now from chattanooga a city in mourning. dispatch tapes released. what are we learning? >> reporter: they're begun to give you a sense of horrific imagery they found when they came across the scene. of course, they knew it was a school bus accident but you don't know how bad in you're there. listen to what they found. >> i have an mvc with a school bus. the bus is flipped over, occupied with children. it's going to be an mbc involving a scoot bus flipped over with children. they believe there are ejections. >> i can see an arm moving but i don't know if anybody can get to it. >> reporter: so you hear the description of ejections, children being thrown from the bus and then that last call where you hear the description of an arm waving out of the bus and authorities aren't sure how they'll get to them. it took firefighters hours to eventually free all the children from inside the wreckage. the shock in this community is