Investigators trying to string together bits of evidence in the serial low-intensity blasts in the city have hit a hurdle as some CCTV cameras at the explosion sites have been found to be non-functional.
The CCTV cameras installed at Dena Bank, McDonald’s and Bal Gandharva traffic square, near where the explosions occurred, have not yielded any clue so far and some of them were non-functional, sources in the investigative agencies said on condition of anonymity.
Sources said the Maharashtra ATS, city Crime Branch and the NIA are looking for clues from the two bicycles as two of the four coordinated blasts last night occurred in their front carriers.
Explosives were strapped on these bicycles which appear newly purchased and investigators are trying to locate the shop from where these were bought in order to nail the perpetrators.
As reports said a black sticky substance with ammonium nitrate was used in the explosions, forensic experts are also trying to ascertain the concentration of explosives in the devices to zero in on the likely group behind the blasts.
According to sources, different terror groups use varied concentration of explosives in their “signature bombs“.
Reports have said battery operated detonators with digital timers could have been used to trigger the blasts.
Dayanand Patil, the only person injured in the blast at Bal Gandharva Theatre square, is being questioned by the police as to how the explosive found its way into his carry bag.
Sources said Patil, who sustained minor injuries, was not being treated as a suspect in the case.
Patil, who hails from nearby Urali Kanchan village and used to commute daily to Pune for tailoring work, is in hospital where his statement is being recorded, they said.