FBI releases documents on 2012 Newtown school shooting

HARTFORD, Conn. — The FBI has released more than 1,500 pages of documents related to its investigation of the 2012 shooting at Sandy Hook Elementary School in Newtown, Connecticut, that left 20 first-graders and six educators dead.

Many of the documents released Tuesday had large sections redacted. They include reports by agents who interviewed people about shooter Adam Lanza, who killed himself as police arrived at the school.

An unidentified person told an agent that Lanza's mother, Nancy, was concerned about him a month before the shooting because he had become a "shut in" who hadn't gone anywhere in three months. Adam Lanza fatally shot his mother before going to the school.

Several residents told authorities they received death threats after the shooting in phone calls from someone identifying himself as Adam Lanza.