"Right now, there is nothing concrete we can say that we have. We are following certain leads. We are going forward. But definitely the investigation is moving in a positive direction," Hyderabad city police commissioner Anurag Sharma told PTI.
"All I can say that we are doing our best efforts and giving a time frame at this moment is not possible," he added.
Meanwhile, an expert who participated in the forensic analysis of the blast material said the main component of the explosives is Ammonium Nitrate.
On February 21, Hyderabad was rocked by two blasts in the crowded Dilsukhnagar area killing 16 persons and leaving 117 injured. The blasts triggered by Improvised Explosive Devices (IED) took place outside a roadside eatery near Konark and Venkatadiri theatres in the area.
"We cannot establish the pattern though the similar compound was found in Lumbini Park and Gokul Chat Bhandar blasts earlier in 2007. It is too early to come to a conclusion," the expert said.