KARACHI - A police constable of the PIB Colony police station was suspended and arrested over allegedly killing a general secretary of Pakhtoon Student Federation on Wednesday.A PSF leader Asmat Ali, 25, was killed outside his residence in Micasa Apartment situated near Hassan Square within PIB Colony police station. PSF leaders complaint that the PIB Colony’s police constable, namely Mirza Hussain Baig, deputed at the Chase departmental store killed their fellow after an exchanged of hot words over unknown reason.The deceased hailed from Swat and lived here in a city at Micasa apartment situated near Hassan Square and was the student of BBA. PSF leaders further said that the police constable later tried to change the nature of the incident saying that deceased accompanied by another activist, namely Faisal arrived at the departmental store for collection of extortion money. Faisal was in the custody of the Rangers.