US journalist Austin Tice, who disappeared in Syria in 2012, was kidnapped in a calculated operation which was more than a month in the planning, the BBC can reveal.
A member of the group which detained Tice has also claimed the abduction was sanctioned by Syria's leader at the time, President Bashar al-Assad.
Tice was seen getting into a car with a driver he knew and trusted. For years, many assumed they had stumbled upon a government checkpoint, and that the abduction of the journalist had been opportunistic.
But we have uncovered evidence that, in fact, his disappearance was anything but chance.
In a new BBC podcast: Where is Austin Tice? Series 3 of I'm Not A Monster Presents, we reveal the findings of a years-long investigation into what happened to Tice, who had been reporting on Syria's civil war at the time.
His case has been followed closely by international media and cited by successive US presidents.
Georgetown University law student Tice, who had served as a US Marines captain, was last seen in a video - blindfolded and in apparent distress - posted more than a month after his capture.
As the regime fell 12 years later, tens of thousands of people emerged from the administration's prisons. Tice was not one of them.
We obtained co-ordinates from an intelligence source for multiple locations US authorities suspected he could have been held at, and searched for him for more than a month, but found no sign of him.
A former Syrian commander has said Tice was executed. Others have questioned this account and no remains have been found.
But in the aftermath of the regime's collapse, we did uncover secret Syrian intelligence files on Tice - hundreds of pages of internal records providing the first definitive proof that it was the regime that had held the journalist.
Two crucial questions remained unanswered, however: how exactly had Tice been taken in the first place? And, who was responsible for his abduction?
We have spoken to a number of men from the regime involved in Tice's detention, and have reviewed recordings of discussions about it. One man we spoke to, Abu Ali, is a former member of the National Defence Forces (NDF), a militia which was fiercely loyal to Assad.
He says the abduction operation began when Tice's driver - who multiple sources say had been passing the regime information for some time - told a senior NDF member that Tice was moving through rebel-held areas, reporting on the opposition.
Tice had pushed into areas most journalists deemed too dangerous and was writing front-page stories for the Washington Post. The Assad regime was cracking down on anyone highlighting its human rights abuses.
We have been told the NDF member Tice's driver spoke to was Sakr Rustom - not just any NDF militia contact, but nephew of Bassam al-Hassan, one of Assad's most trusted security figures and head of the NDF.
The information on Tice was passed up to Hassan, Abu Ali says, who is then said to have telephoned Assad.
"Bring him to us," Assad replied, claims Abu Ali.
Abu Ali says he was subsequently called into Hassan's office and told the president had approved the operation.
But Tice was not taken immediately. The driver, Abu Ali says, suggested that he and the NDF continue watching him, to uncover more about what he was doing.
"He trusts me," Abu Ali recalls the driver saying.
Some time later, the driver reported back that Tice's actions seemed suspicious, Abu Ali says.
Tice, as a trained marine, would sometimes share his military experience with rebel fighters - according to several people we spoke to - and would correct fighters on how they used their weapons.
To the men watching him, that behaviour made Tice look less like a journalist and more like someone from the CIA. The BBC has found no evidence to suggest this was the case, and a former senior US official responsible for part of Tice's case has denied he was an intelligence officer.
In the days before Tice vanished, the driver made one particularly brazen move while Tice was interviewing rebel fighters. He secretly took the American's backpack, containing his MacBook, a satellite transmitter and other personal items, for regime operatives to look through, multiple sources say.
On 11 August 2012, Tice celebrated his 31st birthday at a rebel safehouse on the western edge of Damascus, a few miles from Assad's presidential palace. There was a swimming pool, Free Syrian Army fighters, Taylor Swift music and whiskey, Tice revealed in what would become his final tweet.
"Hands down, best birthday ever," he wrote.
Then came the time for Tice to leave Syria. He had told various people he was planning to take time out in Lebanon.
But he was not heading to safety. He was heading to a state facility where Hassan had an office, in an area called Tahouneh on the outskirts of Damascus, according to several sources. Abu Ali was waiting there for Tice.
Abu Ali says Tice's driver told him that when he drew up to the gates, he pulled out a gun.
Tice laughed at first, Ali recalls the driver saying, apparently believing the man he trusted was joking. But the driver told Tice he was serious, Abu Ali says, and the journalist realised what was happening.
According to Ali, Tice pulled out his chequebook and pleaded with the driver to name his price, rather than go through with the kidnap.
NDF militia members then grabbed Tice, covering his eyes, Abu Ali says.
Another NDF member told us he would never forget Tice's expression as he realised he had been betrayed. Abu Ali says Hassan immediately called President Assad to tell him they had the American.
For years, the identity of Tice's driver has remained a mystery.
The BBC spoke to more than 20 people to discover who he was, with the trail eventually leading to the city of Homs, and the family of a man called Hamid Abu Obeid.
They confirmed he was the man who had driven Tice away, an account also supported by multiple NDF members. But by the time we identified him, Abu Obeid had disappeared.
His family say they do not know where he is, and fear for his safety. They say they were not aware of Hamid's involvement in Tice's case, and learned about it from him afterwards.
But they did give a motive for his betrayal of Tice.
The Abu Obeid family, Palestinian refugees from Gaza, live in poverty. Under Syrian law they are not entitled to Syrian citizenship and live under significant restrictions.
According to Hamid's brother, he had been promised a passport, Syrian citizenship, a house, and a weapon, in return for delivering Tice - life-changing rewards. But after the abduction, the family says all he got was a pistol.
Then, after Assad's regime fell, Abu Obeid's wife says her husband was called by a man who knew about his involvement in Tice's case and was threatening to tell the US embassy, hoping it might help him secure asylum.
Abu Obeid urged him not to. He then took some money, told his wife he was going shopping, and she says she has not seen him since. She does not know if he is in hiding, or if he has been detained or killed.
Not long after he disappeared, she says masked men - some dressed in military clothes - visited and took a number of Abu Obeid's possessions, including his laptop and other devices.
The wishes of Abu Obeid's wife now chillingly mirror those of Tice's mother and family. On opposite sides of a disappearance that began more than a decade ago, both families are searching for the same thing: a loved one who vanished, and an answer to where he went.
