Nancy Lanza, the 52-year-old mother of Newtown, Conn., school shooter Adam Lanza, kept the trials and setbacks of her home life hidden, say friends.

Now, the secrets kept by Lanza — who divorced in 2009 and had two sons she spoke proudly of — are at the centre of the questions that envelop the town of Newtown, grieving over the slaughter unleashed by her 20-year-old son Adam, who investigators say killed his mother Friday with one of her own guns before killing 26 children and teachers at nearby Sandy Hook Elementary School.

'I heard her as a parent. I always said that I wouldn't want to be in her shoes.'—John Tambascio, co-runs Newtown pizzeria

"Her family life was her family life. She kept it private, when we were together. That was her own thing," said Louise Tambascio, who runs My Place in Newtown, Conn., with her own sons, and became a shopping and dining companion of Nancy Lanza's, who frequented the pizzeria and bar.

Friends had met Lanza's younger son, Adam, who stared down at the floor and didn't speak when she brought him in. They knew he'd switched schools more than once and that she'd tried home schooling him. But while she occasionally expressed concern about his future during evenings at the bar, she never complained about anything.

"I heard her as a parent. I always said that I wouldn't want to be in her shoes. But I thought, 'Wow. She holds it well,"' said Tambascio's son, John.

Divorce left mother with comfortable alimony

Despite those challenges, the trappings of Lanza's life in Newtown were comfortable. When she and then husband Peter Lanza moved there in 1998 from southern New Hampshire, they bought a new 3,100-square-foot colonial set on more than two acres in the Bennett's Farm neighbourhood. Nancy Lanza had previously worked as a stockbroker at John Hancock in Boston and her husband was a successful executive.

When the couple divorced in 2009, his wife got the spacious home and was told by her ex she would never have to work another day in her life, said Marsha Lanza of Crystal Lake, Ill., Lanza's aunt. The split was not acrimonious and Adam spent time with both his mother and father, she said.

Nancy Lanza, received $289,800 US in alimony in 2012. It was to continue until December 2023, with slight increases each year for cost of living.

Adam Lanza, pictured in 2005, has been identified by authorities as the gunman who killed his mother at their home and then killed 26 people, including 20 children, before killing himself at a Newtown, Conn., elementary school.Adam Lanza, pictured in 2005, has been identified by authorities as the gunman who killed his mother at their home and then killed 26 people, including 20 children, before killing himself at a Newtown, Conn., elementary school. (Barbara Frey/Associated Press)

Those who knew Lanza recall her as very generous, often giving money to those she met and doing volunteer work.

When a mutual friend sought a loan from an acquaintance, Jim Leff, and Leff asked for collateral, Lanza intervened.

"Nancy overheard the discussion, and, unblinkingly, told him she'd just write him a cheque then and there," Leff recalled on his blog in a post after Lanza's death.

Mark Tambascio recalled the time Lanza invited him and his brother to attend a Boston Red Sox game, buying them tickets atop the outfield wall known as the Green Monster, and refusing any talk of repayment.

Introduced sons to guns

Lanza also began telling friends that she'd bought guns and had taken up target shooting, John Tambascio said.

All three of the guns that Adam Lanza carried into Sandy Hook Elementary were owned and registered by his mother — a pair of handguns and a .223-calibre Bushmaster rifle, his primary weapon.

Investigators said Sunday that Nancy Lanza visited shooting ranges several times and that her son also visited an area range.

Ginger Colburn, a spokeswoman for the Bureau of Alcohol, Tobacco and Firearms, said it's still not clear whether Nancy Lanza brought her son to the range or whether he ever fired a weapon there.

Four of Nancy Lanza's friends told NBC she absolutely would have kept her guns under lock and key.

Russell Hanoman said she wanted to introduce her sons to the guns to teach them, especially Adam, a sense of responsibility.

