My local elementary school locks their doors. But since the doors are glass, they would last just two seconds against a determined intruder.
My raw news live feed (mentioned above) just showed a window ripped out of its casement laying on the ground next to the school. Maybe he ripped it out to get in. (Although I guess the more logical explanation would be that some teacher etc. pushed it out so students could crawl out to escape.)
This is true... so very sad