ISLAMABAD: Those behind the suicide attack in Karachi will not go unpunished, Interior Minister Aftab Ahmed Khan Sherpao told a news channel on Friday. "It is a very tragic incident in which Allama Hassan Turabi has been martyred," Sherpao said, adding that identification and checking of suicide bombers was a difficult task, but the administration and the law enforcement agencies had been alerted against such attacks. "We expect people to remain peaceful," Sherpao said.