Pictures of students from the Ayotzinapa Teacher Training College "Raul Isidro Burgos", who have been missing since last month's deadly clashes, are seen during a vigil at the Instituto Tecnologico Autonomo de Mexico (ITAM) in Mexico City October 14, 2014. On September 26, police allegedly linked to a criminal gang shot dead at least three students and abducted dozens of others during clashes in the southwestern city of Iguala. Forty-three of the students are still missing. REUTERS/Tomas Bravo (MEXICO - Tags: CIVIL UNREST CRIME LAW EDUCATION)