The Amritsar Rural Police on Tuesday claimed to have cracked the August 20 grenade attack on a house in Jatta village, tracing the alleged conspiracy to a dispute that arose during the recent Panchayat elections.Three persons, including the 60-year-old mother of US-based gangster Harpreet Singh alias Happy Passia, have been arrested, while two others have been nominated in the case.DIG Border Range Harmanbir Singh Gill said two motorcycle-borne persons had allegedly hurled grenades at the residence of Daljit Singh, who has a criminal background, at around 8.30 pm on August 20. There were no casualties, though three persons, including two women, were injured in the incident.The investigation allegedly revealed the involvement of Happy Passia, his family members and associates based abroad.Police said the attack was allegedly planned as retaliation for an incident on August 18, when four residents of Jatta — Gurpinder Singh, Parminder Singh, Daljit Singh and Jobanjit Singh — allegedly fired shots in the air outside the house of Happy Passia during a fair at village Pashia.A separate case was registered in connection with the firing, and accused Jobanpreet Singh was arrested on August 22.Investigators suspect that the firing triggered the chain of events leading to the grenade attack. Police alleged that Happy Passia coordinated with his Singapore-based associate Manpreet Singh alias Sandy and other associates to plan the attack.His mother, Bhupinder Kaur, and sister, Kirandeep Kaur, were allegedly involved in seeking revenge for the firing.The police have arrested Jagroop Singh, 20, of Ghazi Nangal, and Vishavpreet Singh, 18, of Ali Nangal, in the case. Earlier, they had arrested Bhupinder Kaur, 60, the mother of Passia. Bhupinder Kaur already faces a case under the Explosives Act registered at Ajnala police station.Manpreet Singh alias Sandy, who is presently in Singapore, and Passia’s sister Kirandeep Kaur have been nominated in the case but are yet to be arrested.The case assumes significance as it points to the alleged use of a foreign-based gangster network to settle a local political rivalry following the Panchayat elections. Police said further investigation is underway to establish the complete conspiracy, identify the role of other associates and ascertain how the grenades were procured.