Update: The focus now shifts to the mother, the first casualty of her son's murderous rampage, who was a "big, big gun fan" as the NYT explains, and who went target shooting with her children, one of whom had Asperger's.
From the NYT:
She was “a big, big gun fan” who went target shooting with her children, according to friends. She enjoyed craft beers, jazz and landscaping. She was generous to strangers, but also high-strung, as if she were holding herself together.
Nancy Lanza was the first victim in a massacre carried out on Friday by her son Adam Lanza, 20, who shot her dead with a gun apparently drawn from her own collection, then drove her car to Sandy Hook Elementary School, where he killed 26 people, 20 of them small children, officials said.
At craft beer tastings on Tuesday evenings, he recalled, she liked to talk about her gun collection.
“She had several different guns,” he said. “I don’t know how many. She would go target shooting with her kids.”
Law enforcement officials said they believed that the guns were acquired lawfully and registered.
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She was “a big, big gun fan,” he added on his Web site.
Read on here
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As we reported last night, buried inside the NYT biopic of Newtown shooter Adam Lanza was arguably one of the most important missing pieces in the story, at least so far, which could provide clues into partially explaining yesterday's tragic loss of young life, namely that the 20 year old man suffered from Asperger Syndrome, a high-functioning form of autism (two conditions which are being merged in the upcoming update of the Diagnostic and Statistical Manual (DSM-5) manual of mental disorders), which has been traditionally associated with social communication difficulties, including flat affect, and one which in some clinical studies has been shown to have a causal link to violence. In other words, in addition to the surge in the debate over national gun control and access limitations (ignoring that the perpetrator of the biggest school mass murder in US history - the Bath School disaster - used openly purchased dynamite and no guns, also ignoring that in the US there are roughly 300 million firearms), perhaps there should also be a broad discussion as to the risks of social misadoption of children with autism and other social and behavioral disorders.
He was an honors student who lived in a prosperous neighborhood with his mother, a well-liked woman who enjoyed hosting dice games and decorating the house for the holidays.
Now Adam Lanza is suspected of killing his mother and then gunning down more than two dozen people, 20 of them children, at a Connecticut grade school before taking his own life.
The 20-year-old may have suffered from a personality disorder, law enforcement officials said.
The New York Times reported Saturday morning that several people told the newspaper that Lanza had Asperger’s syndrome, a high-functioning form of autism.
The Times reported Lanza did not have a Facebook page and did not pose for a high school yearbook picture.
He was described as socially awkward and was known in high school as “intelligent, but nervous and fidgety, spitting his words out, as if having to speak up were painful.”
Investigators were trying to learn as much as possible about Lanza and questioned his older brother, who is not believed to have any involvement in the rampage.
Lanza killed his mother at their home before driving her car to Sandy Hook Elementary School and — armed with at least two handguns — carried out the massacre, officials said.
A third weapon, a .223-caliber rifle, was found in the car, and more guns were found inside the school.
So far, authorities have not spoken publicly of any possible motive. Witnesses said the shooter didn’t utter a word.
Catherine Urso, who was attending a vigil Friday evening in Newtown, Conn., said her college-age son knew the killer and remembered him for his alternative style.
“He just said he was very thin, very remote and was one of the goths,” she said.
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Adam Lanza’s older brother, 24-year-old Ryan Lanza of Hoboken, N.J., was being questioned, a law enforcement official said. He told authorities that his brother was believed to suffer from a personality disorder, the official said, speaking on condition of anonymity because he was not authorized to speak on the record about the unfolding investigation.
The official did not elaborate, and it was unclear exactly what type of disorder he might have had.
Ryan Lanza had been extremely cooperative and was not under arrest or in custody, but investigators were still searching his computers and phone records. Ryan Lanza told law enforcement he had not been in touch with his brother since about 2010.
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Adam Lanza attended Newtown High School, and several local news clippings from recent years mention his name among the school’s honor roll students.
And while much needed insight into the shooter's abnormal mental state is critical before passing judgment, the reality is that Lanza - who may well have been mentally disturbed - should certainly not have had access to the arsenal of weapons he ultimately used in perpetrating yesterday's tragedy. The much debated question, of course, that is already emerging is whose responsibility is it to limit such access: that of the individual, that of the closest family members, or that of the state, and if it is the latter, then the question becomes one of practical enforceability in a country where the second amendment is deeply engrained in the popular psychology, and where there are nearly as many guns as people.
