Kidnapped Former FBI Agent Seen In New 'Proof of Life' Video

This copy photograph of a paper printout obtained by The Associated Press shows Robert Levinson. (AP Photo)

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.

AP Photo

This copy photograph of a paper printout... View Full Size

AP Photo

This copy photograph of a paper printout obtained by The Associated Press shows Robert Levinson.

Ex- FBI Agent Pleads for Help in Hostage Video Watch Video

Nov. 11, 1979: Iran Hostage Crisis Watch Video

'Nightline' Archive: America Held Hostage Watch Video

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.