The officials believe that out of seven attackers, five militants blew themselves up inside the administration block and two others outside it, the paper said. Citing officials, Dawn said the attackers entered the building by climbing its rear wall, using a ladder and cutting barbed wire. They then stormed the main auditorium wher e an instructor was giving a first-aid lesson to senior students. "Did the attackers have prior knowledge of the congregation in the main hall... This is one of the questions we are trying to find an answer to," a security official said. The militants first shot dead a watchman standing at the rear of the auditorium.