A case of mistaken identity at Guantanamo Bay
It is more than four years since I first heard the name Omar Deghayes.
His family, who were based in Brighton, were at their wits end.
Omar, their son and brother was being held in Guantanamo Bay.
The United States deemed him to be a terrorist. The evidence? A jihadi video from Chechnya in which Omar Deghayes was said to feature.
The family had not seen the video, which had been found in an apartment in Madrid.
The formidable Spanish judge, Balthazar Garzon, was demanding the Americans hand Omar Deghayes to Spanish police so he could help with their inquiries - the notion was that he had been linked to the cell responsible for the Madrid train bombings which killed 191 people.
Omar, who had only recently become a devout Muslim and headed east, was in deep trouble.
Later that day, through contacts in Madrid, I secured a copy of this all-important video.
His brother, Taher, watched as the murky, ill-focused footage revealed jihadists in conference around a table and then roaming outdoors, mugging for the camera on the Chechen hills.
We came to a close-up of a well-fed, bearded character on whom the Spanish police had superimposed the name "Omar Deghayes".
Taher exhaled and beamed: "That's not him! No, it's not him."
He then went through all the different reasons this was most certainly not his younger brother - the nose, the eyes - there was no resemblance.
And wouldn't he recognise his own brother? He'd known him literally all his life, even before the family had fled their home in Libya after the assassination of their father, a prominent lawyer and opponent of President Gadaffi.
We put out a film on Newsnight telling the story of Deghayes, showing the video and letting Taher state his case.
But this was a brother supporting a brother (and I use the word in the familial sense). He would proclaim mistaken identity wouldn't he? We could not reach any firm conclusion.
A few days later I received a call from the BBC's monitoring service at Caversham, the people who follow with diligence the fine detail and daily shifts of international affairs.
Paul Tumelty, a researcher with great expertise in the waning fortunes of Chechen jihadists, said he had seen our Newsnight piece and had instantly recognised the man named in the video.
He was "100% certain" this was in fact a notorious jihadist. And that he certainly was not Deghayes but one "Walid", a warlord who had been much feared. Past tense. Walid had been dead for a year or more, killed fighting the Russians.
At this point one would like to say we ran that story and Deghayes was on the next plane home from Guantanamo Bay. Sadly, only the first part of the sentence is true.
It was almost three more years before Omar Deghayes was released.
As he tells it, his US captors simply replaced one set of false allegations with another - a pattern he claims was familiar throughout his incarceration.
His account of what happened during his years of imprisonment - in Pakistan, Afghanistan and Guantanamo - is both fascinating and troubling.
It poses further serious questions as to how the US behaved in the War On Terror and to what extent British intelligence was complicit.
Omar says it is good to be back in Brighton. After so often being the subject of interrogation, now he would like some answers of his own.
Watch Peter Marshall's interview with Omar Deghayes on Newsnight on Friday 19 June, then online at the Newsnight website.