Just that. They occasionally physically fight. It happened today on the walk to school. He is her twin and far more slight than her.
She hit him in the face after he was bating her. She did it a few weeks ago and the area around his eye was marked. He was sobbing and it wasn't faked crying. I told her then never to hit someone in thr face again and it has just again happened.
I don't know how to handle it. She is otherwise an exemplary child. Helpful and brilliant at school. She gets frustrated with him though and lashes out. Because he is smaller he always comes off worse. My natural instinct is to protect him as, even though he was being annoying, she escalates every argument to the extreme.
Please could you advise how to manage as it scares me the feelings she generates in me as a result.