I first met Fatima Khan in the Syrian embassy in Beirut early this year. She was pleading for a visa so that she and her daughter Sara could visit Damascus and seek news of her missing son. I knew nothing of Abbas Khan, but – aware that I had a visa waiting for me – I promised to find out anything I could once I reached the Syrian capital. Sara told me the story of her brother Abbas, his birth in London, his marriage and children, and of how – moved by compassion for the suffering of civilians in rebel-held areas of Syria – he had crossed the frontier from Turkey to take medical equipment to Aleppo last year.

There had perhaps been an argument with others there, as to whether the equipment should be sold or given away. Abbas was donating the medicines free. He was taking a walk down a road he thought safe when he was seized by Syrian government forces. Did they know he was coming? How was he captured? The family had no news – but they were sure he was alive.

I made my way to Damascus and raised the disappearance of Abbas Khan with several Syrian government officials. They were sympathetic. They wanted to help. I said that if we could establish that he was alive and in a security prison, I would like to see him – so that I could at least confirm to his family that he had not been killed. But after several weeks, I was informed that ‘state security’ was handling the matter, that Abbas Khan’s case was in the hands of higher officials in Syria, and that – and this was only an assumption on my part – the Syrian government might be trying to deal directly with the British authorities.

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I decided to step back. Not least when I heard that Fatima Khan had herself been offered a visa to Damascus and was able not only to visit Syria but to see her son and ensure that he was transferred to a more lenient prison and to hire a lawyer for his appearance in a Damascus court. Mrs Khan visited various ministries and the Czech and Russian embassies, asking all the time for their help in releasing her son. As she obtained further visas, it seemed that Abbas Khan was safe. However long it took, he would be returned home.

And it became increasingly evident that President Bashar al-Assad himself was involved in the case. Mrs Khan would never have obtained access to her son without presidential permission. And it was not difficult to see how, after the West abandoned its military options against Syria under Russian duress – and after the British and American people expressed their refusal to embark upon another Middle East war – Syria’s international status was, to some extent, redeemed.

There were no more calls from Barack Obama for Assad to “step aside” or “step down”. There were no more claims by John Kerry that Bashar was Hitler or worse than Hitler. French foreign minister Laurent Fabius no longer announced – as he did more than a year ago – that Bashar no longer deserved “to live on this planet”. Assad’s enemies were increasingly identified with al-Qaeda – an enemy of the West infinitely more frightening than the Syrian regime. Assad was in a perfect position to release a British citizen – to George Galloway whom he knew personally – and obtain the gratitude, however churlishly given, of the British government.

And then it all went wrong. Abbas Khan was dead. And Faisal Mokdad, the Syrian foreign minister – a decent and intelligent man – was forced to explain a suicide which I frankly do not accept that he himself believed. What happened?

Back in 2005, when former Lebanese prime minister Rafiq Hariri was assassinated in Beirut, the world blamed Bashar al-Assad. Bashar denied this – and an American journalist who was with him when he heard the news of Hariri’s death described Bashar’s surprise. Then word got around that Syrian state security had their own reasons for wanting Hariri dead – they believed he was plotting with the French to destroy Syrian power in Lebanon and thus decided to kill him – even if this provoked an outcry which would force Syrian troops to leave their satrapy in Beirut. Treachery is a more powerful emotion than real politic.

But if this is true, then the implications are now made manifest in the death of the young and brave Abbas Khan. A man whose life last week was more valuable to Assad than any other foreigner’s in Syria was suddenly ‘found’ dead in a state security prison, on the very eve of his release to a British MP who is a trusted figure in the Assad household. Was someone trying to destroy the Syrian president’s steadily improving if still frozen relations with Britain and the US? Who would want to prevent such an improvement? Saudi Arabia? Of course. Qatar? Absolutely. Israel? Why not? But to suggest than any of these three could engineer the killing of a young Englishman in a Damascus prison is surely preposterous.

In the coming days, we shall assuredly find out more. Assad will be among the keenest to know what happened in the cell in the Kfar Soussa prison where Abbas Khan – so happily awaiting his release and to be reunited with his family in London – ended up hanging from his pyjamas on the very eve of his freedom. How did he die? is one question. Who killed him? is quite another.