Connecticut Gov. Dan Malloy tells NBC's David Gregory what he's learned about the school shootings.
By M. Alex Johnson, NBC News
Updated at 2:01 p.m. ET: An explanation still hasn't emerged for why a man killed 26 people at Sandy Hook Elementary School, but it does appear that he attended the school as a youngster, Connecticut Gov. Dan Malloy told NBC News on Sunday.
Adam Lanza, 20, shot his mother multiple times in the head?in her home before driving to the school in her car and killing 20 children and six adults in two classrooms Friday in Newtown, Conn., authorities said Sunday. The gunman then shot himself in the head as emergency crews arrived at the scene.?
"He attended there ? that's what I'm led to believe," said Malloy, who declined to answer whether any documented evidence had been uncovered that Lanza might have been mentally disturbed.
The children ? 12 girls and eight boys ? were all 6 or 7 years old, H. Wayne?Carver, the state medical examiner, said Saturday. Some were shot as many as 11 times, Carver said.
Authorities were reviewing a computer they found at the home of Lanza's mother, Nancy, for possible leads on the gunman's motive, NBC News' Pete Williams reported.
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Lanza's parents were divorced, and he lived with his mother, who home-schooled for part of his childhood, Malloy said.
Connecticut school shooter was 'very nervous around people'
?"He had a very troubled life," Malloy said. "He never seemed to be a good fit. ...?It was a very difficult time for him and his mother.
NBC News' Pete Williams updates with new information on the Connecticut school shootings.
Authorities wouldn't go into details during a briefing for reporters Sunday morning, but investigators told NBC News that they believe Lanza killed his mother, an avid gun enthusiast, with her own gun. He then took three of her weapons with him as he drove to the school in her car.
To bypass security, Lanza smashed in a window, they said. He shot and killed Principal Dawn Hochsprung, 47, and Mary Sherlach, 56, a school psychologist, before proceeding to a classroom, where he found the door locked.
So he ?moved on to a second classroom, where he killed everyone he found, before doing the same in a third classroom, investigators believe. He then shot himself.
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Although he was carrying three weapons, he used only one of them in all of the school killings ? a Bushmaster .223-caliber assault-style rifle similar to the one used by the snipers who terrorized the Washington, D.C., area in 2002. It was purchased legally, they said.
Authorities haven't said how Nancy Lanza stored the weapons.?
Marsha Lanza, Nancy Lanza's sister-in-law and Adam Lanza's aunt, said there was a good reason for a divorced woman who grew up with guns to have them in the house: self-defense.
"She lived alone. She was a female (who) lived alone," Marsha Lanza said.
NBC News Chief Justice Correspondent Pete Williams contributed to this report.
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