Dhaka: Police shown former private university teacher Hasnat Karim and Canadian student Tahmid Hasib Khan, two survivors of a deadly siege at a Gulshan café, arrested under section 54 on Wednesday night. ‘We can confirm that they were arrested under Section 54 of CrPC (criminal procedure),’ police spokesman A.K.M Shahidur Rahman, referring to a law under which police can detain someone for suspicion over any crime.

It has been known that police will seek 10-day police custody for interrogating the survivors, who were missing after being grilled by police over the attack.

Police will present Hasnat and Tahmid before Dhaka Metropolitan magistrate Nurunnahar Yasmin’s court on Thursday afternoon and will seek custody.

The court will conduct a hearing in this connection at about 3:00pm.

Militants killed 22 people, mostly foreigners, when they raided the upscale Holey Artisan restaurant on the night of 1 July, as Bangladesh reels from a series of gruesome killings by Islamists.

Army commandoes stormed the cafe the next morning, killing all five attackers and rescuing 13 people, including Karim, his wife and their two children, as well as Khan.

The Islamic State (IS) group claimed responsibility for the attack, but police blame home-grown extremist group Jamayetul Mujahideen Bangladesh (JMB).

Hasnat Karim and Tahmid were both inside the Holey Artisan cafe when gunmen raided the premises on the night of 1 July.

But neither man has been seen in public since the end of the siege when commandos stormed the cafe in Dhaka’s upmarket Gulshan neighbourhood on the morning of 2 July.

Their families have previously said that both Karim and Khan were being held by the security services, insisting there is no evidence to link them to the attackers and that they were no more than innocent bystanders.

Police earlier this week named a Canadian citizen called Tamim Chowdhury as the mastermind of the attack, offering a reward of up to $25,000 for any information leading to his arrest.