Some more facts and figures - without opinions - on US weapons from justfacts.com
This research is based upon the most recent available data in 2010. Facts from earlier years are cited based upon availability and relevance, not to slant results by singling out specific years that are different from others. Likewise, data associated with the effects of gun control laws in various geographical areas represent random, demographically diverse places in which such data is available.
Many aspects of the gun control issue are best measured and sometimes can only be measured through surveys, but the accuracy of such surveys depends upon respondents providing truthful answers to questions that are sometimes controversial and potentially incriminating. Thus, Just Facts uses such data critically, citing the best-designed surveys we find, detailing their inner workings in our footnotes, and using the most cautious plausible interpretations of the results.
Particularly, when statistics are involved, the determination of what constitutes a credible fact (and what does not) can contain elements of personal subjectivity. It is our mission to minimize subjective information and to provide highly factual content. Therefore, we are taking the additional step of providing readers with four examples to illustrate the type of material that was excluded because it did not meet Just Facts' Standards of Credibility.
Firearms are generally classified into three broad types: (1) handguns, (2) rifles, and (3) shotguns. Rifles and shotguns are both considered "long guns."
A semi-automatic firearm fires one bullet each time the trigger is pulled and automatically loads another bullet for the next pull of the trigger. A fully automatic firearm (sometimes called a "machine gun") fires multiple bullets with the single pull of the trigger.
As of 2009, the United States has a population of 307 million people.
Based on production data from firearm manufacturers, there are roughly 300 million firearms owned by civilians in the United States as of 2010. Of these, about 100 million are handguns.
Based upon surveys, the following are estimates of private firearm ownership in the U.S. as of 2010:
|Households With a Gun||Adults Owning a Gun||Adults Owning a Handgun|
|Number||47-53 million||70-80 million||40-45 million|
A 2005 nationwide Gallup poll of 1,012 adults found the following levels of firearm ownership:
In the same poll, gun owners stated they own firearms for the following reasons:
|Protection Against Crime||67%|
Crime and Self-Defense
Roughly 16,272 murders were committed in the United States during 2008. Of these, about 10,886 or 67% were committed with firearms.
A 1993 nationwide survey of 4,977 households found that over the previous five years, at least 0.5% of households had members who had used a gun for defense during a situation in which they thought someone "almost certainly would have been killed" if they "had not used a gun for protection." Applied to the U.S. population, this amounts to 162,000 such incidents per year. This figure excludes all "military service, police work, or work as a security guard."
Based on survey data from the U.S. Department of Justice, roughly 5,340,000 violent crimes were committed in the United States during 2008. These include simple/aggravated assaults, robberies, sexual assaults, rapes, and murders.   Of these, about 436,000 or 8% were committed by offenders visibly armed with a gun.
Based on survey data from a 2000 study published in the Journal of Quantitative Criminology, U.S. civilians use guns to defend themselves and others from crime at least 989,883 times per year.
A 1993 nationwide survey of 4,977 households found that over the previous five years, at least 3.5% of households had members who had used a gun "for self-protection or for the protection of property at home, work, or elsewhere." Applied to the U.S. population, this amounts to 1,029,615 such incidents per year. This figure excludes all "military service, police work, or work as a security guard."
A 1994 survey conducted by the U.S. Centers for Disease Control and Prevention found that Americans use guns to frighten away intruders who are breaking into their homes about 498,000 times per year.
A 1982 survey of male felons in 11 state prisons dispersed across the U.S. found:
• 34% had been "scared off, shot at, wounded, or captured by an armed victim"
• 40% had decided not to commit a crime because they "knew or believed that the victim was carrying a gun"
• 69% personally knew other criminals who had been "scared off, shot at, wounded, or captured by an armed victim"
Click here to see why the following commonly cited statistic does not meet Just Facts' Standards of Credibility: "In homes with guns, the homicide of a household member is almost 3 times more likely to occur than in homes without guns."
Vulnerability to Violent Crime
At the current homicide rate, roughly one in every 240 Americans will be murdered.
