Dec. 9, 2011 -- A new "proof of life" video emerged Friday of former FBI agent Robert Levinson who disappeared in Iran in 2007, the first substantial piece of public evidence that he is alive and being held as a captive by an unknown group.
In the video, posted by his family on their website, Levinson appears gaunt, addresses "my beautiful, my loving, my loyal wife Christine," and says his diabetes medication is running out.
"I am not in very good health," says Levinson.
He does not name his captors but pleads for the United States to deal with them.
"I need the help of the United States government to answer the requests of the group that has held me for three and a half years," he said, wearing a thin shirt and sitting on the floor in front of a rock facing.
"Please help me get home. Thirty-three years of service to the United States deserves something. Please help me," Levinson said on the tape, his voice breaking.
Christine Levinson told ABC News that her husband's appearance on the tape made her sad. "He has probably lost 75 pounds," she said, "and the shirt he was wearing is actually the shirt he wore when he disappeared. But I was happy at the same time because it was Bob."
Levinson has seven children and two grandchildren, and this December will mark his fifth holiday season without his family.
"The frustration is that every day passes," said Christine Levinson, "and he's still not home with us, and I don't know how to get him home."
American officials thought Levinson was dead until the hostage video was sent to his wife via e-mail accounts in Pakistan and Afghanistan. The family reportedly received the tape last November but is making it public only now.
"It could be that he was captured without authorization and now the group that's holding him is kind of embarrassed by it but they haven't figured out a way yet to let it go," said Richard Clarke, a former White House counterterrorism official and now an ABC News consultant.
In a statement on the family website, Levinson's wife, Christine, and son, David, seek to send a message to the group holding the former FBI agent.
"We tried to contact you but you never responded," Levinson's son said.
"No one can help us but you," he said.
Levinson Disappeared in Iran in March 2007
Levinson disappeared in March 2007 on the Iranian island of Kish where he had gone as part of his work as a private investigator.
U.S. officials say Levinson was not operating in any way on behalf of the U.S. government or any of its agencies at the time of his disappearance.
Iran has repeatedly denied any knowledge of what happened to Levinson, despite the evidence he was last seen in Iran.
U.S. diplomats have repeatedly pressed Iranian officials about Levinson with little success.
A State Dept. spokeswoman said Friday it was the family's idea to release the tape, and that she was "hopeful" that the publicity would bring more leads.
"We have been sharing relevant information that we have about his case with many governments to see what we can do," said Victoria Nuland.
However, the State Dept. currently has no further leads on Levinson's whereabouts.
"We're not in a position to confirm even where he is," Nuland said.