The police said they were now trying to arrest the suppliers of the weapons and have sought "help of the general people".
"We have been able to trace the source of the weapons. We are trying to arrest those who supplied the weapons," Inspector General of Police AKM Shahidul Haque told reporters.
"The arms used in the attacks were not very modern. We have found the source from where the attackers got them arms. The mastermind of the attacks have been identified and they are under surveillance," Haque was quoted as saying by the 'Dhaka Tribune'.
He said the police were trying to combat militancy by awareness and prevention and needed "help of the general people" in bringing the masterminds of the 12-hour-long carnage to book.
"We are preparing a list of missing people. It would be published after verification," Haque said.
Educational institutions of the country are under surveillance as the militants identified behind some recent attacks including that at Holey Artisan were students, Haque said, adding that they are yet to ascertain any "concrete" international link into the attack.
Twenty two people, mostly foreigners including an Indian girl, were killed by suspected ISIS militants inside a cafe popular with expats in the diplomatic zone in Dhaka in the worst terror attack in Bangladesh before commandos launched an assault, killing six attackers and capturing one alive.
Around 30 people were injured in the attack for which dreaded ISIS claimed responsibility through its Amaq news agency, nearly four hours after the hostage crisis unfolded.
The government, however, maintains that the home grown militant outfit Jamaat-ul-Mujahideen (JMB) was behind the attack.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)
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