Dd1 is twelve started secondary in September. Shes been settling in well made a few friends and generally happy. Today she arrived home really shaken up. She says she got off the bus and another girl in the same year but in a different form got off as well. Dd says this girl is a trouble maker and she avoids her as much as possible. Anyway the girl asks Dd if shes avoiding her and Dd says no but since they arent friends she has little to say to her. The girl goes a bit mad and proceeds to pull out a 2 inch metal nail file and pushes it towards Dd in a threatening way. Dd says she was really shocked and just ran home without saying anything to the girl. Unfortunately there were no witnesses to the event. I reassured Dd she did the best thing possible under the circumstances but she is very upset. Now Im thinking what I need to do to prevent this happening in the future and if and how I should approach the school. Any constructive advice would be welcomed.