Oscar Pistorius Judge
Thokozile Masipa the Oscar Pistorius murder trial judge, made a very obvious 'error of law' that no one saw coming.Reuters

The judge presiding over the Oscar Pistorius murder trial, who ruled out the charge of 'premeditated murder', actually made a very obvious 'error of law' that no one saw coming and that could not only set Pistorius free, but also help prosecutors appeal again.

A top South African legal expert has said Judge Thokozile Masipa made a mistake while interpreting the law on Thursday when she acquitted the Olympic champion of the gravest charge against him.

The bone of contention that has occurred over the verdict is on the mysterious term called "dollus eventualis" that the judge uttered repeatedly on Thursday. Under South African law, to be convicted of that charge, which in Latin simply means 'common murder,' a person had to have known those shots he fired would be deadly.

In this particular case, the Paralympics champion killed his girlfriend Reeva Steenkamp when he fired four shots through the door of a toilet cubicle, thinking that he thought a burglar had broken into his Pretoria home.

"The judge got it right when she ended up concluding that it doesn't matter who was behind the door, so as long as there was intention to kill whoever was behind the door," New York Daily News quoted James Grant, who teaches law at the University of Witwatersrand.

But the judge went ahead one step and focused on "whether he foresaw the possibility of killing Reeva behind the door," Grant said, "She concluded that he couldn't possibly have foreseen the possibility of killing Reeva, because at that point in time he thought she was in the bedroom," But that, according to the expert was not the "right question."

Grant told the newspaper that a different answer would have come if the question was: "did he foresee the possibility of killing whoever was behind the door?" And the right question should have been that.

The judge on Thursday concluded that "the state clearly has not proved beyond reasonable doubt that the accused is guilty of premeditated murder," and left it until Friday to decide if he was guilty of 'culpable homicide'.

But since there is no minimum sentence for that crime in South African law, chances are that Pistorius will walk free anyway.