A former babysitter for Newtown, Conn. gunman Adam Lanza said the boy's mother told him never to lose sight of the Lanza, not even to go to the bathroom.
Ryan Kraft told CBS station KCBS in Los Angeles, he babysat for Lanza while he was a student at Sandy Hook Elementary School in Newtown, Conn. the site of Friday's mass shooting.
USA TODAY reported police said Lanza killed 20 children and six adults before committing suicide. CBS reported Lanza killed his mother Nancy Lanza before heading to the school.
Three years ago Nancy and her husband Peter Lanza divorced. She received $200,000 a year in alimony and primary custody of her son Adam, USA TODAY wrote.
More from GlobalPost: Full coverage: Sandy Hook shooting
Kraft told KCBS when he heard about the shooting, "I just couldn't think for a little while. I was shaking... I'm just numb to it, I haven't really processed the fact that this happened right where I used to be, and that, 15 years ago, it could have been me."
Kraft said Lanza as quiet and "whenever we were doing something, whether it was building Legos, or playing video games, he was really focused on it. It was like he was in his own world."
ABC's Good Morning America said Lanza "suffered from a condition where he could literally feel no pain" according to Richard Novia, the advisor for the tech club at Newtown High.
Novia told GMA if Lanza cut himself, "he would not know it or feel it."
Meanwhile, others who knew Lanza told ABC News, "[Adam] was not connected with the other kids" and that he was "obviously not well."
More from GlobalPost: Sandy Hook shooting: Girl was sole survivor of her grade one class