Rumpole
Formerly known as "Hercule Poirot"
If the Judge accepts OP's version, then it certainly was not premeditated murder. That is the point of the trial?My understanding is that the state must put on their case which is the murder was premeditated. Naturally, that means they believe Oscar is lying. But they don't have to prove he is lying, they have to prove their case. I'm not making any sense but it makes sense in my head. Their case is not he is lying, it's this murder is premeditated, here's why.
The State have to PROVE that OP is lying. (Beyond Reasonable doubt)
If the Judge accepts that OP GENUINELY believed the Intruder scenario.... and he is not nuts to believe that (a reasonable belief to have had), then she will have to evaluate his actions in the context of there being an intruder (in his mind)
If, on the other hand the Judge thinks OP is lying then she evaluates things on that basis... Clearly a heinous crime deserving the full penalty of the law.
It all depends on the Judge resolving the question "is OP lying?" first up. The State have the burden to PROVE OP is lying. The rest would be a cake walk if they got on with that