The only real question is : did she die at the first shot ?
Because he fired several shots, and after the first shot, if she was still alive, she would have been screaming her head off, " Don't shoot, you imbecile, it's me !"
Then is he continued firing, he was trying to (succeeded in) murdering her !
So if all the other shots which hit her were received by her in a lying down position, then he may be innocent, but if not, then he should hang.
Anyway, 5 years for killing anyone (even if you thought he/she was an intruder) seems very little - the 'intruder' was not attacking him, she was locked in a bathroom - hardly 'self defense' !
I reckon he murdered her and should hang, but he has a powerful family, and an international rep - so he walks !
Cheers.