An American who vanished nearly seven years ago in Iran was working for the CIA on an unapproved intelligence-gathering mission, an investigation has found.
When the case came to light inside the US government it produced one of the most serious scandals in the recent history of the CIA - but all in secret, the Associated Press probe revealed.
The CIA paid Robert Levinson's family 2.5 million dollars to head off a revealing lawsuit. Three veteran analysts were forced out of the agency and seven others were disciplined.
The US has described Mr Levinson publicly as a private citizen. The White House said last month: "Robert Levinson went missing during a business trip to Kish Island, Iran."
That was just a cover story. In an extraordinary breach of the most basic CIA rules, a team of analysts - with no authority to run spy operations - paid Mr Levinson to gather intelligence from some of the world's darkest corners. He vanished while investigating the Tehran regime for the US government.
Details of the disappearance were described in documents obtained or reviewed by the AP, plus interviews over several years with dozens of current and former US and foreign officials close to the search for Mr Levinson.
There is no confirmation of who captured Mr Levinson or who might be holding him now. Although US authorities have investigated possible involvement of drug traffickers or terrorists, most officials say they believe Iran either holds him or knows who does.
The AP first confirmed Mr Levinson's CIA ties in 2010 and continued reporting to uncover more details. It agreed three times to delay publishing the story because the US government said it was pursuing promising leads to get him home.
The AP is reporting the story now because, nearly seven years after his disappearance, those efforts have repeatedly come up empty. The government has not received any sign of life in nearly three years, and senior US officials say his captors almost certainly already know about his CIA association.
There has been no hint of Mr Levinson's whereabouts since his family received proof-of-life photos and a video in late 2010 and early 2011. That prompted a hopeful burst of diplomacy between the United States and Iran, but as time dragged on, promising leads dried up and the trail went cold.
Immediately after Mr Levinson's disappearance in March 2007, the CIA acknowledged to Congress that he had previously done contract work for the agency. But the CIA had no current relationship with him and there was no connection to Iran, the CIA assured lawmakers.
But in October 2007 Mr Levinson's lawyer discovered emails between him and a friend, Anne Jablonski, who worked at the CIA. Before his trip, he told Ms Jablonski he was developing a source with access to the Iranian regime and could arrange a meeting in Dubai or an island nearby.
The problem was, Mr Levinson's contract was out of money and, though the CIA was working to authorise more, it had yet to do so.
"I would like to know if I do, in fact, expend my own funds to conduct this meeting, there will be reimbursement some time in the near future, or, if I should discontinue this, as well as any and all similar projects, until renewal time in May," Mr Levinson wrote.
There's no evidence that Ms Jablonski ever responded to that email, and she says she has no recollection of receiving it. She said she had no idea he was going to Iran.
In a later email exchange, she advised him to keep talk about the money "among us girls" until it had been officially approved.
Mr Levinson said he would try to make this trip as successful as previous ones, and promised to "keep a low profile".
Mr Levinson's flight landed on the island of Kish on March 8, 2007 and checked into the Hotel Maryam, a few blocks off Kish's eastern beaches. His source on Kish, Dawud Salahuddin, has said he met Mr Levinson for hours in his hotel room. The island is a free-trade zone, meaning Americans do not need a visa to visit.
Salahuddin was an American fugitive wanted over the killing of a former Iranian diplomat in Maryland in 1980. Since fleeing to Iran, Salahuddin had become close to some in the Iranian government, particularly to those seen as reformers and moderates.
The hotel's registry, which Mr Levinson's wife has seen, showed him checking out on March 9. What happened to him next remains a mystery.
The emails touched off an internal CIA investigation which discovered that the agency's relationship with Mr Levinson had been unusual from the start.
Instead of emailing his work product to the CIA, he mailed packages to Ms Jablonski's home in Virginia. His correspondence was primarily with her personal email account. Ms Ja blonski said they simply wanted to avoid the CIA's lengthy mail screening process.
The Illicit Finance Group also did not follow the typical routine for international travel. Before someone travels abroad for the agency, the top CIA officer in the country normally clears it so that, if an employee is arrested or creates a diplomatic incident, the agency is not caught by surprise.
That did not happen before Mr Levinson's trips, former officials said. He journeyed to Panama, Turkey and Canada and was paid upon his return, people familiar with his travels said. After each trip, he submitted bills and the CIA paid him for the information and reimbursed him for his travel expenses.
No one who reviewed the intelligence or reviewed the contract ever flagged this as a potential problem, investigators found.
The whole arrangement was so peculiar that CIA investigators conducting an internal probe would later conclude it was an effort to keep senior CIA officials from figuring out that the analysts were running a spying operation. Ms Jablonski denies that.
US investigators say they believe Iranian authorities, if they have Mr Levinson, must know about his CIA ties. He was not trained to resist interrogation and US officials could not imagine him withholding information from Iranian interrogators, who have been accused of the worst types of mental and physical abuses.
In October 2010, Mahmoud Ahmadinejad, the president of Iran at the time, said his country was willing to help find Mr Levinson, but he appeared to suggest he knew or had suspicions that he was working for the US government.
In late 2010 and early 2011, Mr Levinson's wife Christine received a proof-of-life video and photos that the US hoped signalled his captors were willing to negotiate. US 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 US had evidence that Mr Levinson was being held "somewhere in south-west Asia." The implication was that he might be in the hands of a terrorist group or criminal organisation somewhere in Pakistan or Afghanistan, not necessarily in Iran.
US intelligence officials still believed Tehran was behind Mr Levinson's disappearance, but they hoped Ms Clinton's statement would offer a plausible alternative story if Iran wanted to release him without acknowledging it ever held him.
Iran still denies any knowledge of Mr Levinson's whereabouts and says it is doing all it can.
"If any help there is that I can bring to bear, I would be happy to do so," Mr Ahmadinejad said in an interview in September last year.
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 his statements on Mr Levinson are consistent with Ahmadinejad's.
"He is an American who has disappeared," Mr Rouhani told CNN in September. "We have no news of him. We do not know where he is."