For more than a year, 80-year-old Baquer Namazi has been imprisoned in Iran, held in solitary confinement with a worsening heart condition that has twice required hospitalization.
In another part of Tehran's Evin Prison, Namazi's son, Siamak, is also behind bars, sleeping on the floor because his jailers haven't given him a bed, family members say.
U.S. and Iranian officials had been negotiating a possible release of American Iranian dual nationals imprisoned in Iran — including the Namazis — until talks broke down in the final days of the Obama administration, according to family lawyers.
Now their hopes for freedom lie with President Trump, who prides himself on being a deal-maker but has rapidly escalated tensions with the Islamic Republic.
In the six weeks since Trump took office, officials in Washington and Tehran say there has been no official contact between negotiators. Trump has slapped fresh sanctions on Iran and threatened to renegotiate the deal under which Tehran agreed to curb its nuclear program.
Although retired Army Gen. Michael Flynn — who once described Tehran as the "linchpin" of a worldwide anti-U.S. alliance — resigned last month as Trump's national security advisor, there are other harsh critics of Iran among the president's closest advisors.
Iranian officials have sought to play down tensions with the White House. But the centrist president, Hassan Rouhani, is also trying to fend off a challenge from hard-liners in May elections. In the heat of the campaign, analysts say, a speedy release of prisoners seems unlikely, provoking concern among family members in the U.S.
For Baquer Namazi, "time is quickly running out," said his son, Babak.
The elder Namazi, a retired official with the United Nations Children's Fund, traveled to Iran in February 2016 to try to negotiate the release of Siamak, who had been detained the previous October. He was arrested soon afterward.
Both were convicted at a secret trial of espionage and sentenced last October to 10 years in prison. They were among several dual citizens arrested in Iran in 2015 and 2016 in what was widely seen as a bid by the country's shadowy security establishment to undermine Rouhani's outreach to the West.
Baquer Namazi, who relatives say previously underwent triple bypass surgery, has been held in solitary confinement and was hospitalized last month for five days. Although the reasons for his hospitalization are unclear, he has a heart arrhythmia and may need a pacemaker, his son said.
Last week, Babak Namazi met with State Department and National Security Council officials in Washington to press for a renewed effort to free his father and brother. The Namazis' lawyer, Jared Genser, said the officials indicated that the release of American "hostages" overseas was a top priority of the administration.
Analysts, however, say there has been little sign of urgency. Key positions at the State Department — the starting point for most bilateral negotiations — remain unfilled, including the special envoy for hostage affairs, a post created in 2015.
The department declined to discuss how it is handling specific consular cases, but said in an email, "We call for the immediate release of all U.S. citizens unjustly detained in Iran so they can return to their families."
In January 2016, four U.S. citizens of Iranian descent were freed in a prisoner exchange with Iran that coincided with implementation of the nuclear deal. But Siamak Namazi was not among them.
At the time, a senior Iranian official told then-Secretary of State John F. Kerry that Namazi would be freed within weeks, Genser said.
But talks dragged on, finally collapsing two days before Trump took office. "Now we are starting at square one," he said.
Genser noted that Trump had set a high bar for himself in dealing with Iran. When the Namazis' sentences were first reported in the closing weeks of the U.S. election campaign, Trump tweeted, "This doesn't happen if I'm president!"
But some experts question whether Trump's blustery style will work with Iran.
"The last prisoner swap negotiations took more than one year of prolonged, disciplined and secret talks," said Trita Parsi, founder of the National Iranian American Council, a Washington-based group that has advocated for better ties between the U.S. and Iran.
"Thus far, the Trump administration simply has not shown the political will or the competence to pull something like this off," he said.
Although the U.S. government won't go into details, there are at least two other Iranian Americans imprisoned in Iran.
Art dealer Karan Vafadari, a New York University graduate who lives in Tehran, was detained in July along with his wife, a green-card holder, family members say.
Gholamreza "Reza" Shahini, a San Diego resident, was convicted in October of national security crimes and sentenced to 18 years in prison.
Family members say Shahini has been on a hunger strike since Feb. 15 to protest his treatment at the Gorgan prison in northeastern Iran, where he was being beaten and harassed by prison guards. The guards blew smoke into the asthmatic man's face and threatened to put him in solitary confinement unless he agreed to be treated for malnourishment, according to his sister, Fatehmeh Shahini.
He was later transferred to a clinic inside the prison, where he continues to be monitored.
"His blood pressure is so low, and he is so weak he can't walk," Fatehmeh Shahini said.
She doesn't think he is doing well mentally, either. "When I spoke to him on the phone [a few weeks ago] he sounded different," she said.
Genser said he had spoken to the family of another American who is in Iranian custody but declined to provide details because the family has not gone public about the case.
The whereabouts of a sixth American, Robert Levinson, are unknown. The former FBI agent from Coral Springs, Fla., went missing in Iran in 2007.
Although Iranian hard-liners are unwilling to hand Rouhani a political victory before the May elections, experts say, the precarious health of some of the prisoners might persuade the authorities to release them as a goodwill gesture rather than hold out for a prisoner swap that could take months to negotiate.
"The longer Tehran holds on to the dual citizens, the more the issue becomes a humanitarian and not a political one," Parsi said. "The cost of holding on to the prisoners is greater than the cost of setting them free."
Etehad reported from Los Angeles and Bengali from Mumbai, India.