NEWTOWN, Conn. (AP) Hundreds of children at Sandy Hook Elementary School survived last year's massacre, but the recovery has been especially difficult for some of the 6- and 7-year-olds who witnessed the shooting.

Among the survivors are a dozen first-graders from the two classrooms where the gunman opened fire with a semi-automatic rifle.

David Posey says his son saw his teacher and a classmate gunned down. He says the boy worried about everyone's safety after the attack and was traumatized by loud noises.

Hugo Rojas is the father of a boy who escaped from the same classroom. He says he struggles with feelings of helplessness because he cannot make his son's nightmares stop.

The gunman killed 20 children and six educators at the school before committing suicide on Dec. 14.