Rosen took in six children who had fled to house, next to the Sandy Hook firehouse, and helped reunite them with their parents Friday afternoon.
"They were just so distressed. They were crying and talking...they had witnessed some of the bloodshed," Rosen said, visibly shaken as he spoke on "CBS This Morning: Saturday."
He said the children were between six and eight years old, and added that they were "sweet," "brave," and "talked about a gun."
Rosen described the scene at his home, as he started calling and waiting for their parents to arrive.
"One little girl was inconsolable. The boys and and the other two girls, they were very composed...I think they were very shocked. But they were brave."
He added that the children kept repeating, "'I can't go back to that school.'
"They just kept saying they couldn't go back to the school," Rosen explained, adding, "One of them said they had seen some blood...one of them said there was a big gun and a little gun."