NEWTOWN, Connecticut: Police have confirmed they discovered a fourth weapon associated with the mass killing at Sandy Brook Elementary, a shotgun found in a nearby car.
It was earlier confirmed that Adam Lanza, who shot himself after murdering 20 children and six staff, was found with two semi-automatic hand-guns – one of which he used to shoot himself – and a semi-automatic military style rifle, which he used to shoot his victims.
The Connecticut chief medical examiner said on Saturday that of the seven victims he performed autopsies on, all had suffered between three and 11 gunshot wounds, and he believed all the other victims had been shot more than once.
Police have confirmed Lanza fired hundreds of bullets in the attack, which is thought to have taken less than 10 minutes.
Police say the weapons were registered to Lanza's mother, whom he shot several times in the head sometime before he went on to attack on the school.
Police told the Hartford Courant she may have been asleep when she was shot as she lay in bed in the sprawling Newtown house the two shared. Nancy Lanza and her gun collection have become a key element of the expanding investigation into the shooting.
According to police records five firearms were registered to her, but the New York Daily News has quoted a friend of Ms Lanza saying she believed her collection was much larger.
Publicly Ms Lanza was a contended and engaged mother, but privately she struggled with raising her younger son, Adam, the Los Angeles Times reported.
"I know she had issues with the school . . . in what capacity, I'm not 100 per cent certain if it was behaviour, if it was learning disabilities, I really don't know," her sister-in-law Marsha Lanza told reporters.
"Adam, he was . . . definitely the challenge to the family in that house," Marsha Lanza said. "Every family has one. I have one. They have one . . . But he was a very bright boy, he was smart."
It is understood Ms Lanza ceased working at times to homeschool Adam, and battled with local officials over his education.
It has been reported that Ms Lanza was as survivalist. The London Daily Mail quoted Marsha Lanza as saying, "She was stockpiling food. We talked about prepping a lot. She was getting ready for the economic collapse.
But local friends of Ms Lanza have approached reporters in Newtown to say that this was not the woman they knew. One told CNN she was not some "wacko" but a friendly, happy dignified woman with "a lot of class".
Another said she did enjoy shooting and taking her children to a range for target practice, but was responsible and careful.