Washington Post correspondent Jason Rezaian is greeted by U.S diplomat Brett McGurk upon his arrival in Geneva on Sunday. The reporter, formerly imprisoned in Iran, later traveled on to Germany. (State Department)

American officials were adamant. The deal they had reached with Iran to free imprisoned Americans, including Washington Post reporter Jason Rezaian, had always included his Iranian wife. Rezaian, they knew, would never leave Tehran without her.

But as a Swiss plane sat for hours Saturday on the tarmac at Tehran’s Imam Khomeini International Airport, waiting to take Rezaian and two of the other released Americans to freedom, neither his wife nor his visiting mother could be found.

At the White House, there was growing nervousness that something had gone badly wrong in a prisoner deal that was to coincide with the diplomatic triumph announced earlier in the day — final implementation of the Iran nuclear agreement.

In Vienna, Secretary of State John F. Kerry and Iranian Foreign Minister Mohammad Javad Zarif, there for the nuclear ceremonies, held a tense telephone conversation. In Germany, where the released prisoners were due to arrive at a U.S. air base, Rezaian’s brother, Ali, anxiously worked the phones to Tehran, trying to locate their mother and Jason’s wife.

For Rezaian’s family and his employer, who had fought and lobbied for his release, and for the Obama administration officials who ultimately obtained it, the nail-biting denouement was perhaps a fitting closure to the reporter’s 18 months of imprisonment.

Washington Post journalist Jason Rezaian has been freed from prison, according to U.S. and Iranian officials. He was arrested in Iran in 2014 and convicted of espionage last year. Here's what you need to know about the case against him. (Monica Akhtar/The Washington Post)

Even after the plane took off, with all aboard after a delay of more than 12 hours, it was unclear whether the problem had been the result of simple miscommunication on the Iranian side or something more nefarious.

‘Mystified’ and ‘concerned’

On July 22, 2014, Post foreign editor Douglas Jehl received a poorly connected cellphone call from a contact in Tehran. Post correspondent Jason Rezaian, then 38, and his wife, Iranian journalist Yeganeh Salehi, had been arrested, the caller said. Jehl immediately reached out to Jason’s brother, Ali, a biotechnology consultant in California, and to Iranian and U.S. officials.

“We believed, and very much hoped, this was a misunderstanding . . . nothing more than the kind of unpleasant glitch that sometimes happens in Iran,” Jehl recalled Sunday.

Rezaian, a U.S.-born Iranian American, was an “accredited journalist, operating normally, doing nothing wrong,” Jehl said.

But hopes that it could be quickly resolved were dashed three days later when a senior judicial official confirmed the arrests.

Four Americans and seven Iranians were set to be exchanged in a deal linked to the imminent implementation of a landmark nuclear deal between Tehran and six world powers. Here's what we know about who they are. (Jason Aldag/The Washington Post)

Martin Baron, The Post’s executive editor, released a statement saying officials at the paper were “mystified” and “profoundly concerned” about Rezaian’s well­-being.

The State Department said it was “concerned,” but had no further comment due to “privacy concerns.”

At the time, after years of on-and-off negotiations over an Iranian nuclear program that the United States and its allies were convinced had been designed to build a bomb, the West was involved in promising negotiations with Tehran.

Rezaian was not the only American known to be held by Iran. At least two others — former Marine Amir Hekmati and Christian pastor Saeed Abedini — had been convicted on charges that the United States said were bogus.

U.S. officials said they raised all these cases, along with that of Robert Levinson, a CIA contract worker who had disappeared from Iran’s island of Kish in 2007, on the sidelines of every nuclear and other meeting with Iranian officials.

This account of the efforts to secure Rezaian’s release is based on interviews with the Rezaian family, Post executives and senior administration officials, some of whom spoke on the condition of anonymity to discuss diplomatic matters.

Opening back channels

As time went on with little news, concern grew that the administration’s eagerness to conclude the nuclear deal had tempered its zeal to press Rezaian’s case with Iran. Although they were in frequent contact with administration officials, the family and The Post had little information about what was going on behind the scenes.

“They were certainly focused intently and primarily on the nuclear talks,” Jehl said of the administration. “I think we sometimes felt that Jason’s fate was secondary in their priorities.”

Baron, Jehl and other Post editors met with Vice President Biden, Kerry, White House Chief of Staff Denis McDonough, Obama national security adviser Susan E. Rice and counterterrorism advisor Lisa Monaco, among others.

But “all along, the administration was reluctant to get into a lot of details with us,” Baron said Sunday. Although Post executives dealing with the administration and Iran on Rezaian’s imprisonment erected a wall of silence, excluding Post reporters separately covering it as a news story, administration officials “remained concerned throughout, to the very end, that if they provided us details it would somehow end up being public.”

Separately and together, Ali Rezaian and the Post undertook their own efforts, both to open channels to the Iranians, through other governments and private citizens, and to ensure “that the world didn’t lose sight of Jason’s case,” Baron said.

Ali Rezaian started an Internet petition that half a million people signed. Foreign governments were asked to bring it up in their meetings with Iran; Post reporters raised the issue in news conferences and interviews. “Free Jason” pins and posters were liberally handed out.

