Four low intensity blasts in the heart of Pune, a thickly populated area with shopping complexes, eateries, a garden and famous theatre, has thrown open a wide debate on who could have been the brain behind the incidents.
One bomb which was placed in a cake was defused, said police sources.
Apart from local police officials, and Bomb Detection and Disposal Squad (BDDS), a team of ATS officials had reached the spot.
Police sources said that two teams of the National Investigation Agency (NIA) one each from Mumbai and Delhi were on the way to the spot.
Bombs that exploded were planted in dustbin outside McDonalds at Jungali Maharaj Road and on bicycles outside Dena Bank and Garware chowk. Two other bombs were placed in a dustbin outside Bal Gandharva Theatre on Jungali Maharaj Road.
Statement of Dayanand Patil, who was injured in the blast and was treated at Sasoon Hospital, is being recorded, said police sources.
ATS and NIA officials did not rule out the possibility of groups like Indian Mujahideen (IM) or of the likes of right wing organizations like Sanathan Sanstha.
A senior police officer, requesting anonymity said, "Both the groups have conducted low intensity blasts in the past at Uttar Pradesh, Delhi, Bangalore and Goa. One bomb has been defused, and we would be able opine only after forensic experts give their opinions."
In May 2011, a low intensity blast had been triggered outside the Delhi high court which was suspected to be the handiwork of Indian Mujahideen. Later a major blast outside the Delhi high court in September 2011 had killed 11 and injured 70 others.
Investigations and arrests into the blast had revealed Indian Mujahideen's hand in the low intensity blast.
Also, Indian Mujahideen had conducted a series of low intensity blasts in Bangalore in 2008.
A series of low intensity blasts were planned and executed by Indian Mujahideen cadre in Uttar Pradesh in 2006. Four of the bombs planted in Uttar Pradesh had not exploded.
The suspicion looms around Indian Mujahideen considering David Headley, a Lashkar-e-Taiba (LeT) operative arrested for his involvement in the Mumbai 26/11 terror attack, had visited Pune and conducted reconnaissance in the city.
Also, arrests of Himayat Baig accused in the Pune German Bakery blasts had told investigators of possible targets in Pune.
Also, when the Mumbai crime branch had arrested 21 Indian Mujahideen operatives in September 2008 it had come to light that Kondwa, an area in Pune, was being used as their primary base to recruit youth from Pune.
At the same time, investigators are not ruling out the possibility of right wing terrorist groups.
Two persons owing allegiance to Sanathan Sanstha - a group responsible for conducting blasts outside a theatre in Thane in June 2008 - were arrested for their alleged role in Margoa in October 2009.
The blast had occurred at around 9.45pm near Grace Church in Margao, at a time when effigies of Narkasur, a mythical demon, were being burnt to celebrate the victory of good over evil on the eve of Diwali.
Previous blast in Pune
February 13, 2010: A bomb placed outside German Bakery at Koregaon Park had exploded killing 17 persons and injuring 64. The Anti-Terrorism Squad had arrested Mirza Himayat Baig, an IM operative. The ATS has also filed charge sheet against Baig and six others absconding accused.