Nancy Lanza was found dead in the Newtown, Conn., home she shared with her younger son. Police believe Adam Lanza killed his mother, and then collected guns registered to her in their home to use in his rampage at the elementary school.

A law enforcement source said that in addition to four weapons connected to the mass shooting -- three on Adam's person, and one in his car -- there were two other weapons found in his mother's home. Police are tracing all six weapons as to where and when purchased and registration, reports CBS News investigative producer Pat Milton.

Two law enforcement sources tell CBS News' Milton that Nancy Lanza was found shot to death in her bed.

CBS News' Bob Orr reported Sunday morning on "Face The Nation" that police found two smashed computers in the home. Law enforcement authorities have collected the computer pieces to see what information might be retrieved.

Neighbors told CBS News that Nancy Lanza was a gun enthusiast and often took Adam Lanza target shooting with her.

The aunt said Nancy Lanza kept guns for own safety, and had something of a survivalist mentality; she was worried about protecting her home if the economy went south.

Money was not an issue for the family; Nancy Lanza received a healthy support payment from her ex-husband, Peter Lanza.

"She didn't have to work. My brother-in-law left her well off," said Marsha Lanza.

A friend of Nancy Lanza, local landscaper Dan Holmes, said he believed that Adam's father was not a large presence in Adam's life. Nancy Lanza evidently still suffered from a bad divorce and could be "pretty vocal" about her ex.

"I don't believe the kids saw their father at all," said Holmes. "She was pretty vocal about her ex-husband... years afterwards."

CBS News' Pat Milton reports source briefed on the investigation said Nancy Lanza was demanding of her children. Even though Adam was highly intelligent, she pressed him to high standards and even pressed her sons to measure up at the shooting range where she taught them to shoot, the source said.

Young residents of Newtown who knew Adam Lanza described him as uncomfortable in groups, shy, and that there was "something off there," reports "48 Hours" correspondent Roberts.

In the chaotic hours after the mass shooting, Adam was initially confused with his older brother Ryan Lanza, who lives in Hoboken, N.J. Ryan Lanza was taken in for questioning Friday but later released. It appears, as of now, that he was not involved in the shooting.

CBS News' Miller notes Adam apparently grew up in the shadow of a more successful older brother.

"He was very different from his older brother, who had gone to college, and gotten a job at a brokerage firm," said Miller.

As CBS News' Miller notes, there's been very little paper trail for the 20-year-old Lanza.

"It's been a mystery. ... He got his GED a few years ago ... but there's no picture of him holding a job or getting higher education."