The shooting tragedy involving Adam Lanza, his mother, and the children and staff at Sandy Hook Elementary was heartbreaking.
The motive for the shooting will remain unknown, but I suspect that Nancy Lanza may have disapproved of something that her son did.
Autistic people do take criticism seriously. They become very angry and cannot distinguish between figures of speech and literal messages. Adam may have taken his mother's words of criticism literally and acted out in his own way.