Preliminary investigations into Sunday’s blast in Ludhiana indicate that RDX was used. Security agencies are also looking at the possibility of pro-Khalistan militant groups having carried out the attack in tandem with Pakistan-based groups like Jaish-e-Mohammed and Lashkar-e-Toiba.

Samples collected from the cinema hall have been sent for analysis and investigators are examining if there are links to the seizure of 3.5 kg of RDX in Ludhiana last month. The explosive was seized from a vehicle belonging to a former Punjab militant, and the trail had led to the Babbar Khalsa International, which has close links with Pakistan’s ISI.

Some pro-Khalistan groups also have links with Kashmiri militants.

The blast sparked off a blame game this morning, with the Centre maintaining that it looked like a security lapse on part of the state as an alert had already been sounded. As Punjab Chief Minister Parkash Singh Badal defended his police, by evening the Union Home Ministry conceded that the alert sent to Punjab was general and warned of strikes during the festive season but did not indicate a specific target or a particular militant group’s involvement.

With the long festival season kicking in, the Centre has decided to go in for a public awareness campaign to sensitise people to security threats, particularly in crowded public places. Multiplexes are also being advised to put in place targeted security systems using in-house mechanisms like private guards and surveillance equipment.