Metropolitan Magistrate Mohammad Ahsan Habib gave the order after Hasnat Karim was presented in the court on completion of his eight-day police remand on Monday, reported Dhaka Tribune.
The court fixed August 24 for hearing a bail petition filed by Hasnat, former North South University teacher.
In Monday's report, Humayun Kabir, an inspector of the Counter Terrorism and Transnational Crime unit and the Investigating Officer, stated that Hasnat had given important information about the terror attack, which investigators were verifying, adding that he should be kept in jail until the investigation is completed.
Earlier on Tuesday, Masudur Rahman, Deputy Commissioner of Dhaka Metropolitan Police, told reporters at his office that police would not seek fresh remand for Hasnat for some time.
"The information we got from Hasnat during his two-term remand is being scrutinised," he said.
The law enforcers will seek remand for him in future, if necessary, Masudur added.
Hasnat was shown arrested on August 13 in the case linked with the killing of 22 hostages, including 18 foreigners and two policemen, in the terror attack at an upscale cafe in Dhaka.
Earlier on August 4, Hasnat and Canadian university student Tahmid Hasib among the survivors of the Gulshan attack were taken on remand for eight days.
Hasnat was again remanded for another eight days and Tahmid was sent to jail on Saturday after completion of his remand for 14 days in two phases.
