After watching the police video, I'm getting the vibe that she was probably a little psycho and they had a very toxic relationship. The scratches on his arm and face....when they tried to pull over and she allegedly grabbed the wheel causing the van to hit the curb....Both talking about how he tries to get away from her when she's upset....
I had experience with a CRAZY ex-girlfriend MANY years ago and she would try to push me to the edge, physically attack me and dare me to hit her (I NEVER did). She acted EXACTLY like the police video. After an incident where she had followed me all night, people witnessed her trying to attack me and attempt to jump into my moving car, I was finally able to get a restraining order. One witness thought I tried to hit her with my car, luckily there were multiple or I would've been in BIG trouble. People around me though it was funny. She stalked me, stalked my new girlfriend, damaged my property....I couldn't get away from her and the Police wouldn't help prior to that incident. Nobody would believe that "sweet little girl" could behave in such a way. I'm extremely thankful that I was raised to know not to physically harm a woman and that I had self control.
When you read this, I am NOT defending him or his actions!
My theory is that she pushed him to the point where he lost his cool and hurt her (and there's NEVER an excuse for putting your hands on a woman) or a bad accident happened during his loss of self control...he panicked and ran.
My wife agreed with the theory above that, after a fight, he was dumb enough to leave her alone out there alone or that there's a slim chance she could've even hurt herself after being left alone (something my ex would've done to ruin me).