Quetta: 2 sons were killed and their father was injured in firing incident in Quetta. The firing incident took place near Gahi Khan Chowk on Saryab road Quetta. Property dispute is stated to be cause of the incident. According to police One Muhammad Afzal resident of Bypass was on his way to Session court Saryab along with his two sons. About three armed persons opened fire on their vehicle near Gahi Khan chowk.Both the sons died on the spot due to firing while Muhammad Afzal was shifted to hospital in injured condition. The culprits are stated to be cousins of victims who fled the scene. According to police further investigation into incident is underway.