LAHORE - A 17-year-old boy, a student of matriculation, was gunned down while three others sustained severe bullet injuries when a rival family opened indiscriminate firing over petty dispute in Kahana police Area on Thursday. The deceased later identified as Zahid Ali, was resident of Saraij Village. Police investigators said a day before the incident, the children from both of the families quarrelled over petty issues. Police investigators however claimed that two groups - Ishaq and Mohammad Ali - argued over sanitation issues, which resulted in the murder. PS Kahna Station House Officer SI Zaheer Babar said that family of Ishaq exchanged harsh words with the family of M Ali over drainage problem, which infuriated Ali, who along with his accomplices entered the house of Ishaq and opened fires on his family. As a result, four people received severe bullet injuries. The SHO said investigations were underway and the police team was attempting to arrest the accused.