Pistorius and Ordinary Language Philosophy
This story seems tragic for all concerned. I couldn't help but notice, however, that this BBC feature on reactions to the news says "Early media reports suggested that Mr Pistorius may have accidentally shot his girlfriend, believing her to be an intruder".
Anyone familiar with Austin's 'A Plea for Excuses' is likely to remember the famous footnote in which he distinguishes between mistakes and accidents. The details of the Pistorius case aren't fully clear, but it seems that he purposely shot the person in his house - it wasn't an accident, where the gun just went off in his hand. What occurred was a case of mistaken identity: what he thought was an intruder was actually his girlfriend, Reeva Steenkamp. He didn't intend to shoot her, but that makes the case a mistake, rather than an accident. Accidents just happen (befall), whereas mistakes depend on wrong choices.
Austin's distinction sounds plausible to me, but it's interesting (in this and other cases) to consider whether it describes a distinction implicit - albeit imperfectly observed - in ordinary language, or is simply a philosopher's stipulation about terms that, ordinarily, are interchangeable. The BBC's original story, however, does respect the distinction: "Reports say he may have mistaken her for a burglar".