"Of course if it becomes clear what his goal was, or if he was indeed on a mission, then perhaps specific assistance can be given," Ahmadinejad said. "For example, if he had plans to visit with a group or an individual or go to another country, he would be easier to trace in that instance."
In late 2010 and early 2011, Levinson's wife Christine received a proof-of-life video and photos that the U.S. hoped signaled Levinson's captors were willing to negotiate. U.S. and Iranian officials met several times in secret, but to no avail.
In March 2011, Secretary of State Hillary Clinton released a statement saying the U.S. had evidence that Levinson was being held "somewhere in southwest Asia." The implication was that Levinson might be in the hands of terrorist group or criminal organization somewhere in Pakistan or Afghanistan, not necessarily in Iran.
U.S. intelligence officials still believed Iran was behind Levinson's disappearance, but they hoped Clinton's statement would offer a plausible alternative story if Iran wanted to release him without acknowledging it ever held him.
Then, a surprising thing happened.
Nothing.
Nobody is sure why the contact stopped. Some believe that all Iran wanted was for the United States to tell the world that Levinson might not be in Iran after all. Others believe Levinson died.
Iran denies any knowledge of Levinson's whereabouts and says it's doing all it can.
"If any help there is that I can bring to bear, I would be happy to do so," Ahmadinejad said in an AP interview in September 2012.
In June this year, Iran elected Hassan Rouhani as president. He has struck a more moderate tone than his predecessor, sparking hope for warmer relations between Iran and the West. But Rouhani's statements on Levinson were consistent with Ahmadinejad's.
"He is an American who has disappeared," Rouhani told CNN in September. "We have no news of him. We do not know where he is."
At home in Florida, Christine Levinson works to keep her husband's name in the news pushing the Obama Administration to do more. Last year, the FBI offered a reward of $1 million for information leading to the return of her husband. But the money hasn't worked.
In their big, tight-knit family, Bob Levinson has missed many birthdays, weddings, anniversaries and grandchildren.
"There isn't any pressure on Iran to resolve this," his wife said in January, frustrated with what she said was a lack of attention by Washington. "It's been much too long."
