Amritsar, Aug. 26 -- Punjab Police have solved the August 20 grenade attack at Jatta village under the Ramdas police station in Amritsar rural district, arresting three persons, including the mother of Harpreet Singh, alias Happy Passia, gangster-turned-terrorist linked to the proscribed group Babbar Khalsa International (BKI) and Pakistan's ISI, officials said on Tuesday. Addressing a press conference in Amritsar, border range deputy inspector general (DIG) Harmanbir Singh Gill said the investigation established that the attack was allegedly carried out as an act of revenge following a dispute linked to the recent village panchayat elections. According to the police, two motorcycle-borne assailants hurled grenades at the residence of Daljit Singh, a local resident with a criminal background, around 8.30pm on August 20. Following the attack, police registered a first information report (FIR) at Ramdas police station. Police said Passia opposed the present village panchayat during the recent elections. Tensions intensified on August 18 when four residents of Jatta village - Gurpinder Singh, Parminder Singh, Daljit Singh and Jobanjit Singh - allegedly fired shots in the air outside Passia's family residence during a local fair in Pashia village. A separate case was registered in connection with the firing. Jobanpreet was arrested on August 22 in that case. The firing incident prompted Passia's mother, Bhupinder Kaur, and his sister, Kirandeep Kaur, to allegedly plan retaliation. Investigators further alleged that Passia coordinated the attack from abroad with his Singapore-based associate Manpreet Singh, alias Sandy, who in turn allegedly worked with local operatives to execute the grenade attack. The three persons arrested in the case have been identified as Bhupinder Kaur, 60, of Passia; Jagroop Singh, 20, of Ghazi Nangal village; and Vishavpreet Singh, 18, of Ali Nangal village....