In a final transaction before the US lifted long-standing sanctions on Iran, the two nations completed a high-profile prisoner swap Saturday. But one American who went missing in Iran more than eight years ago was not released. That man is former FBI agent Robert Levinson, whose family said in a weekend statement that they were "devastated." Iran has denied for years that it knew anything about Levinson's whereabouts, a claim that both US officials and his family have repeatedly rebutted. Levinson served more than two decades in the FBI, which has a $5 million reward out for information leading to his location, according to Reuters.