FILE - In this Friday, Dec. 14, 2012 file photo, parents leave a staging area after being reunited with their children following a shooting at the Sandy Hook Elementary School in Newtown, Conn., where Adam Lanza opened fatally shot 27 people, including 20 children. People figure there surely were signs of impending violence. But experts say predicting who will be the next mass shooter is virtually impossible _ partly because as commonplace as these calamities seem, they are relatively rare crimes. Still, a combination of risk factors in troubled kids or adults including drug use and easy access to guns can increase the likelihood of violence, experts say. (AP Photo/Jessica Hill, File)
NEW HAVEN, Conn. (AP) -- Warrants released in the investigation of the Newtown school shooting reveal that an arsenal of weapons including guns, a gun safe with shotgun shells, a bayonet and several swords were found in the home of the gunman.
Investigators also found articles on other shootings and a holiday card containing a check made out to Adam Lanza for the purchase of a firearm, authored by his mother, Nancy Lanza. And investigators found books about living with autism and Asperger's syndrome, as well as an NRA guide to pistol shooting.
Twenty-year-old Adam Lanza killed his mother inside their Newtown home on Dec. 14 before driving to Sandy Hook Elementary School and killing 26 people, including 20 first-graders. He killed himself as police arrived.