Investigators in Pune's terror attack are increasingly veering to the view that the Indian Mujahideen (IM) was behind the bombing because the city - an IT and educational hub popular also with foreigners - was once used by the group as its "important base and recruiting ground", said an official privy to the probe.
Sleuths of Maharashtra's Anti-Terrorist Squad (ATS) scouring for clues into the deadly blast that killed nine people are also closely monitoring CCTV footage from near the site that shows images of two potential suspects entering the German Bakery where the bombing took place.
The arrested members of the IM, a home-grown Islamist terror outfit with suspected links to the Pakistan-based Lashkar-e-Taeba (LeT), are being interrogated again in connection with the Pune blast.
They include a recently arrested operative Shahzad Ahmed, alias Pappu, whose arrest February 2 in Azamgarh in Uttar Pradesh had caused a major dent in the organisation - believed to be an offshoot of the banned Students' Islamic Movement of India (SIMI). Security agencies say local IM members have been trained in arms and explosive handling in Pakistan and Bangladesh.
Ahmed was believed to have been trained as a pilot for a possible 9/11-type attack.
"From the preliminary examination, it (the blast) appears to be the handiwork of the IM," said the official said, on condition of anonymity.
"The IM had used Pune as one of its important bases and the city was on its radar for sometime," the official told IANS.
The group first came into the limelight after it owned up to the wave of bombings in Jaipur, Bangalore, Ahmedabad and New Delhi in 2007 and 2008.
Iqbal and Riyaz Bhatkal, the two brothers presently hiding in Karachi in a LeT camp and considered top leaders of the outfit, were in Pune for sometime in 2006 when they set up a terror module in the city that has a large number of Indian and foreign students studying such diverse subjects as management, media, engineering, films, software development, etc.
With the Bhatkal brothers in Karachi are two other IM leaders, Mufti Sufiyan and Rasool Parti, according to intelligence sources.
Iqbal, a hardcore Islamist, was part of the Tableeghi Jamaat - an organisation of "puritanic Muslims" - and used to preach in the Pune Jamia Masjid and other mosques in the city.
"Under the garb of the Tableeghi Jamaat the Bhatkals did talent hunting for the Indian Mujahideen in the city," the official said.
The brothers met Mansoor Peerbhoy, a software professional, in Pune in 2007 through a common friend Asif Bashir Sheikh, another IM operative. Peerbhoy, accused in the 2008 blasts in various Indian cities and in police custody, was recruited in the IM soon and tasked to look after its IT cell.
According to sources, Peerbhoy, who has revealed his rendezvous with the Bhatkals in his interrogation, and his colleague Sheikh are being questioned afresh for clues into Saturday's bombing.
The two used to stay in a rented accommodation in Kondava in Pune before shifting to Mangalore in August 2008.
Besides, Sheikh and Peerbhoy other members of the IM's Pune base were Mubeen Qadir Sheikh, Akbar Chaudhary, Aniq Syed, Abdus Subhan Qureshi and Mohsin Chaudhary. Except for Chaudhary and Qureshi all its Pune members have been arrested.
Intelligence agencies believe that Qureshi and Chaudhary could have been behind the German Bakery bombing. They have have launched a massive manhunt to arrest the two who "have not fled the country", said the sources.
Intelligence agencies that collected evidence from the blast said the materials used, RDX and ammonium nitrate, in the blast and the pattern of the bombing point towards the IM's modus operandi.