ed lavandera is in arlington, texas. has everything been evacuated from the school? >> it looks like investigators an police here at the scene at the school, which is part of the mansfield independent school district, but inside the city of arlington, in that process is beginning to unfold. you can see there in the distance behind these police vehicles and s.w.a.t. vehicles, there's a fleet of yellow schoolbuses here. what we were told is that as investigators and first responders here have been going through the school securing the scene, making sure no one else was involved in the shooting and searching the school, that those students would begin the process of being escorted out of the building. they're going to be put on those schoolbuses, taken to a nearby performing arts center and then they can reunite with family members. that's where they've asked parents and family to wait for these students to be cleared from the school, but as you