That is simply apalling, the way she viciously grabbed and tugged the other girl's hair, punching her face, and even attempting to stomp on her head. The monster then returns to attack once again, doing the same, loathsome tactics. The kid, having some sort of immediate response tries to defend his sister, but is then thrown on the ground in a vain attempt.
The part that greatly upset me was when the victim exclaimed, "What did I do?"
This is simply disgusting and loathsome, I hope this "nook" person gets a long and cruel time in prison.