Gulshan café attack mastermind Tamim Ahmed Chowdhury's identity has been confirmed through a DNA match with family members.

A DNA sample from Tamim's body matched that of his father Shafi Ahmed Chowdhury and a sibling staying in Canada, said Masudur Rahman, deputy commissioner (Media) of Dhaka Metropolitan Police (DMP) yesterday.

The DMP's counter terrorism unit had sent the samples to their Canadian counterpart and the results were sent to Dhaka recently. 

Identified first through a photograph taken earlier, Tamim was shot dead with his two accomplices in a police raid in Narayanganj on August 27. 

Investigators say he accompanied the five Gulshan attackers from their Bashundhara residence and left bidding them farewell just before the 12-hour siege began around 8:40pm on July 1.

Twenty hostages, including 17 foreigners, and two police officials were killed before an army-backed commando team killed the five.

Tamim took the Sholakia attackers near the largest Eid congregation on July 7 in a CNG-run auto-rickshaw, gave them a briefing and left the district, said police. He coordinated many countrywide secret attacks.

Born on July 25, 1986 in Windsor in Canada, Tamim resided for a long time in Calgary and used to mix with people who had joined IS and gone to Syria.

The threat he posed prompted religious leaders in Windsor to ask him around 2013 to not mix with youths at the mosques.

Amarnath Amarasingam, a fellow at the George Washington University's programme on extremism, first came to know about him in 2015 while investigating jihadis in Windsor.

He interviewed friends of a jihadi named Ahmad Waseem, also known as Abu Turab, who returned to Canada  after being injured in fighting in Syria. Tamim's name then appeared.

Tamim was thought to have left for Syria to become a terrorist. A friend of Waseem told Amarnath that Tamim, facing harassment from law enforcement agencies in Canada, had decided to move back to his ancestral home in Bangladesh.

Since then he had been recruiting youths, radicalising them and masterminding ruthless attacks, say police.