Preschooler hitting and pushing other kids

My preschooler has a slight speech delay and we suspect he has autism (working on an evaluation and he’s in therapy.) Every day I ask his teachers how he did and they say he’s doing good every day. Some days they’ll mention he had a rough time with nap time or biting himself, once or twice they mentioned he got a bit rough with the other kids.

I just went over the incident report from a situation involving my child and one of the teachers. He was chasing other children hitting and pushing them. The teacher went to intervene and (this is where the story doesn’t match up on all accounts) either tripped and her hand landed on him and knocked him down or intentionally pushed him to the ground. Each side says something a bit different and even the teacher herself said something slightly different in all three interviews she had. Anyway. She’s been fired. I can’t help but feel frustrated because something tells me my son is rough with the other kids often and they’re not telling me (how are we supposed to help him if we aren’t being told when he does this stuff?) and we are also feeling guilty that this teacher was fired when our son was acting aggressive with the other children and it even states in the report it’s unclear if she pushed him intentionally or tripped.

So I guess my questions are, is it normal to feel guilty for this teacher getting fired and how do we get through to our child that hitting and being aggressive with other kids is not okay? Is he doing what other kids his age do or is he worse? I just want him to be a good kid.

Edit-I don’t know if this puts anything into a bit of a clearer perspective, but we know the teachers (the one was my softball coach) and this teacher always seemed to love my son, although she had the reputation for being the “mean” teacher because she wouldn’t let the kids do whatever they wanted (completely understandable, this is how she described herself) My son is pretty tall already. About 3’8. She’s a bit shorter so I could see her trip and unintentionally knock him down with his bulky winter stuff on, without falling down herself. The concerning part to me is that in the report one of the other children accused her of pushing him after it happened, to which the child said she replied “no, and my back was turned facing the camera.” She states she didn’t say that, but what 4 year old would make that up? She also changed her explanation of what happened a few times. I don’t know. I don’t want to believe she did it intentionally because she’s been around so long she taught my little sister who is a senior now, and my son loved/loves her. He cried the first day back to school (they were out for a month while this got sorted out) because she wasn’t there. I feel embarrassed my son was acting this way, responsible for all the students missing class and the parents having a hard time sorting out childcare, and guilty by the fact she got fired when the evidence wasn’t clear and they didn’t even bother asking what we thought of it all. At the same time though I’m frustrated because if she didn’t trip and was just trying to get him to stop hurting the others, there’s a million different ways she could have done that without walking up behind him and shoving him down. It stated in the report he cried. He never cries. Ugh I thought his first year of school was going so well and now this😞