DERA ISMAIL KHAN: Unidentified motorcyclists gunned down an ex-policeman here on Thursday, sources said. The incident took place in the jurisdiction of Cantonment Police Station near Dinpur, a dense locality of the city. The sources said the gunmen riding motor-bike sprayed Muhammad Arshad with bullets, leaving him critically injured. They added that Muhammad Arshad sustained fatal head wounds and succumbed to his injuries.