three other killers who were directly involved in the attack were yet to be arrested, he said at a press conference at the RMP headquarters.

Police had earlier arrested three more people, including Hafizur, in connection with the case. The other two -- Raihan Ali, imam of Prof Rezaul's village (Dorgamaria) mosque, and another Shibir leader Khairul Islam -- are behind bars.