"NorthSouthUniversity's acting pro-VC Gias Uddin Ahsan was arrested on Saturday for renting out a flat to the attackers of Holey Artisan Bakery," said Masudur Rahman, deputy commissioner of Dhaka metropolitan police.
Ahsan is the dean of NSU's School of Health and Life Sciences, according to the private university’s website. Ahsan's nephew Alam Chowdhury and Mahbubur Rahman Tuhin, the manager of a house in Bashundhara Residential area were also arrested.
He said five militants who carried out the attack on the cafe on July 1 had taken shelter in the flat owned by Ahsan. The police official said the other associates of the attackers fled the flat after the attack. Several cartons were seized from the flat.
The police suspect the cartons were used to keep the grenades used in the attack that left at least 20 hostages, including an Indian, and two policemen dead. Security forces killed six persons in the raid at the cafe to free hostages.
Islamic State claimed responsibility for the attack, though authorities have dismissed the claim. One of the militants killed by the police was a student of NSU. His family said he had been missing for months.
Ahsan's nephew Alam and manager Tuhin were tasked with renting the flat.
"But they did not follow the DMP instruction to collect tenants' info while renting the flat," Rahman said. He said police's counterterrorism unit, which is investigating the attack, arrested the trio.
The unit's Deputy Commissioner Saiful Islam told bdnews24.com a person rented the flat in May. They suspect he is a member of Jama'atul Mujahideen Bangladesh.
Meanwhile, reports said Hasanat Reza Karim, who was a teacher of the NSU, was alo among the hostages. He was sacked reportedly for his links to banned Islamist organisation Hizb-ut Tahrir.
His family has alleged that the police did not release him with the other hostages and he has been unaccounted for since then. After the Gulshan attack, police released a list of 10 youths missing for months, suspecting their links to terrorism.
Two of them -- Mohammad Basharuzzaman from Rajshahi and Junnun Shikder from Jigatola in Dhaka -- were also students of NSU. One of the attackers involved in a second attack on Bangladesh's largest prayer congregation has also been identified as NSU student Abir Rahman.
The university came under scrutiny after the killing of blogger and Ganajagaran Mancha activist Ahmed Rajib Haider in 2013. All the persons arrested in connection with his murder were students of the Electronics and Electrical Engineering at the university.