Your statement is exactly why I am concerned he could get away with her murder and make no mistake: I believe he killed her and her death has been ruled a homicide. We don't know he cause of death what evidence the killer left behind but his argument (if he didn't kill himself) at trial will be that they had an argument and he left her, and when he left her she was fine. Ask yourself this question- if that was true, why wouldn't he tell the police that very story- but no, he didn't talk to the police - because he is hiding the truth and now he is running (which equal consciousness of guilt).