Without having heard the Defence's side we seem to be stuck with varying scenarios. Apart from the screaming and 4 shots do we have any other 'solid' evidence of pre-meditation or intentional murder?
If there was 'solid' evidence, we wouldn't be hear arguing the case for and against.
As the state said, the case is based largely on circumstantial evidence. OP is the only living visual witness to the actual crime, and he has a good reason for not telling the truth, if indeed he has not done so so far.
This was the suspected murder of a woman by her boyfriend, whom she had admitted being scared of, in a country where violence against women is endemic.
It features a defendant's account which, to a lot of people here, begs many questions and has created a sense of incredulity. Maybe he will provide satisfactory answers to at least some of them, although I'm guessing he won't be able to. If he can provide a plausible account of:
what he did between the alleged shots and alleged bat bashes (7 mins plus)
why he didn't phone for help during that time
why it took him so long to bash down the toilet door
why he didn't press the panic button before taking on the 'intruder', or afterwards
why he didn't fire a warning shot
why he kept on firing
why he fired at all when he hadn't even seen the alleged assailant
why he didn't check on RS before moving into the bathroom to take on the 'intruder'
why it didn't occur to him that, even though he thought he heard the window open, he hadn't heard any noises of the 'intruder' entering the bathroom
why it never occurred to him that it could have been RS in the bathroom/toilet (until he'd shot her)
why he claimed RS was still alive over 9 mins after he says he shot her
then maybe I might believe him.