TO my knowledge I have only ever met one murderer. He was genial, fascinating company and easy to talk to. I bought him a malt whisky, which he rolled round in the glass as if it was a secret elixir.

He was not a murderer at the time and the thought that he would ever become one was the stuff of wild fantasy. His name was Oscar Pistorius. A few hours earlier we had hosted a promotional diner in Manchester Town Hall in advance of the Paralympics in 2012, which Channel 4 had secured the rights to broadcast.

Channel 4 was about to embark on the biggest live event in its history. Oscar ­Pistorius, famously known as The Blade Runner was the poster-boy of Paralympic Sport and at the time was challenging both logic and the rules of sprinting by seeking to qualify for the Olympics, and become the first disabled athlete to star in the greatest show on earth.

The highlight of the night was when ­Pistorius delighted the audience by ­producing his famous blades and passing them around, allowing guests to witness them close-up and marvel at how these sleek pieces of polymer reinforced by carbon-fibre, had disrupted sport and re-framed our perception of disability. These sleek pieces of technology had provoked one of the most far reaching debates in world athletes, whether a double-amputee could run faster than the wind.

After the dinner, we returned to Pistorius’s hotel where I bought him a night cap. Because I was a Scot, he asked for an expensive malt. Disguising that it was a subject I knew nothing about I bought him a double Dalwhinnie. We talked for about half an hour and he left, the water of life left untouched on the table.

One thing has stuck in my mind ever since. I asked Pistorius how many blades he had and whether there was anything that differentiated them. It was a bit like asking a professional footballer what boots he wears. He explained that he had many sets of limbs for different occasions and the set he cherished most were a pair he had worn since his teenage days. He described them as his slippers, they were old wooden legs that bore the scratches and marks his dog made when he lay next to him gnawing on his false limbs. It was a warmly reassuring conversation a ­million miles removed from murder.

Back at Channel 4, to represent the complexity of the project we were working on I drew up a strategy document which was jokingly called “Donald Rumsfeld’s Guide to the Paralympics”. It was based on the US Secretary of Defence’s famous briefing on terrorism to the Department of Defence – “we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns—the ones we don’t know we don’t know. And if one looks throughout the history of our country and other free countries, it is the latter category that tends to be the difficult ones.”

And so, it proved for the Paralympics. We knew that it was the first time that the Paralympics had not been broadcast by the BBC so comparisons would be made and the pressure was on to be confident from the start. We also knew that ­people expected Channel 4 to do something ­different so we hired the rap-assassins, Public Enemy to make the theme music and commissioned The Last Leg, a late night entertainment show with disability at its heart. We also knew that ­Paralympic classification is notoriously confusing and that viewers would want to know why Pistorius is classified in T43 category as double below-knee amputee.

We then moved on to what we didn’t know. A survey was sent around every department from Finance to Engineering to gain the wisdom of the crowd: what might happen that we could not foresee? Among the most common responses were a ­terrorist attack on London, a power ­outage in the Olympic Park and a ­catastrophic failure of broadcasting ­legislation that would invite an Ofcom ­enquiry. In a staff of over 1000 people, not a single person ventured that our poster boy Oscar Pistorious would be arrested for killing his girlfriend. Rumsfeld was right.

Last week, I spent a few reflective hours watching the BBC’s Storyville documentary seriesThe Trials of Oscar Pistorius now available on BBC iPlayer. Daniel Gordon’s documentary launched into a storm and the BBC was forced to remove the trailer for failing to even name Reeva Steenkamp, thus feeding the notion that the victim was less relevant and that it was a celebrity film intent on recuperating Pistorius’s reputation. That may have been a perception from the trailer but it is not true of the film, which is delivered over four fascinating parts, and pursues numerous strands of this beguiling story.

Inevitably I asked myself if there anything in my dealings with Pistorius which admittedly short and often through intermediaries, that gave a clue to his capacity to kill.

He had always seemed a very genial character, obliging when required to help promote his sport and never obnoxious the way some superstar personalities can be. The only small insight I had into a different personality was immediately after his big race in London when he caused unpredictable controversy by criticising the blades that a rival sprinter, Alan Oliveira of Brazil had used. Pistorius raged at the cameras saying is rival’s blades were too long and gave Oliveira an unfair advantage in the race. Having failed to win on such a global stage he exploded in a blind temper which took hours to calm down. The documentary pursuing his murder trial found other moments when Pistorius become consumed by a volcanic rage that seemed to blind him to logic.

The documentary seizes on his volcanic anger in the period before the murder. Had it stopped there it would have been a routinely predictable, crime show. Fortunately, it went much deeper.

The judge in the trial was a black African woman from Soweto, called Thokozile Matilda Masipa, whose young life was shown in flashback. Her story in apartheid South Africa contrasted powerfully with Pistorious’s much more privileged life within a wealthy Afrikaans family and at an expensive boarding school. That too was complicated by his disability and in some scenes he is stripped of his Blade Runner persona and shown uneasily walking around on his uneven stumps.

Another fascinating storyline pursued the “intruder myth” in which wealthy white South Africans absorb the idea that they are under attack and so, heavily armed, stay locked up in gated communities fearful of the intruder. It was an intruder that Pistorius implausibly says he was aiming his gun at when he killed Steenkamp.

One scene resonated powerfully for me. Pistorius is in the dock and breaks down melodramatically apologising to Reeva’s family and begging for forgiveness because he had “failed to protect her”. It is an uneasy moment. He had been out of jail on bail for months and had not written or contacted the family to convey his sorrow. It was as if he needed an audience and cameras before he could emote.

On the night I met Oscar Pistorius, he held a room spellbound with his remarkable story. What I did not see on that ­occasion was his uncontrollable rage and his need to be the centre of attention. Nor did I see a man so insecure that he could not bear the end of relationships.

Even sitting down, with prosthetic lower legs, he was the consummate performer, the murderer you’d never detect.