Joe Raedle / Getty Images file

A Bushmaster XM-15 .223-caliber rifle, the type of weapon that authorities say Sandy Hook Elementary School gunman Adam Lanza used to inflict most of the fatalities.

NEWTOWN, Conn. -- The three guns carried by the gunman in the bloody Sandy Hook Elementary School shooting were all purchased by his mother since 2010, law enforcement sources told NBC News on Tuesday.

The sources, who spoke on condition of anonymity, said that Nancy Lanza, who friends described as a gun enthusiast, purchased the weapons legally over a three-year period, beginning in 2010 with a Bushmaster XM-15  .223-caliber semi-automatic assault-style rifle -- the weapon that authorities say 20-year-old Adam Lanza used to mow down the victims in Friday’s rampage. She then bought a 9 mm Sig Sauer pistol in 2011, followed by a 10 mm Glock pistol in January 2012. Both weapons also were in Adam Lanza’s possession during his attack on the school, and he used the latter to kill himself when police arrived on the scene, authorities say.

Adam Lanza killed his 52-year-old mother at the home they shared before driving to the school and forcing his way in. Once inside, he killed 20 children and six adults before committing suicide, authorities say.

In addition to the weapons recovered at the crime scene, including a shotgun recovered from the trunk of the car the gunman drove to the school, the Associated Press reported that authorities investigating the shooting recovered three other weapons -- a Henry repeating rifle, an Enfield rifle and a shotgun. It was not clear where those weapons were found.

Meantime, the sources said investigators have found no evidence that Adam Lanza visited area shooting ranges in the last six months.

Federal agents have been examining records at the ranges to see if Adam Lanza had been practicing his marksmanship in the months leading up to the attack, which could indicate that he had planned the massacre well in advance of carrying it out.   

Michael Isikoff is NBC News national investigative correspondent; NBC News’ Justice Correspondent Pete Williams also contributed to this report.

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NEWTOWN, Conn. -- New details about the private lives of Sandy Hook gunman Adam Lanza and his mother, Nancy, emerged Monday, including details of a 2009 divorce settlement that resulted in annual payments to her of nearly $300,000 and gave her ultimate authority to make all decisions on behalf of her troubled son.

Handout / NBC News

Adam Lanza in an undated photo.

While the divorce was granted on the grounds that "the marriage has broken down irretrievably," the parting of the ways between Nancy Lanza and her ex-husband Peter was relatively amicable, according to records obtained by NBC News.

There was no custody dispute over Adam, then a teenager, when the couple split. Peter Lanza, a vice president for taxes at GE Energy and Financial Services, agreed to solely finance the cost of his two sons' college and graduate school education and to provide a car for Adam if he should want one. He also maintained joint legal custody with visitation rights and vacations with Adam. (GE is a minority owner in NBCUniversal.)

There was a check mark in a "limited contest" box on one form -- meaning there appeared to be some financial or property disputes -– but the final settlement reflected no obvious friction.

Nancy Lanza got the Newtown, Conn., house, which she was required to sell or refinance by February 2011 so he would no longer be liable, and the couple kept their own jewelry, and divided photos, personal property -- even season tickets to Boston Red Sox games.

Friends say that Nancy Lanza, a former financial trader, had not been working in recent years. The terms of the settlement could explain why: She received $289,800 in alimony in 2012,which was to increase each year to reach $298,000 in 2015.

But sources close to the family tell NBC News that beneath the apparently cordial separation, which dated to 2001, animosity was growing between the father and his youngest son.

By 2010, Peter Lanza was dating a new woman, whom he later married, according to the sources, who spoke on condition of anonymity, and Adam Lanza cut off all communication with his father. Peter tried to see Adam, but his son refused, they said.

Authorities say Nancy Lanza was the first victim in Friday’s murderous rampage, slain by multiple gunshots in her Newtown home shortly before Adam Lanza, 20, drove to Sandy Hook Elementary School and blasted his way in. By the time police responded, 20 young children, six adults and Adam Lanza were all dead from gunshot wounds, his being self-inflicted.

Friends of Nancy Lanza in Newtown on Monday shed new light on Adam Lanza’s at-times strange behavior in the years before the shooting, but said she did not indicate that it had changed in recent months.

Obtained by NBC News

Nancy Lanza in a Facebook photo provided by a friend.

Ellen Adriani and Russell Hanoman, both of whom said they were close friends of Nancy Lanza’s, said the 52-year-old single mother was devoted to her youngest son, whom they described as intelligent, mild-mannered and socially awkward. He also had an aversion to human contact, they said.

Hanoman, who said he had met Adam on several occasions, recalled him as a “very mild-mannered” young man who was interested in technology and engineering and liked to maintain his distance from other people.

“I remember when I first met him, he deliberately stood maybe 6 feet away from me and took three exaggerated steps toward me … stuck out his hand, shook (mine) … put it back and (took) three exaggerated steps back.”

Adriani, who never met Adam, said Nancy Lanza told her of a time when Adam was ill while he was in high school and didn’t want her to enter his bedroom.

“But yet he still wanted Nancy there for him, so she camped out all night outside his bedroom door,” she said. “Periodically through the evening, he would ask her, ‘Are you there? Are you still there?’ and she’d be, ‘I’m here. I’m here.’ So he needed to have that security that she was there but not in his space.”

Hanoman also remembered Nancy Lanza as a devoted mother.

“Everything that she did in life … was devoted to making sure that he was taken care of,” he said.

Adam Lanza also was “an organic vegan” with a conservative worldview, he said.

“He was actually politically aware for a teenager,” he said. “… He was always very free-market economics and capitalism, as I think most people are in this country.”

He also was interested in target shooting, sometimes accompanying his mother to local shooting ranges to practice. (Federal agents investigating the school massacre said Monday that they have found evidence that Adam Lanza visited more than one range and "engaged in shooting activities."  And they say they know that he visited some ranges with his mother.)

In addition to his technological and weapons prowess, Adam Lanza was an excellent dancer – at least within the confines of the Dance Dance Revolution video game.

“It’s an arcade game as well as on the home systems where you basically dance around to a pattern on the screen,” Hanoman said. “And he was extremely good at it. He would often accumulate an audience of people around watching him…. (But) because it’s a two-player game … if anyone tried to come on the platform with him, no matter what he was doing, he would just turn around and walk out of the arcade.”

Despite such anti-social behavior, Hanoman said that mother and son had over the past several years looked at a number of colleges where Adam Lanza might be able to make a fresh beginning.

“He wanted to go back to school, so they were looking at colleges all over the country, looking for an ideal environment for him,” he said. “… He wanted to become more socialized. He didn’t want to stay trapped in his home the rest of his life.”

NBC News Justice Correspondent Pete Williams, Today Investigative Correspondent Jeff Rossen and Today Producer Robert Powell contributed to this report.

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