Child getting hurt by special needs child at school

My first grader is being attacked more than once at school by another kid in his class. Not just pushed like attacked and hurt , drawing blood, bending his fingers , screaming in his face, scratching, etc. And this is all on purpose, unprovoked. His teacher even told me my son has never done anything to this kid and is very respectful and tries to stay away from him but the kid is relentless . My son is small so I assume that's why he's a target. When he asks the child to stop he says "no I'll do it anyway" or "I'll just do it again tomorrow".

I've reported this multiple times and it's been recorded and everything BUT because this kid has some sort of undiagnosed issue they keep letting it slide because he "has problems they are working on".

So is this typical protocol because the same thing happened last year with a different kid and I was told he had "behavior problems and was on an IEP" and that it was all being worked on and that there's nothing else they can do because he has special needs. I'm not trying to be an asshole here but I don't care if the kid has special needs my kid keeps getting hurt and I find that completely inappropriate. He's been crying about going to school! Any advice on what I should do ? I'm not pulling him out of school