Published : 06 Jul 2016, 10:12 PM
DMP counterterrorism unit chief Monirul Islam told reporters at his office on Wednesday.
“One of the militants spoke to someone outside in Bangla through a mobile phone that night. He informed (the person on the other end) about the killings,” Islam said, quoting a freed hostage.
He hoped the investigation would reveal whether the militant had called someone within the country or abroad.
On Friday evening, a group of youths carrying guns and explosives seized the cafe in Gulshan. They killed 22 people, including 17 foreigners and two policemen.
Security forces stormed the outlet on Saturday morning. The Army said six attackers were killed and another was captured alive. Police have filed a case naming the six dead attackers.
Middle East radical group Islamic State reportedly claimed credit for the attack, released photos of the hostages killed during the siege, and photos of five gunmen after the standoff ended.
The five attackers have been accused in the case, but police named Jama’atul Muhjahideen Bangladesh (JMB) as the group behind the carnage.
Islamic State on Wednesday also released a video in which three Bangla-speaking men threaten more attacks in Bangladesh.