With relations between the United States and Iran already strained over Tehran's nuclear program and the future of Iraq, now there's a new source of tension: the safety of American citizens being held in Iran.
In his 22 years with the FBI, Bob Levinson was known for solving mysteries. Now, he is one.
A private consultant, retired from the government, Levinson played with his grandson two months ago in Florida then left the U.S. for the island of Kish, a free-trade zone of Iran. After a night-time business meeting, he disappeared — two months ago today.
The Iranian government claims it knows nothing about it. Levinson's wife, Christine, was in Washington today, pressing the U.S. government to do more.
"He called every day," Christine says. "He e-mailed his children every day. And when I did not hear from him the next day, I knew there was something wrong."
"I do know that he was last seen in Iran," she says when asked if she's sure he's being held in Iran. "That's why I'm asking the Iranian government to help me find him, because I think that they have the resources we need to find him and bring him home."
Christine is hoping that anyone with any tips or ideas will use it to send her e-mails.
She has contacted Iran's ambassador to the United Nations for help. And two weeks ago, she wrote a letter to the Iranian president, Mahmoud Ahmadinejad.
"I asked him to help find Bob," she said.
She has heard no response.
Levinson's trip was on behalf of a tobacco company, which was eager to learn more about the problem of cigarette counterfeiting and smuggling in the Middle East. He went to Kish to meet with someone he hoped could help him develop more information.
He's not the only American the U.S. is worried about.
Haleh Esfandiari, a scholar and Iranian expert who lives in Washington, made regular trips to Iran to visit her ailing mother, most recently in December. But the Iranians wouldn't let her leave. They've questioned her repeatedly and on Tuesday threw her in a Tehran prison.
The Woodrow Wilson Center, where Esfandiari is director of the Middle East Program, says she was on her way to the airport in Tehran on December 30, when her taxi was stopped by three men who held her at knifepoint and stole her luggage and purse, including her passport.
When she applied for replacement travel documents, she was was questioned by the intelliegence ministry. Interrogation sessions, some lasting as long as eight hours, continued for six more weeks, finally culminating in her arrest.
Her husband, a college professor in Virginia, says she was a scholar, not a threat to Iran.
"The idea that you should be interrogated and then eventually jailed for organizing conferences is really a bit unbelievable," says Shaul Bakhash.
Middle Eastern experts say tension with the U.S. and internal politics in Iran complicate freeing the Americans.
"You have a small minority, especially in Tehran these days, that are simply absolutely dismissive of international public opinion and are ready to do their own thing at all costs," says Karim Sadjadpour, an Iranian expert.
For now, the United States says it's doing all it can, appealing to Iran through other countries.