Three days after a grenade explosion outside the Punjab BJP office here triggered a bitter political slugfest in the state, the Chandigarh Police and the Counter Intelligence wing of the Punjab Police on Saturday cracked the case with the arrest of five persons, and the recovery of a hand grenade, a .30 Zigana pistol and 10 live cartridges from their possession.Chandigarh DGP Dr Sagar Preet Hooda and his Punjab counterpart Gaurav Yadav jointly announced that preliminary investigations had revealed that the attack was executed by a Pakistan ISI-backed module operating under the directions of foreign-based handlers located in Portugal and Germany.Those arrested have been identified as Balwinder Lal, alias Shami, of Majari village in Nawanshahr; Jasvir Singh, alias Jassi, of Bharapur village in Nawanshahr; Charanjit Singh, alias Channi, of Sujawalpur village in Nawanshahr; Rubal Chauhan of Thana village in Shimla, HP; and Mandeep, alias Abhijot Sharma, of Dhuri, Sangrur. Two key perpetrators — Gurtej Singh and Amanpreet Singh — are at large and joint police teams are conducting raids to apprehend them.The attack was carried out outside the BJP office in Sector 37 around 5 pm on April 1. No casualties were reported.Investigations revealed that the accused were part of a structured network involving multiple cutouts and sub-modules, said DGP Yadav.The accused had transported a consignment of hand grenades, arms and live cartridges, which was circulated through multiple operatives before being handed over to the final perpetrators. Acting on the directions of Portugal-based handler Baljot Singh, alias Jot, the accused coordinated the delivery and execution of the attack, said AIG State Special Operations Cell (SSOC), Mohali, Deepak Pareek.A case has been registered under Section 25(1)(B) of the Arms Act and Section 61(2) of the Bharatiya Nyaya Sanhita at the SSOC Police Station, Mohali. Further investigations are underway to uncover the network, trace the supply chain, and establish the backward and forward linkages of the module.The attack had set off a fierce political firestorm, with the BJP, AAP, Congress and SAD trading barbs. The BJP had blamed the AAP government’s law and order record in the state and demanded accountability, while the AAP hit back, accusing opposition parties of exploiting a security incident for political mileage.