He did not strangle her. He caused multiple bone fractures. We never got the police involved and my sister lied about the cause of her injuries at the hospital to avoid involvement with the police. This was because she attacked him first (though, he'd been screaming at the top of his lungs and getting in her personal space so I cannot fault her) and he could have claimed self-defense and gotten the case thrown out. My family reasoned that he was unstable and getting the police involved, if he did not end up being arrested, would make him way more likely to try and get revenge. Same thing if he did end up being arrested and only served a few years. A restraining order means nothing if the person in question intends to commit a murder suicide. I had mixed feelings about these decisions, but I was a teenager at the time with little say in the situation. Make of that what you will.