I think every single school, especially those teaching teenagers, has problems with violence of some sort among the pupils. You can send your child to the school with the best academic record in the area but there will always be problems with kids trying to be 'top dog' and using their fists more than their mouths.
Say the wrong thing to the wrong person and you might get a whack. Somebody says something you don't like, you have to make the choice between whacking them or dealing with it a different way. It all goes towards learning how to cope with the same situations in later life.
Unfortunately some people don't learn the consequences of making the wrong choice, which is normally the violent choice, and end up doing something they shouldn't.