Hours after planes flew into the World Trade Center's Twin Towers on September 11, 2001, Kurt Sonnenfeld was given unrestricted access to ground zero.
Sonnenfeld was working for the Federal Emergency Management Agency, an organisation tied to the US Department of Homeland Security and charged with co-ordinating first response to disasters.
Armed with camera gear, the 39-year-old was asked to film everything he saw. His documented evidence was supposed to form part of a report about what happened, but he never handed back the footage.
His life began to unravel spectacularly in the following months and years, culminating in the death of his wife.
She was found dead on a couch in the Denver home the pair shared with a bullet wound to the back of the head.
Fifteen years later, the now-54-year-old is on the run in Argentina. The US government wants him back in the country. Officially, they say he's wanted over the murder of his wife, but he believes it's something far more sinister.
He says they want to silence him over what he saw beneath World Trade Center 6, evidence he is convinced paints the Bush Administration as big players in the deadliest attack on American soil.
"One thing I'm certain of is that agencies of intelligence of the United States of America knew what was going to happen and at least let it happen," he said.
"Not only did they know it was going to happen, but they in fact collaborated."
The theory is popular among truthers. It is given weight by a similar discovery on a basement door below World Trade Center 4.
According to a New York Times article, the door to a vault was still intact but it appeared as if somebody had tried to gain entry. Behind the vault door were nearly a thousand tonnes of silver and gold.
Sonnenfeld is a conspiracy theorist and not only because of what he saw. He says he has the most trouble understanding how World Trade Center 7 collapsed despite suffering no damage.
"To me, the most suspicious thing of all is what happened to building seven at the World Trade Center," he said.
"This building was not hit by a plane. It didn't have any structural damage ... but, amazingly enough, building seven fell in a perfect textbook type implosion, taking only 6.5 seconds for a 47-storey building to fall completely into its own footprint.
"This to me indicates there was absolutely no resistance between the floors when the building collapsed."
'HE ADMITTED TO KILLING HIS WIFE'
Robert Dreyer and Damian Whitehead shared a jail cell with Kurt Sonnenfeld in the days after Nancy's death.
They said the Denver man initially denied charges against him but later admitted to killing his wife.
In his only interview with US media since moving to Argentina, Sonnenfeld told GQ he could not be certain if he ever met the pair in jail.
"Could've met 'em. I certainly didn't make any friends," he said.
Their testimony doesn't help Sonnenfeld's case. Other evidence collected at the scene also works against him.
Police say when they attended a 911 call, they found Sonnenfeld with blood on his hands and blood spatter on his face. His defence team argued an official line that he embraced his wife after hearing the gun go off and she "coughed and sneezed" in his face.
The problem with that is Sonnenfeld told GQ it didn't happen that way. He said he put his hands on his face moments after tending to his wife and the "spatter" was simply dried blood.
The questions will continue to come but, as long as he is in Argentina, he will never have to answer them officially.
In the documentary, he says he is ready for the harassment to stop.
"At least four times has my case been looked at by a judge and been decided in my favour yet the US government continues and continues," Sonnenfeld said.
"What we want now is for the US government to cease what they're doing. My wife and I now have two beautiful daughters born here in Argentina. I now consider myself Argentinian.
"Of course I miss my (family) very much. I miss the mountains of Colorado. But to me, if I had a chance to go back to the United States, I don't believe I would.
"I prefer it here."