If your son has received physical injuries, not from normal playing, true accidents, etc., but from abuse from other children, do not bother with the principal until way after the fact. Go straight to the police. If it is something, like an assault, that the police would be involved in if it happened in the mall or in a park, then it needs to be brought straight to their attention. Then call child protective services. Then call the principal and tell them what you have done. Never, ever, assume they will do the correct thing because I have seen too many weasels and idiots, no offense to anyone in a similar position, in the profession. It is riddled with idiots who have no concept at all that it is their job to protect children, first and foremost, and that includes from each other. Police first, principal last. mg