Or some other valid questions:
How come the robber, who had entered the house and most likely noticed someone was home, went to the bathroom, closed the door and started to make noise. What was he gonna steal anyway? medicines? Is it worth it to break into a gated community with guards and rich ppl to raid their bathrooms? Makes no sense.
How come Pistorious didn't use his fully functional ability to speak and told his gf to call the police BEFORE seeking confrontation with a potentially armed robber. Why would he tell he AFTERWARDS (and find she wasn't there). So the idea was to wake her up to gunshots and freak her out completely? or potentially get killed himself in a fight with a robber and have no help on the way? His body is crippled, not his brain.
In the same way he should also have screamed at the intruder before firing and heard a womans shocked reply. He claims to have done that. In that case why wouldn't his gf respond to Pistorious mistaking her for a robber?
How did he hit the "robber" so perfectly with multiple shots though a locked door unless the robber actually were standing right behind the door and he knew that and was having an argument with said person? A real robber wouldn't stand still behind a door getting caught and wait for the police. He would've made an attempt to escape right away, as soon as Oscar called out.
In short the story has more holes than his practice targets at the shooting range.
My own theory: Oscar had been drinking too much, he and his gf had a major fight, she escaped his "wrath" by locking herself into the bathroom. Oscar got even angrier and went for something to get the door up. His gf probably didn't know he had gone for one of his guns and was arguing/threatening to leave him through the door, Oscar fired his gun a few times in a fit of rage.
If the prosecutors use witnesses from neighboors and security guards in the area they can most likely prove the fight between the couple on said evening/night, loud bangs following since he didn't use a silencer, and it will be downhill from there because it will torpedo his own story. Technical evidence can easily prove how close he was to the door when firing and how close she was to the door on the other side when getting hit, including various other things that put even more holes in his story.
In short: game over. Question is more if he can escape murder in the first degree and get a less severe charge, most likely by using the fact he could have been mentally unstable due to alcohol abuse/drug abuse