The charge sheet in the case filed over the attack at Gulshan Holey Artisan café will be submitted by this month.
Chief of Counter Terrorism and Transnational Crime Unit (CTTC) Monirul Islam revealed the information on Sunday while talking to reporters at the DMP media centre in the city.
The police official also said a total of five accused in the case were already arrested and all of them gave confessional statement.
Some other militants involved in the attack died in different anti-militant drives, he said.
The militants launched the attack to draw the attention of Islamic State (IS) group and put the government in trouble, he added.
Twenty-two people -- nine Italians, seven Japanese, one Indian, one Bangladeshi-born American and two Bangladeshis -- were killed in the terror attack on the restaurant on July 1, 2016.