KARACHI The Special Investigation Unit (SIU) of the Sindh Police have arrested three former students of Karachi University involved in fixing explosive device at the main cafeteria of Karachi University on December 28. The suspects included Mohammad Omer alias Chohta, son of Mohammad Aslam, Hafeezullah alias Bilal, son of Naimatullah Khan, and Syed Faiz Ali, son of Syed Musaddiq Ali Shah. The accused persons were said to be the former university students were running their own group with the title of 'Punjabi Mujahideen, said SIU SSP Raja Omer Khattab and added that the arrests were made after a brief encounter, took place on Maripur Road. Police also seized two hand grenades, one kalashnikov, two repeaters, two TT pistols and a pick-up from their possession.