The family of former FBI agent Robert Levinson, who was taken hostage in Iran in 2007 and not listed among the prisoners being freed by the Iranian government on Saturday, said they are "devastated" that he will not be coming home with the others."We are happy for the other families," Levinson's Coral Springs, Florida relatives said in a statement, reports Miami's CBS affiliate. "But once again Bob Levinson has been left behind. We are devastated.”Levinson, a retired FBI and DEA agent, who had 28 years of service with the U.S. government, went missing on Kish Island, Iran, in March 2007, and in 2014, his wife confirmed that he had been working as a consultant for the CIA. He reportedly was also investigating cigarette smuggling in Iran as a private detective. His family has not had direct contact with him since he disappeared, but in 2010, his wife received photos, a video tape, and documents detailing his detention from an anonymous source.The FBI has offered a $5 million reward for his return. On Saturday, the other prisoners, all Iranian-Americans, were ordered released in a prisoner swap. Those prisoners include Washington Post journalist Jason Rezaian, Marine veteran Amir Hekmati, Christian pastor Saeed Abedini, and another prisoner, Nosratollah Khosrawi.Last month, Levinson's son, Daniel, wrote an op-ed piece for The Washington Post, urging caution for Westerners planning visits to Iran after the United States and other nations came to their agreement on Iran's nuclear capabilities."My family has always advocated maintaining an open line of communication between Washington and Tehran, as we believe it can pave the way to improved relations and progress on key issues," Levinson said in the piece."We saw the nuclear talks as a golden opportunity to resolve my father’s case, so long as both sides were willing to negotiate. However, we were devastated that he was not released in the aftermath of the accord. Now we fear that the United States has squandered its best opportunity for leverage in ensuring my father’s safe return home."