Protesters set a police van and two buses on fire after the killing of an activist of Muttahida Qaumi Movement (MQM) in Karachi. As per details, an activist of Muttahida Qaumi Movement was on the way to Pir Ilahi Buksh (PIB) colony, when some unidentified persons opened fire, killing him on the spot, Pakistan\'s (Dunya) News reported. After the incident, protests have been started in different areas and angry mob also torched many vehicles including a police van. The coordination committee of MQM has announced mourning over the killing. At least two people including a woman have also been injured in another firing incident in (PIB) colony.