The Federal Investigation Agency (FIA) has submitted the preliminary investigation report pertaining to the attack on the Crime Investigation Department (CID) offices in Civil Lines in Karachi to the Interior Ministry. The report concluded that the blast that struck the CID offices on November 11 killing at least 17 people was a suicide bombing, sources said. The report further stated that the attack bore similarity to the one on the FIA building in Lahore. Moreover, 400-500 kilograms of TNT was used in the attack, sources quoted the report as saying.