Adam Lanza in a 2005 photo

He was dark and disturbed, a deeply troubled boy from a wealthy family who unnerved his neighbors and classmates.

Mass murderer Adam Lanza, 20, was a ticking time bomb, people who knew him told the Daily News.

“This was a deeply disturbed kid,” a family insider told the Daily News. “He certainly had major issues. He was subject to outbursts from what I recall.”

Lanza, who friends and officials said suffered from Asperger’s syndrome or a personality disorder, had a tortured mind.

He was socially awkward and at times unstable, but also extraordinarily bright.

“He was smart,” the insider said. “He was like one of these real brainiac computer kind of kids.”

A “longtime” family friend said Lanza had a condition “where he couldn’t feel pain.”

“A few years ago when he was on the baseball team, everyone had to be careful that he didn’t fall because he could get hurt and not feel it,” said the friend. “Adam had a lot of mental problems.”

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Lanza’s strange behavior was well-known among his well-heeled neighbors in leafy Newtown, Conn. His antics irked several residents.

“Adam Lanza has been a weird kid since we were 5 years old,” a neighbor and former classmate named Tim Dalton wrote on Twitter. “As horrible as this was, I can’t say I am surprised . . . Burn in hell, Adam.”

He was also seen as an odd figure at Newtown High School.

Even before that, Lanza walked the halls of his middle school carrying a black briefcase while most students lugged their belongings in backpacks. “That stuck out,” said Tim Lalli, 20, who graduated with Lanza in 2010. “It was different.”

Lalli said Lanza wasn’t a total outcast, but he didn’t speak much.

“Everyone just assumed he was a smart kid and that’s why he didn’t like talking to people all the time,” he said. “He hung out with the smart crowd.”

And he lived in luxury.

NEWTOWN_GUNS_12152012_390

NEW YORK DAILY NEWS

Guns used by Adam Lanza, 20, alleged shooter in Sandy Hook elementary school rampage.

Lanza was living with his devoted mother, Nancy, in the family’s four-bedroom, 3,100-square-foot estate.

Nancy Lanza divorced Adam’s father, Peter, in 2008. Peter Lanza, now a vice president of taxes for GE Energy Financial Services, agreed to annual alimony payments that started at $240,000 and would have reached $298,800 in 2015.

The couple had married on June 6, 1981, in Kingston, N.H. — where Adam Lanza was born — and the divorce hit Peter Lanza hard, his lawyer said.

“He was very upset that he was getting divorced, but he didn’t want to take it out on anybody,” said attorney Gary Oberst.

He said the Lanzas were deeply devoted to their children. In fact, Peter Lanza insisted on handing over more money than his lawyer initially suggested.

“He did more than he had to with the divorce,” said Oberst. “When he came in to consult with me, I said, ‘This is what your obligation is.’ He said, ‘That’s not enough. I want to do more.’ ”

The family insider described the Lanzas as “lovely, very generous people who were very kind to each other during the divorce.”

Peter Lanza was blindsided by news of the shooting. When he drove up to his red-brick home in Stamford, Conn., Friday afternoon, a reporter was waiting outside.

“Is there something I can do for you?” Lanza asked,, according to the Connecticut Post.

When told his address had been linked to the Newtown massacre, his face dropped, he rolled up the window of his blue Mini Cooper and drove into his garage without commenting.

He had arrived home just after a group of cops left. The sight of the officers freaked out neighbor Geralyn Petrafesa.

“Around 3 p.m., I drive by and saw the police wearing vests,” said Petrafesa. “They were approaching the house. I ran home and told my kids to stay in the house. I figured it was connected with what was going on in Newtown.”

The 52-year-old Peter Lanza had only recently moved in with his new wife, Shelley Cudiner, who works in the library at the University of Connecticut.

Peter Lanza also has an academic background. He has served as an adjunct professor at Northeastern University in Boston since 1995 and has taught classes on tax partnerships at Fairfield University, according to the Connecticut Post.

Nancy Lanza, 54, whom Adam murdered inside the home the two shared, reportedly had worked at Sandy Hook Elementary School. But more recently, she was taking care of her son.

“She needed to be home with Adam,” the family insider said.

Nancy was known as a pillar of the community, while neighbors viewed her troubled son as a terror.

“My daughter went to school w/adam lanza,” a former neighbor who identified herself as Beth Israel wrote on Twitter. “We lived 6 houses away. He was troubled for sure for a long time. RIP nancy.”

Early news reports suggested Adam Lanza’s 24-year-old brother, Ryan, had launched the rampage — but Beth Israel believed otherwise.

“It has to be Adam, not Ryan,” she tweeted.

Ryan Lanza, who lives in Hoboken and works at Ernst and Young, didn’t talk about his younger brother while attending Quinnipiac University.

“I knew he had a brother, but I never knew anything more than he existed,” said a college friend.

Ryan Lanza told cops he had not been in touch with his brother since about 2010.

One family friend described Adam Lanza as a gamer who “rarely spoke.”

“He was weird,” said the friend, who asked to remain anonymous. “He was quiet.”

Lanza’s maternal grandmother, Dorothy Hanson, told a Tampa Bay Times reporter she was too shaken to speak.

“(I’m) just trying to absorb it,” said Hanson, 78, who spends winters in a modest mobile home park in Brooksville, Fla.

A friend of Hanson’s said Lanza’s elderly grandmother was “beside herself right now.”

Late Friday night, Peter Lanza’s neighbors said they wondered how he was going to cope with the news that his ex-wife was dead and his youngest son would forever be known as a murderous monster.

“This whole thing is just tragic,” said one neighbor. “I can’t image what he’s dealing with right now.”
- NY Daily News