New details are emerging about an American Navy veteran being held captive in Iran. The family of Michael White revealed this week that he's been in captivity since last summer and his mother said she has no idea about any possible charges against him.



White is the fourth American known to be held by Iran, and while CBS News has learned that Iran floated the idea of a prisoner exchange last year, State Department officials will not say whether the Trump administration is willing to negotiate. Contact between the two countries was cut off after President Trump exited the nuclear deal in May.

Sources tell CBS News that Iran is holding the Americans to try to extract concessions such as those received in a deal reached with President Obama. While the Trump administration offered to discuss prisoners last year, a senior administrative official said Iran turned that offer down, leaving the fate of the Americans unclear.

According to his family, the California native had traveled to Iran three times to visit an Iranian woman believed to be his girlfriend. After White didn't board his flight home from Iran in July, the 46-year-old's mother filed a missing persons report. About five months later, the State Department informed her that he is being held in an Iranian prison.

"I'm very worried about his health," she said. "He just got over cancer and I'm worried about his condition. It's very scary to me."

CBS News' Roxana Saberi spoke to Ivar Farhadi, a cyberactivist and former Iranian prisoner who met White while in Vakilabad Prison in the city of Mashhad in October and broke the news of his arrest on Twitter about three weeks ago.

According to Farhadi, White was suffering psychologically and was being held in a ward with dangerous criminals. Asked if White had been physically tortured, Farhadi said he couldn't discuss that subject with White because they were being watched. He said White told him he had not yet been charged, describing him as a "hostage."

Farhadi said that White told him he was arrested at Hasheminejad International Airport in Mashhad as he was preparing to fly to Turkey with his girlfriend to get married. As for why it took so long for White's family to know where he was, Farhadi said it's very likely that Iranian authorities threatened White's girlfriend to keep quiet. He added that White told him he was not allowed to make phone calls and had no access to a lawyer.

Since he went public about White on Dec. 18, Farhadi said Iranian authorities have been threatening to harm him in retaliation.

President Trump's hardline stance – exiting the nuclear deal and sanctioning Iran – has not stopped it from continuing to detain three other Americans, including Siamak Namazi and his 82-year-old father.

Iran's foreign minister told CBS News last April that Iran is open to a prisoner swap, calling it a "possibility, certainly from a humanitarian perspective." But President Trump has vowed not to broker the type of deal that President Obama greenlit in 2016, which unfroze Iranian assets and freed four Americans, including Washington Post journalist Jason Rezaian.

"I didn't do what Obama did, give them $1.8 billion in cash to get back four hostages," Mr. Trump said in a United Nations address last September.

Christine Levinson's husband, former FBI agent Bob Levinson, has been missing in Iran since 2007. His whereabouts remain unknown.

"In order to get anything done the two countries have to speak to each other," Levinson said. "They are being kept from their families, and they need to come home."