Thank you a lot for such detailed feedback, I really appreciate the time you took to write it down!
You were pretty close to guess who the killer was, it's mainly a matter of choices you make that will help you to find who the killer was.
Polishing is indeed something that needs a lot of time, as for the music I'm not good at composing so I tried to make only a very quick one you can hear at the begining and before shooting, but that's all I managed to make. ^^'