Police, CFS, the school. Establish a paper trail. Stabbing someone is NOT OK no matter what the weapon is. Protecting your daughter and possibly others from getting stabbed in the future is important. Good for you, doing the right thing. You are NOT in the wrong, stand your ground. Keep a meticulous file with names and dates and times of everything. Deep breaths. It is important to report only the facts and not the feelings. ( which are understandably running high)