Sure thing. Your narrative is absolutely brilliant. You showed so many angles. For policemen, their suspicions weren't conclusive to even charge her and bring this case to a trial. Hower to the reader you've given much more information than to a policeman. The reader sees the character from inside and can see how she was subjected to years-long psychological abuse and how she was ready in her mind - only waiting for the opportunity. When the opportunity came she took it. Her plan and the execution were so brilliant that as we say in Russian a "mosquito wouldn't be able to squeeze its nose" into the armоr of her alibi. )))

You've also right about her strong core. I think the situations similar to this one exist and most of the time don't end up in murder simply because an abused person doesn't have a strong core and either cannot step over a moral boundary or even more ofter is afraid that she won't be able to go through with it.