The Post hired lawyer Robert M. Kimmitt of WilmerHale, a former senior State Department official who was involved in previous hostage releases.

But in Iran, Jason’s health worsened even as his legal situation became even more opaque. In late September 2014, Salehi, Rezaian’s wife, was released on bail. In December 2014, Iran said he would be tried on unspecified charges in a closed hearing; he was denied legal representation and bail. In January 2015, his case was ominously transferred to a branch of the Revolutionary Court, closely aligned with Iran’s intelligence service; shortly thereafter, hard-line judge Abolghassem Salavati was picked to preside over a trial.

An indictment indicated that he was being charged with espionage and other counts that each carried a maximum prison term of 10 to 20 years.

That May, a closed-door trial was adjourned after one day, only to reconvene in June for three hours, and again in July. No details were released.

“It became clear as the process went along,” Ali Rezaian said, “that diplomatic channels weren’t going to be able to solve this problem. . . . Parts of the internal Iranian security apparatus” were going to have to participate “to move things forward.”

With Iran’s ‘decision makers’

Shortly after Rezaian’s arrest, Iranian nuclear negotiators mentioned that there were a number of Iranians in U.S. prisons that they would like to see released. But it was not until the fall of 2014 that it became clear that Iran was proposing an exchange.

In response, the two sides appointed separate teams, uninvolved in the nuclear talks, to begin discussions in Geneva about prisoners. The teams included officials from agencies across both governments including, most importantly on the Iranian side, the Ministry of Internal Security and other “decision makers” outside the foreign ministry.

Several U.S. officials insisted that the two issues were never directly tied — that the United States never indicated that it would alter its position on the nuclear issue in exchange for concessions on prisoners.

Kerry, in an interview Sunday morning aboard his returning plane, said he told Zarif: “We believe they are wrongfully held. . . . You believe they violated something in your system. Okay . . . but it could have a profound effect on the way people perceive your country.”

But the prisoner talks continued in fits and starts, to some extent, Kerry said, because the Iranians haggled over the number of their citizens to be released by the United States. “For a long period of time, this didn’t move because of the people they were asking for,” he said. Obama insisted that no one charged with terrorism or a violent crime would be released.

After a long-term nuclear deal was finally signed last July, U.S. officials said, the tempo of talks on the prisoners increased. In November, when he saw Zarif in Vienna at a meeting on Syria, Kerry said, he thought the prisoner deal was done. “We actually shook hands, thinking we had an agreement,” he said.

But it had again hit a snag over U.S. releases, and a deal was blocked by “some folks back in Tehran in a different department,” Kerry said, declining to identify it.

The missing wife and mother

Early this month, agreement was finally reached on the seven Iranian prisoners to be released. At the same time, it was clear that implementation of the nuclear deal was about to happen. While numerous officials said that they hadn’t planned it that way, they acknowledged that sychronization of the two issues, and the combined diplomatic success they represented, had an undeniable appeal.

For Ali Rezaian and lawyer Kimmitt, there were signs that something was afoot. Regular interrogations that Salehi underwent had taken on a different tone.

Last week in Washington, Jehl said, “we learned from Washington Post reporting that a deal was very close and that it would be prudent for a reporter to get to Switzerland. And we learned from a contact in Iran that Jason and his family [there] had been told that a release was coming very soon.”

But it was not until Saturday morning that they heard directly from the U.S. government that a plan was unfolding.

In Vienna, away from the public ceremony announcing implementation of a nuclear deal, Kerry and Zarif signed an agreement on the prisoners. In Washington, Obama had signed the clemency orders for the Iranians. Switzerland, which handled U.S.-Iranian diplomatic matters on the ground in the absence of relations between the two countries, sent a plane to Tehran.

“We did exactly as promised,” Kerry said. “We wanted to prove to people [that] when we say something, we do it.” Zarif, he said, had “made it very clear we’d get it done, and done well.” The agreement included a stipulation that any “spouses” were allowed to accompany the prisoners.

And then they waited.

Unknown to those in Europe and the United States, Rezaian’s wife had been told by Iranian officials that morning that Jason was about to be released and flown out of the country, but that she would not be allowed to go. She and his mother, Mary Rezaian, who was visiting from California, could go to the airport and view his departure from afar.

For most of the day, they sat in another part of the airport. They had no contact with the outside world — Salehi’s cellphone had been taken away when she was arrested, and neither felt comfortable using one in Tehran. As night fell, they decided to return to Salehi’s apartment in Tehran.

Kerry exchanged numerous calls with Zarif, who said he didn’t know what was going on, but promised to find out and do something about it.

In Germany, where his brother was supposed to eventually land, Ali Rezaian was frantically calling friends in Tehran, trying to find the women. Finally, he said Sunday, “I got them on the phone, told them what was going on, and coordinated with State to make sure they could get taken to the airport.” When they arrived, there were additional problems. Mary Rezaian was not on the manifest.

It was not until 6:58 a.m. Washington time that Kimmitt got a call on his cellphone from the State Department. The plane, with all aboard, was wheels-up.