Police radio traffic from the Newtown school shooting shows emergency responders initially thought there might be two gunmen on the loose and were not aware of the extent of the carnage inside Sandy Hook Elementary School.

But the scope of the tragedy became more evident minute by minute, until authorities at the scene were heard asking for more help: “Call for everything” and “Do you know if anyone brought a mass casualty kit?”

Then, an hour after the first call, the horror of the crime was laid bare as an officer at the scene spoke of “victims” in a closet.

“There’s a teacher and 18 kids there,” he said in a grim voice.

Read more at NBC News