I caught a glimpse of a TV ad at the end of the summer announcing a new national hotline:
1(886) SPEAK UP. This number is provided for students, teachers, and parents who hears anything suspicious regarding an individuals threats to hurt anyone at school.
I only saw this ad once, so it is clearly not being properly communicated to the public. I do hope that it will get more air time in the future. It could be key to stopping school shootings. Please keep this number in mind and pass it around.