The intelligence agencies are suspecting the involvement of pro-Khalistani elements in the rocket-propelled grenade (RPG) attack at Punjab Police's intelligence wing headquarters in Mohali on Monday, the sources said.
The sources, quoting intelligence inputs, said that Babbar Khalsa terrorist Harvinder Singh Rinda could be the mastermind of the attack.
They also said that Rinda is believed to be hiding in Pakistan and trying to reactivate the the pro- Khalistani elements in Punjab for terrorist activities in the state.
Pakistan's Inter-Services Intelligence (ISI) has been using these Khalistani elements in various countries such as the US, Germany and Canada, the sources said.
According to the inputs provided by the Punjab Police, the RPG was identical to the ones used by the US army, and the agencies are suspecting that this might have been procured by the terror outfits in Pakistan from the Taliban.
"The US army had left RPGs in large numbers when they left Afghanistan last year and the Taliban sold them to Pakistan-supported terrorist organisations, " the sources said.
Officials in the security set up said that the use of RPG by terrorists is a matter of concern for the forces, adding that it needs to be ascertained how the RPG was smuggled into Punjab.
Recently, four Khalistani terrorists were arrested by the Haryana Police from a toll plaza near Karnal, who had revealed that Rinda was dropping drugs and weapons in Punjab using drones from Pakistan.
The Ministry of Information and Broadcasting has ordered blocking of apps, websites and social media accounts linked to the proscribed terror organisation 'Sikhs for Justice', which is trying hard to revive militancy in Punjab.