NEWTOWN, Conn. —
Education officials said they had found no link between Lanza's mother and the school, contrary to news reports that said she was a teacher there. Investigators said they believe Adam Lanza attended Sandy Hook many years ago, but they had no explanation for why he went there Friday.
Authorities said Adam Lanza had no criminal history, and it was not clear whether he had a job. Lanza was believed to have suffered from a personality disorder, said a law enforcement official who spoke on condition of anonymity.
Another law enforcement official, also speaking on condition of anonymity, said Lanza also had been diagnosed with Asperger's, a mild form of autism often characterized by social awkwardness.
People with the disorder are often highly intelligent. While they can become frustrated more easily, there is no evidence of a link between Asperger's and violent behavior, experts say.
The law enforcement officials insisted on anonymity because they were not authorized to discuss the unfolding investigation.
Richard Novia, the school district's head of security until 2008, who also served as adviser for the high school technology club, of which Lanza was a member, said he clearly "had some disabilities."
"If that boy would've burned himself, he would not have known it or felt it physically," Novia said in a phone interview. "It was my job to pay close attention to that."
Contributing to this report were Associated Press writers Jim Fitzgerald, Bridget Murphy, Pat Eaton-Robb, David Klepper and Michael Melia in Newtown; Denise Lavoie in Danbury, Conn.; Adam Geller in Southbury, Conn.; Stephen Singer and Dave Collins in Hartford, Conn.; Pete Yost in Washington and the AP News Research Center in New York.