Bangladeshi police have said that they might have shot dead a hostage by mistake during the Dhaka café siege on 1 July. The revelation comes as police continue to search for accomplices of the gunmen who killed 20 people at the Holey Artisan café.

The Islamic State (Isis) terrorist group claimed responsibility for the attack and posted an image of five young men clutching guns on their website hours after the incident. However, authorities have dismissed the link to Isis and insisted that Jamaeytul Mujahdeen Bangaldesh (JMB), a local banned militant group, was behind the terrorist attack.

Saiful Islam, a top police official investigating the attack, told Reuters: "We killed six people in the restaurant. A case has been registered against five. The sixth man was a restaurant employee. He may not be involved."

The restaurant employee has been named as Saiful Islam Chowkidar, a pizza maker at the Holey Artisan. A co-worker confirmed that it was him and told Reuters that Chowkidar had worked there for 18 months.

Bangladeshi police have now named five men as attackers in a case filed on 5 July. The case will allow them to launch an official investigation into the incident, which will include questioning family members of the militants for clues about their radicalisation.

Apart from the five terrorists shot dead, two suspects remain in hospital and police are searching for six members of JMB who are suspected of orchestrating the attack. The country has been shocked by the nature of the attackers after it was revealed that many of them were well educated and from wealthy families.

One of the attackers has been identified as the son of Imitaz Khan Babul, a politician from Bangladesh's ruling party, the Awami League. Babul has spoken of his shock at seeing his son's face among the images of attackers, adding that he had no idea that his son had been radicalised.