She brought this man into her home and did not release him. If she had rolled him off of her car by the roadside, she would have dumped an injured man who might have gotten medical attention. She could have been charged with failure to stop and render assistance (hit & run) but here she did not run, she dragged the body home with her. The man's live body was in her possession, under her control.
It is not a stretch to rule this with a kidnapping charge.