In a jail cell at an immigration detention centre in Arizona sits a man who is not charged with a crime, not suspected of a crime and not considered a danger to society.
However, he has been in custody for five years.
His name is Ali Partovi and according to the Department of Homeland Security, he is the last to be held of about 1,200 Arab and Muslim men swept up by authorities in the US after the September 11, 2001, terror attacks.
There has been no full accounting of all of these individuals. Nor has a promised federal policy to protect against unrestricted sweeps been produced.
Human rights groups have tried to track the detainees. They believed all of those who had been arrested had been deported, released or processed through the criminal justice system.
Just this summer, it was reported that an Algerian man, Benemar "Ben" Benatta, was the last detainee, and that his transfer to Canada had closed the book on the post-9/11 sweeps.
But now Partovi has been discovered - and the Department of Homeland Security (DHS) insists he really is the last one in custody.
"Certainly it is not our goal as an agency to keep anyone detained indefinitely," said DHS spokesman Dean Boyd. Boyd said the department would like to remove Partovi from the US but that he refuses to return to his homeland of Iran.
And so he remains.
Within hours of the September 11 attacks - before it was even clear if they were over - the FBI was ordered to identify the terrorists who had managed to slip so smoothly into American society and to catch anyone who might have been working with them. The FBI operation was called Pentbom.
When in doubt, the orders came, arrest now and ask questions later. To make this easier, law enforcement officials were authorised to use immigration charges as needed. The risk of allowing terrorists to slip away just because there wasn't ample evidence to hold them on terror charges could not be tolerated.
Thus hundreds of individuals who were not terrorists, nor associated with terrorists, were temporarily taken into city, county and federal custody.
They were caught in their bedrooms while they slept, pulled from restaurant kitchens where they worked, stopped at the border, and even arrested in federal offices where they had gone to seek help.
In the end, then-Attorney General John Ashcroft's call for "aggressive detentions" netted more than 1,200 individuals in less than two months.
The initial reaction to the sweeps was confusion. Politicians, leading civil rights organisations, Arab and Muslim activists, even the Justice Department's internal watchdogs, didn't know how to react.
"There was so much secrecy surrounding the government's policies that it took a number of months before the public and civil liberties groups began unravelling what was going on," said Lee Gelernt, an American Civil Liberties Union (ACLU) attorney.
Then came demands that these individuals must be accounted for.
To date, that hasn't occurred.
"The fact is the US has not come forward with information on what happened to these people, or released their names," said Rachel Meeropol, a staff attorney at the Centre for Constitutional Rights, an advocacy organisation that represents several detainees being held in Guantanamo Bay.
"Our understanding is that the majority of these people who were swept up on immigration violations were then held in detention until they were cleared of any connection to terrorism. We believe that accounts for the vast majority."
Here is what is known: 762 of the 1,200 Pentbom arrestees were charged with immigration violations. Partovi was one of these. Most had violated immigration laws, either by overstaying their visas or entering the country illegally.
Unlike Partovi, almost everyone was either deported or released within a few months.
Of the others, most were released within days. But at least 93 were charged with federal crimes and processed through the courts, and an unknown number were deemed material witnesses.
As the years passed, public concern faded.
Jennifer Daskal, of Human Rights Watch, said: "It really is a black mark on the US. People have lost years of their lives and families have been ripped apart in the frenzy of fear."
In June 2003, the Justice Department's inspector general, an in-house auditor, found widespread abuses in the way immigration laws were used to hold people suspected of terrorism in the months following 9/11.
The inspector general made 21 recommendations calling on the Justice Department and the Department of Homeland Security to formalise policies, responsibilities and procedures for managing a national emergency that involves alien detainees.
Ali Partovi, when asked for an interview, phoned from the Florence Correctional Centre, a privately run detention centre in Arizona where he is held. He was adamant he did not want to say anything.
Partovi doesn't have a lawyer and said he didn't want one.
He did have a lawyer once, when he was arrested in Guam in the autumn of 2001, trying to enter the country on a fraudulent Italian passport.
"He applied for political asylum, but I believe officials thought he might be a terror suspect," said Curtis Charles Van de Veld, who was hired by the federal government to represent him.
Partovi was sentenced to 175 days in custody, which he had already served by the time he pleaded guilty in 2002. Then he was turned over to the Department of Homeland Security.
Until he was 'rediscovered', Van de Veld didn't realise his former client was still in custody.
"I'm surprised he hasn't contacted me," he said.