QUETTA - At least three police personnel sustained injuries in hand grenade blast at Murbarak Chowk near Spiny Road Quetta on Monday evening. According to police sources, the police personnel were patrolling in a mobile van in the area when unknown men hurled a hand grenade. As a consequence, three police personnel received injuries. The injured were rushed to civil hospital for medical aid where one of the injured was referred to CMH in view of his critical condition. Two of the injured victims were identified as Muhammad Azhar and Shah Rukh. Police cordoned off the entire area and started search to trace out suspects.