Dhaka Metropolitan Magistrate Snigdha Rani Chakrabarty gave the order to the investigation officer of the case.
Gulshan police initiated the case under the Anti-Terrorism Act naming six and several unidentified others on Monday midnight.
According to police, five terrorists, identified and killed by army commandos in their bid to rescue the hostages after a 12-hour-long stand-off, were among the six named, bdnews24 reported.
Home Minister Asaduzzaman Khan Kamal yesterday confirmed that five of the persons killed in the "Operation Thunderbolt" are militants.