gunman's evaluation by the yale child study center. >> there is a lot of violence and preoccupation with war, and firearms and things like that. >> and guns played a prominent role in his and his family's life. >> the mother would use this as a way of connecting with her son, and it seemed like it was the only thing that she could. >> and on december 14th, for reasons still unknown, he shot his mother to death, before killing 20 children, and six staff at sandy hook. >> there is no evidence that any provider, anyone in his life, every thought that he would actually act in such a violent way, or anything close to that. >> an investigation by the connecticut states attorney found no motive. >> so we ask about what could've been done differently? to bring about a difference result. i want to underscore, again the lack of a direct line between mental illness, even untreated, and violence of this nature