Fringe elements of the underworld may be involved in the serial blasts that shook Mumbai on Wednesday night and claimed 19 lives, according to sources.
The Maharashtra Anti-Terrorism Squad has started questioning some elements of the underworld and their informers to garner more clues about the case.
"A turf war has been going on between the underworld and terror outfits for some time. We believe that the underworld may have carried out the blasts to step up the heat on these terror networks," said an official.
The key to the investigation would be the procurement of explosives that were used in the blasts.
Nearly 40 people with underworld links have been questioned about the blasts, along with operatives of the Indian Mujahideen, who are languishing in various jails across India.
No substantial leads have emerged from the ongoing investigations so far and even the CCTV footage obtained from OperaHouse, one of the blast sites, has not provided any clues. There have been no specific leads on the persons spotted conversing for a long time at the site just before the blast.