“Guns require a lot of respect, and she really tried to instill that responsibility within him, and he took to it," he said. "He loved being careful with them. He made it a source of pride."

Marsha Lanza told the Chicago Sun-Times that Nancy Lanza wanted guns for protection. "She prepared for the worst," she told the newspaper.

"She was a single mom, raising two boys, living alone in a house that's close to the woods," Nancy Lanza's friend, John Tambascio, told CBC News. "I don't see anything odd."

Mom responded to son's episodes at school

But while trips to shooting ranges gave Lanza an outlet, she returned home to the ever-present challenges of raising a son with intractable problems.

At Newtown High School, Adam Lanza was often having crises that only his mother could defuse.

Adam Lanza, third from the right, was once a member of Newtown High School's technology club. Adam Lanza, third from the right, was once a member of Newtown High School's technology club. (Associated Press)

"He would have an episode, and she'd have to return or come to the high school and deal with it," said Richard Novia, the school district's head of security until 2008, who got to know the family because both of Lanza's sons joined the school technology club he chartered.

Novia said Adam Lanza would sometimes withdraw completely "from whatever he was supposed to be doing."

He "could take flight, which I think was the big issue, and it wasn't a rebellious or defiant thing," Novia said. "It was withdrawal."

The club gave the boy a place where he could be more at ease and indulge his interest in computers. His anxieties appeared to ease somewhat, but they never disappeared. When people approached him in the hallways, he would press himself against the wall or walk in a different direction, clutching tight to his black briefcase.

Marsha Lanza described Nancy Lanza as a good mother.

"If he had needed [counselling], she would have gotten it," Marsha Lanza said. "Nancy wasn't one to deny reality."

But friends and neighbours said Lanza never spoke about the difficulties of raising her son. Mostly she noted how smart he was and that she hoped, even with his problems, that he'd find a way to succeed.

Didn't like to leave son alone

Nancy Lanza didn't like to leave her son alone, said a mediator who worked with her and her husband during their divorce, and said that she would care for him as long required.

Marriage therapist Paula Levy recalled Monday that during their 10 two-hour sessions, Nancy and Peter Lanza were respectful of each other and concerned about their son's needs. She said the couple told her their son Adam had been diagnosed with Asperger's syndrome, an autism-spectrum disorder, and they spent considerable time talking about how to provide for his well-being.

The Lanzas were in complete agreement on how to address Adam's needs and said little about the details of his condition, Levy said.

"They worked together about it," said Levy, who recalled the mother and father were equally concerned about their son's needs. "The mom, Nancy, pretty much said she was going to take care of him [Adam] and be there as much as he needed her, even long-term."

The couple agreed Adam would live with his mother and agreed to discuss important decisions, giving final say to Nancy Lanza if they couldn't agree, according to the Sept. 24, 2009 settlement approved by Judge Stanley Novak.

While she would not disclose details of their discussions, Levy wanted to make clear that the Lanzas were loving parents who wanted the best for their son.

'We too are asking why ... we are saddened, but struggling to make sense of what has transpired.'—Peter Lanza, Adam Lanza's father

"These people are soft-spoken, gentle, both of them saying, 'What can we do to help him?"' Levy said.

There is nothing in the divorce court file that discusses the relationship's underlying problems, saying the marriage "has broken down irretrievably and there is no possibility of getting back together."

As part of the divorce, both Nancy and Peter Lanza were ordered to attend a parenting education program, standard practice in Connecticut. The provider, Family Centers Inc., certified that both completed the required sessions.

'We too are asking why,' says gunman's father

Authorities pored over computer, cellphone and credit card records trying to piece together the Lanza family's days leading up to the shooting.

Peter Lanza, in a statement this weekend, said that like everyone else, he could not comprehend what had unfolded.

"We too are asking why," he said. "We have co-operated fully with law enforcement and will continue to do so. Like so many of you, we are saddened, but struggling to make sense of what has transpired."

With files from CBC News