By Michael Martinez and David Ariosto
NEWTOWN, Connecticut (CNN) -- The mother of the man identified by authorities as the gunman behind an elementary school massacre liked to play parlor games in a ladylike setting with neighbors, discussing their landscaping and backyard gardens in this charming exurb some 60 miles from New York City.
Nancy Lanza was a personable neighbor who lived on a block of spacious houses on a crest overlooking gentle hills, acquaintances said.
She and her family moved to the Sandy Hook neighborhood about 1998, raising two sons with husband Peter until the couple separated a few years ago.
"It was just a nice, normal family," neighbor Rhonda Cullen said Saturday, recalling a recurring neighborhood ladies night over the Bunco dice game.
"We used to joke with her that she'd do all this landscaping that no one could see because it all was in the back, and because her house was so set back," added Cullen.
At odds with this image of New England gentility was how the Lanza household possessed of a cache of weapons -- including an assault-style rifle and two handguns -- in a community prized for its stillness.
Those weapons were found with Nancy Lanza's younger son, Adam, 20 -- whom three law enforcement officials said was the gunman in Friday's mass shooting at Sandy Hook Elementary School.
After gunfire at the school killed 20 children and six adults -- the second deadliest school shooting in U.S. history -- the shooter killed himself, officials said.
Before Friday's rampage, Adam Lanza killed his mother in her home in Newtown's Sandy Hook community, after which the school takes its name. Adam was living with his mother, two law enforcement sources said. The other son, Ryan, was living in New Jersey.
"Something doesn't add up," said Cullen, who was struggling to make sense of the weaponry and the carnage.
A local landscaper, however, said Nancy Lanza was a gun collector and showed off a rifle she had recently purchased.
"She told me she'd go target shooting with her boys pretty often," said Dan Holmes, who owns a landscaping business.
The three weapons found with the body of Adam Lanza at the school were legally purchased by his mother, Nancy Lanza, a law enforcement official familiar with the investigation told CNN.
Neighbor Gina McDade said Nancy Lanza was a "stay-at home mom" and not a teacher or part-time employee of Sandy Hook Elementary, as some media reports stated.
Nancy Lanza had earlier worked in finance in Boston and Connecticut, said a friend who knew her well but who didn't want her name published. Nancy Lanza had retired or was on a break from her career, but she was not a teacher, the friend said.
The friend said Nancy was devoted to her sons and had been "caring for Adam," but would not provide further details.
A residential booklet in the Bennetts Farm Area states that Adam Lanza's hobbies are soccer, skateboarding and video games and that Ryan Lanza's are baseball, rollerblading, bicycling and video games, too.
Four years ago, the Lanzas' marriage was ending.
Nancy Jean Lanza sued Peter John Lanza for divorce on November 24, 2008 -- three days before Thanksgiving, Connecticut court records show. Nancy Lanza checked off "yes" for financial disputes but "no" for parenting disputes, records show.
They were divorced in September 2009 after an uncontested hearing, records show.
Peter Lanza is tax director and vice president of taxes for GE Energy Financial Services in the New York City area, according to his resume posted on the website LinkedIn. He has been an adjunct faculty member at Northeastern University in Boston since 1995 and also teaches a partnership tax class in the master's in taxation program at Fairfield University in Fairfield, Connecticut, his LinkedIn page states.
On LinkedIn, he wrote summaries about himself, including: "Career dedicated to developing and refining partnership tax planning and transactional skills" and "Work closely with many of the preeminent partnership tax advisors in the United States on a daily basis."
Hours after the shooting Friday, a reporter with the Stamford Advocate found Peter Lanza as he pulled his blue Mini Cooper into his driveway in Stamford, Connecticut.
Peter Lanza was apparently unaware that his son was behind the school massacre and his ex-wife had been killed, the newspaper reported.
Peter Lanza told the reporter, "Is there something I can do for you?" and then declined to comment upon being told of his family's involvement in the shooting, the newspaper reported.
An unidentified neighbor told the Advocate that Peter Lanza and his new wife, who has been living in the neighborhood for at least a decade, were married fairly recently.
"I literally know nothing about them. We've been here 10 years, and they've been here longer than that; they're just not very friendly," the neighbor told the newspaper and asked not to be identified.
Peter Lanza was taken in for questioning, but there was no indication he would face any charges, one U.S. law enforcement official told CNN.
The older son, Ryan, was taken into custody for general questioning Friday from a home in Hoboken, New Jersey, according to three law enforcement officials. They did not label him a suspect.
The more complicated story of Adam Lanza was still being assembled by authorities and media in the aftermath of the massacre.
Authorities were examining Saturday the sequence of events that led Adam Lanza to dress in what a law enforcement source said was "black battle fatigues and a military vest," enter Sandy Hook Elementary and begin firing.
The 20 children killed were between the ages of 5 and 10; also killed were six adults, including the principal and a school psychologist, according to parent at the school at the time of the shooting. Two teachers were killed, according to families and friends contacted by CNN.
Adam Lanza was found dead in a classroom, and police recovered three weapons from the scene: a semi-automatic .223 Bushmaster, a Glock and a Sig Sauer, a source with knowledge of the investigation said.
Adam Lanza had no known criminal record, a law enforcement official said.
A member of Lanza's family told investigators that he had a form of autism, according to a law enforcement official, who spoke under condition of anonymity due to the sensitive nature of the investigation.
Acquaintances struggled with fathoming the deadly actions being attributed to someone they had known.
Alex Israel was in the same class at Newtown High School with Adam Lanza, who lived a few houses down from her.
"You could definitely tell he was a genius," Israel told CNN, adding she hadn't talked with him since middle school. "He was really quiet, he kept to himself."
His former bus driver, Marsha Moskowitz, told CNN affiliate WABC that he was "a nice kid, very polite" like his brother.
"It's a shock to even know (the family)," she said. "You can't understand what happened."
A former classmate told CNN affiliate WCBS that Adam Lanza "was just a kid" -- not a troublemaker, not antisocial, not suggesting in any way that he could erupt like this.
"I don't know who would do anything like this," the classmate said, before walking away distraught. "This is unspeakable."
CNN's David Ariosto reported from Connecticut. Michael Martinez wrote and reported from Los Angeles.
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