In this April 22, 2015 photo, Guillermina Sotelo, who is searching for her missing son, Cesar Ivan Gonzalez Sotelo, leads a group of relatives of missing persons as they look for clandestine graves in the dry brush on the outskirts of Iguala, Mexico. At least 292 people have been added to the list of missing from the Iguala area since the 43 students disappeared there on Sept. 26, 2014. (AP Photo/Dario Lopez-Mills)