Is this an American thing? Why does a school district have a police force?
It differs from place to place. Police officers in schools of one kind or another are totally common in America, but I'd say it's much more typical to have "school resource officers" drawn from the local police than to have the schools have their own separate police system.
Except the officers are not suspended and will be fucillijg other roles in the district, so pretty meaningless.
They should be fired, denied pensions, barred for life from voting, serving public office and owning or using firearms, and then individually charged with every murder which occurred that day. But I guess this is something.