At least six persons killed and five others were injured in incidents of violence in different areas of Karachi during last 12 hours. According to police, two robbers were killed in a police encounter in Orangi Town P&T Colony on Saturday morning and they were wanted in several cases, Pakistan Tribune reported.A Rangers’ officer was injured while resisting a robbery in Sohrab Goth area. Police the robbers targeted Rangers’ personnel on a bus stop and shoot him on arm upon resisting.In another incident a 55-year-old person was gunned down by anonymous assailants in Sabzi Mandi area near Ranchor Line.