Dangerous people do not have to be psychopaths.
IMO, since the parents would not make sure their son was safe (or at least would not tell the school about it), this was a reasonable CPS call. In addition, it was a reason to call an emergency CSE meeting to get the child assessed to see if he had a disability interfering with his ability to get an education.
IMO the school neglected to make sure the shooters educational needs were being met by failing to do those two things: call CPS for an investigation of possible medical neglect by the parents, and call an emergency meeting to immediately assess if he needed accommodations to get an appropriate education.
And, once CPS is informed, that does not mean the school just waits for them to fix the problem. They still have their own Special Education steps to take to assess the child.
It gets on my nerves when it seems to me that schools want to be the last resort, not an agency that can act first, perhaps at the same time as other institutions. It seems obvious that there are possible child neglect issues, possible child legal conduct issues, possible parent legal conduct issues, and even possible societal issues which the school can’t control. But there are well-established things the school can do, and it seems to me that there is no reason not to do them immediately, not wait to see if the other systems help first.
(I will reserve my opinions about whether or not the school made legal mistakes until I know more; my opinion is evolving.)