lives nearly 10 hours away by bus, came here the day after the attack, when he found out his son cesar manuel, was among the missing students. the last time mario spoke to his son was the day of the attack. students told us that they were preparing to travel to mexico city that day 3...to commemorate the killings of students by the army and police in 1968, something done annually. david said he was among the students headed to iguala that night, where they hoped to find more buses to get to mexico city. in this video from that night, filmed by a student on his cell phone, the students are surrounded on either side, unable to escape. an ambulance arrives at one point - but is not allowed in. omar says he and other students then drove to iguala to find out what happened and help their friends. by the time they arrived, the police had left - and the attack seemed to be over. by the time the shooting was over, six civilians were dead including three students - and 43 others were missing. >> with the exception of one student - alexander mora - neither the students nor their remains have been found