The Punjab Police Thursday uncovered the involvement of a narco-terror module linked to the Pakistan-backed Babbar Khalsa International (BKI) terror network in the Nalagarh Police Station blast in Himachal Pradesh, a senior officer said, adding two operatives have been arrested. Director General of Police (DGP) Punjab Gaurav Yadav said that the operation was conducted in close coordination with Himachal Pradesh Police and central intelligence agencies. Those arrested have been identified as Shamsher Singh, alias Sheru alias Kamal, and Pardeep Singh, alias Deepu, both residents of Rahon in SBS Nagar. Yadav said that arrested operatives were acting on the directions of Shushant Chopra, a close associate of Gurpreet, alias Gopi Nawanshahria, and BKI mastermind Harwinder Singh Rinda. Police teams have also identified the two accomplices of the arrested accused persons and raids are being carried out to nab them, he said.