I think we've already exchanged messages about this (hi, member of the school committee here), but just to say it here as well: I know the families have now received a message from the school. The police did let the school know that there was no threat to the school (as noted elsewhere, it happened the night before).
District and PD communication is part of what is being discussed with the MOU that is being sorted out between the two, and I asked that the superintendent flag this as an example.
(sorry not to have jumped on this yesterday; I don't always remember to check reddit daily)