Students encourage their peers to say something if they see something in a video posted February 21, 2018, on the school's Facebook page.

The day before, a video was posted on the Dalton Public Schools Facebook page after three students reported they found a threatening note in the floor of a classroom.

READ MORE | UPDATE: Teacher in custody after shot fired at Dalton HS

In the video, the school's principal, Steve Bartoo, also encouraged students to speak up if they see something suspicious.

Wednesday, February 28, 2018, a teacher at the school barricaded himself in a classroom. The teacher, identified as Randal Davidson, shot a window at the school. 

This happened two weeks following the school shooting in Parkland, Florida, where 17 students were killed.