"A number of people have been questioned so far but the exact figure we cannot tell you. Among those questioned include two IM members, who were recently arrested, people having links with underworld gangs and other anti-social elements in the city. We believe we are moving in a right direction," an ATS official said.
Officials of the ATS and crime branch have also activated their human intelligence networks as they sought maximum help from their informers across the state.
"We have a reason to believe that the terror suspects may not have used that much technology to execute the blasts. So we are almost now depending upon human intelligence and whatever information we are getting from the informers we are immediately verifying it to get some clues," he added.
Recently, Maharashtra ATS arrested two alleged Indian Mujahidden members identified as Mohammed Mobin Khan (32) and his cousin Ayub Raja Shaikh (28) from suburban Mankhurd with firearms.
The suspected IM operatives had allegedly provided vehicles that were used in 2008 serial blasts in Gujarat in which 56 people were killed and over 200 were injured.
The triple blasts at Zaveri Bazar, Opera House and Dadar on Wednesday here claimed 18 lives and left more than 130 people injured.