DHAKA • The head of a Bangladeshi Islamist group accused of staging a deadly siege at a cafe died while trying to evade arrest earlier this month, said security officials.

Abdur Rahman died in hospital on Oct 8 after having jumped from the fifth floor of a building on the outskirts of Dhaka during a raid by the Rapid Action Battalion (RAB), an elite security unit.

The identity of Rahman, who headed Jamayetul Mujahideen Bangladesh (JMB), was confirmed through his possessions and by his family, who were shown pictures of his body, RAB said in a statement yesterday.

Several documents, letters and e-mail messages later retrieved by RAB "all proved that Abdur Rahman was the emir (head) of the new JMB", the statement added.

The authorities insist JMB was behind a siege at an upmarket cafe in Dhaka on July 1, in which 20 mostly foreign hostages were killed, even though the Islamic State in Iraq and Syria (ISIS) claimed responsibility.

RAB said some documents had been signed by Rahman using the alias Sheikh Abu Ibrahim al Hanif.

The statement made no mention of ISIS, but the April issue of Dabiq, a magazine affiliated with the organisation, reported that Shaykh Abu Ibrahim Al Hanif was the militants' "emir" in Bangladesh.

A RAB spokesman refused to comment on whether the two were the same man.

Tasked with tackling militancy and serious crimes, RAB has listed 19 attacks carried out by JMB, including the fatal shootings of an Italian aid worker and a Japanese national last year and a series of murders of religious minorities.

The cafe siege was by far the deadliest attack and stoked fears over the growth of Islamist extremism in a country where more than 90 per cent of the population are Muslims.

AGENCE FRANCE-PRESSE