Diplomat and former US Ambassador Manuel Rocha is facing charges related to secretly serving as an agent of Cuba's government.Rocha is the latest in a long line of spies, who have worked for the federal government while spying for other countries. Some for decades at a time.NPR's Mary Louise Kelly talks to former CIA officer Robert Baer about the charges against Rocha and how he might have managed to go undetected for four decades.Email us at considerthis@npr.org