His 24-year-old brother Ryan, who was initially named as the shooter, told friends that he thinks his developmentally disabled brother may have committed the crime.
A source told The New York Post Ryan has told investigators he last saw Adam in 2010 and that Adam is autistic.
Nancy Lanza, Adam’s mother and a kindergarten teacher at the school, was found dead at her residence in Newtown.
Matthew Keys of Reuters reports that the guns used in the shooting were legally purchased and registered to Nancy Lanza.
The Post reported that Adam Lanza “had a dispute” with his mother.
An official told the Post that Lanza’s girlfriend and another friend are missing in New Jersey.
More to come as it becomes available.