WASHINGTON – Elite Mexican commandos, trained by U.S. forces to combat the drug cartels have switched sides and are working for the drug smugglers in the border area posing a special hazard to American law enforcement and Border Patrol agents, according to a U.S. Justice Department memo. The commandos, trained by the U.S. Army at Fort Benning, Georgia, are known as "Los Zetas.". The Justice Department warning was sent to law enforcement agencies throughout the Southwest.. Using the commando training, Los Zetas are known to be extremely violent and have been blamed for an outbreak of violence along the Mexican...