DERA GHAZI KHAN - Three persons were killed and 50 other injured when a passenger bus over here in Dera Ghazi Khan early Saturday morning.According to rescue sources, the ill-fated bus overturned near Turman Checkpost when it was on the way from Karachi to Dera Ghazi Khan, killing three passengers on the spot and left 50 other wounded. The injured were shifted to Tehsil headquarters Hospital Tonsa Sharif where some of the injured are said to be in critical condition.