James Grant

If I shoot a gun at a particular person, but I miss, the law recognises that the bullet may easily come to rest in a wall, a tree, or fall harmlessly to the ground somewhere. It could also, of course, strike another person – and this is where things get interesting. This is known in SA law as a scenario of aberratio ictus (going astray of the blow). Our law used to take the view that this was no defence – you still killed a human being. It used to do this by “transferring intent” from the intended victim, to the actual victim. But we have now shifted to the position that recognises that, if you miss your target (although you are liable for attempted murder in respect of your intended victim), whether you are liable for murder, if the bullet happens to strike another person and kill him/her, must depend on whether you had intention (in law, at least foresight) of this prospect.
This is all very different from scenarios of “error in objecto”. It doesn’t matter if an accused intended to kill one person (say, Bill), but killed another instead (say, Jake) – at least not in the sense that the identity of the victim matters. Thus, an accused who intends to kill a particular human body, and kills that human body, incurs liability for murder (assuming capacity and unlawfulness). The mistake involved (“error in objecto”) where one human body is mistaken for another, is an immaterial/inessential error – that is, it does not affect one’s liability. An error in objecto may be material where one shoots at what one thinks is a scarecrow, say, but it transpires that the scarecrow was a human being. This would be an essential/material error and one could not be convicted of murder, which requires the intentional unlawful killing of another human being – one must intend to kill a human being.
The problem is that it is easy to confuse an aberatio ictus (where one misses one’s intended victim and someone else is killed), with the scenario of an inessential error (in objecto) where one shoots at and kill a particular person. The fundamental difference is that in the former (aberatio ictus) there are actually two people/victims, and you kill a person you may not intend to kill. In the second scenario of the inessential error (in objecto) there is only one person/victim and you kill that human being – the human being you intend to kill.
Oscar did not miss his target. He fired at and killed whoever was behind the door. It is therefore no a case of aberatio ictus. It is, at best, an immaterial/inessential error (in objecto) – no defence. Instead, his defence, at least his original defence, is that he did not intend to kill whoever was behind the door UNLAWFULLY. This is a recognised defence. Oscar only needs to raise in the mind of the Court a reasonable possibility that he made this mistake to escape a murder conviction.