Going to school with guns

A student brought a BB gun to my daughter's highschool today and posted it on his Snapchat. Students who saw the photograph immediately went to the teachers and police were called. There was no lockdown. I received a letter which seems to downplay the incident. My daughter and her friend are scared to go to school. I'm scared for them as well. How would you handle this as a parent?

There are shootings and incidents of threats daily in schools.

I want to find a way to bring about some change and never want to have my daughter, or any child near a gun again.