In a phone call earlier today with International Paralympic Committee (IPC) President Sir Philip Craven, he told me that his personal reaction was one of "total shock and disbelief" on Valentine's Day when he found out that the South African had allegedly murdered his girlfriend Reeva Steenkamp.
I guess my personal feeling on that February 14 morning was pretty similar, when news reports began broadcasting that the 26-year-old athlete had shot Steenkamp four times with a nine millimetre pistol at his high-security home in Silver Lakes complex in Pretoria, the country's capital.
As the rolling news coverage started to reveal more and more shocking details of the tragic incident, I vividly recalled my numerous meetings with Pistorius.
That first one came in Manchester three years ago, on the eve of the BT Paralympic World Cup in the city where Pistorius was the headline attraction, as he usually was wherever he competed.
The Blade Runner had always been someone who had fascinated me since I first saw him on television at the Paralympics in Athens six years earlier, and I told him that it was a genuine honour to meet him.
He smiled, thanked me, and I had about an hour's one-on-one interview with him later that day, during which time we covered a variety of topics. Back then, he wasn't quite the global superstar he was by London 2012, but he was still pretty big, and he had a stock answers for most of my questions.
Only when I asked him about fame, did his interview guard drop a little.
"It is difficult," he said, his eyes more focused on me than before. "I'm about your age, but everything I do is always all over the news. It gets hard, but it comes with the territory I guess."
We spoke for a while after the interview had finished and, even with London 2012 looming, he talked passionately about competing at Rio 2016, where he said he felt he would be at his peak.
A couple of days later, after he had easily won his two races at the Paralympic World Cup, he asked if he could lean on my shoulder while talking to the media in the mixed zone.
This wasn't to be the last occasion I would perform this role for him, because it turned out he can't stand still on his running "blade" legs due to their shape, so he always has to lean on something or somebody.
The next time we met was at the 2011 IPC World Athletics Championships in Christchurch, New Zealand.
I met him on the training track for an interview and received a warm hug. He said he needed an ice bath before our interview and asked if I wanted to come and watch - as he would be wearing shorts! I politely declined and he laughed, saying that he would come and find me afterwards.
He kept his promise and on a sunny day, we sat in the stands and talked for hours about his Olympic and Paralympics dreams.
It was then that I finally asked for a picture with him. I explained that I was too star-struck the first time we met in Manchester and he smiled. "I'm still very flattered whenever people want a picture with me," he replied, posing next to me with his thumb up.
We spoke a lot at those Championships and at numerous events that followed it. I was always flattered that, despite his growing global stature, he never forgot my face or name.
The last proper conversation I had with him was at the Global Sports Forum in Barcelona nearly a year ago. He came over to me at lunch and I commented on how much leaner he looked than when I had last seen him. He explained it was because he had cut down on sprint training and was doing more work for the 400 metres in his bid to qualify for the Olympics.
I parted company with him that day by wishing him luck in his Olympic quest, and I was delighted to later see him make the South African Olympic team, and to be able watch him in person at both the Olympics and Paralympics.
Despite watching almost all of his races at London 2012 from the media stand in the Olympic Stadium, I didn't speak to him much at the Games. In fact,only once did I manage to snatch a brief word with him.
On that occasion, we shock hands and said hello following a press conference at the Main Media Centre but it was a short chat. He was being mobbed by journalists at the time so I simply congratulated him on making the Olympics. He thanked me, saying that he hoped to speak to me properly in the near future. I'm sad that won't happen now - at least not for a while, it seems.
A few days later Pistorius lost out to Brazil's Alan Oliveira in the 200m T44 final and used a post-race television interview with Channel 4 to claim he had only been beaten because of the length of his rival's blades. It showed an edge to Pistorius that few people had seen before, and I believe it was poorly managed by his PR team.
Much has been read into that incident since Steenkamp's death. But let's face it, it wasn't exactly an obvious precursor to the terrible incident in Pretoria, where the life of a beautiful and clearly talented young woman was unforgivably cut short.
It is a drama that I, like the majority of the world, will be watching closely.
But from the families of this tragedy to the Paralympic Movement and the world of sport, there are no winners in this case. There are only losers on the side-lines as we watch the golden boy of the Paralympics, and a guy who I, like many, believe is a good man, fall so dramatically from grace.
Tom Degun is a reporter for insidethegames. To follow him on Twitter click here.