Wiping poo on toilet walls in school...

my brother was diagnosed as have aspergers syndrome little over a year ago and only recently about a week ago there was an incident in school where someone had  smeared poo on the walls and this tuesday it happend again. now he didn't own up to me or my parents and he owned up to it today to his teacher and came home and told my dad. now as you can imagine my dad was not happy. now this it totally out of order he would never do anything like that and hasn't until roughly 2 weeks ago. now i am doing a childcare course in college and i have come accross this before i went to college and they say it could be a behavourial problems but i'm just woundering where do we go from here??? now there has been other incidents where he punched one boy in school because he scared them etc help or advice is needed.