 Cadereyta Jiménez, a city in northeast Mexico near Monterey, is home to one of northern Mexico’s biggest oil refineries and it is controlled by the Los Zetas drug cartel.Over thirty eight oil workers for the state oil company PEMEX have disappeared and the area is known for mass graves.The flow of drugs and contraband are controlled primarily by Los Zetas, a paramilitary group that once worked for the Gulf Cartel before becoming an independent criminal organization.