A U.S. Justice Department study based on crime data from 1974-1985 found:
• 42% of Americans will be the victim of a completed violent crime (assault, robbery, rape) in the course of their lives
• 83% of Americans will be the victim of an attempted or completed violent crime
• 52% of Americans will be the victim of an attempted or completed violent crime more than once
A 1997 survey of more than 18,000 prison inmates found that among those serving time for a violent crime, "30% of State offenders and 35% of Federal offenders carried a firearm when committing the crime."
Right-to-carry laws permit individuals who meet certain "minimally restrictive" criteria (such as completion of a background check and gun safety course) to carry concealed firearms in most public places. Concealed carry holders must also meet the minimum federal requirements for gun ownership as detailed above.
Each state has its own laws regarding right-to-carry and generally falls into one of three main categories:
1) "shall-issue" states, where concealed carry permits are issued to all qualified applicants
2) "may-issue" states, where applicants must often present a reason for carrying a firearm to an issuing authority, who then decides based on his or her discretion whether the applicant will receive a permit
3) "no-issue" states, where concealed carry is generally forbidden
As of January 2012:
40 states are shall-issue:
|New Hampshire||New Mexico||North Carolina||North Dakota|
|Rhode Island||South Carolina||South Dakota||Tennessee|
9 states are may-issue:
In 2007, there were 613 fatal firearm accidents in the United States, constituting 0.5% of 123,706 fatal accidents that year.
Fatal firearm accidents in 2007 by age groups:
|Age Group||Fatal Firearm Accidents|
|Raw number||Portion of fatal accidents|
from all causes
In 2007, there were roughly 15,698 emergency room visits for non-fatal firearm accidents, constituting 0.05% of 27.7 million emergency room visits for non-fatal accidents that year.
These emergency room visits for non-fatal firearm accidents resulted in 5,045 hospitalizations, constituting 0.4% of 1.4 million non-fatal accident hospitalizations that year.
Criminal Justice System
Nationwide in 2008, law enforcement agencies reported that 55% of aggravated assaults, 27% of robberies, 40% of rapes, and 64% of murders that were reported to police resulted in an alleged offender being arrested and turned over for prosecution. 
Currently, for every 12 aggravated assaults, robberies, sexual assaults, rapes, and murders committed in the United States, approximately one person is sentenced to prison for committing such a crime.  
A 2002 U.S. Justice Department study of 272,111 felons released from state prisons in 1994 found that within three years of their release:
• at least 67.5% had been arrested for committing a new offense
• at least 21.6% had been arrested for committing a new violent offense
• these former inmates had been charged with committing at least 2,871 new homicides, 2,444 new rapes, 3,151 other new sexual assaults, 2,362 new kidnappings, 21,245 new robberies, 54,604 new assaults, and 13,854 other new violent crimes
Of 1,662 murders committed in New York City during 2003-2005, more than 90% were committed by people with criminal records.
In 1976, the Washington, D.C. City Council passed a law generally prohibiting residents from possessing handguns and requiring that all firearms in private homes be (1) kept unloaded and (2) rendered temporally inoperable via disassembly or installation of a trigger lock. The law became operative on Sept. 24, 1976. 
On June 26, 2008, the U.S. Supreme Court, in a 5-4 ruling, struck down this law as unconstitutional.
During the years in which the D.C. handgun ban and trigger lock law was in effect, the Washington, D.C. murder rate averaged 73% higher than it was at the outset of the law, while the U.S. murder rate averaged 11% lower.
In 1920, Britain passed a law requiring civilians to obtain a certificate from their district police chief in order to purchase or possess any firearm except a shotgun. To obtain this certificate, the applicant had to pay a fee, and the chief of police had to be "satisfied" that the applicant had "good reason for requiring such a certificate" and did not pose a "danger to the public safety or to the peace." The certificate had to specify the types and quantities of firearms and ammunition that the applicant could purchase and keep.
In 1968, Britain made the 1920 law stricter by requiring civilians to obtain a certificate from their district police chief in order to purchase or possess a shotgun. This law also required that firearm certificates specify the identification numbers ("if known") of all firearms and shotguns owned by the applicant.
In 1997, Britain passed a law requiring civilians to surrender almost all privately owned handguns to the police. More than 162,000 handguns and 1.5 million pounds of ammunition were "compulsorily surrendered" by February 1998. Using "records of firearms held on firearms certificates," police accounted for all but fewer than eight of all legally owned handguns in England, Scotland, and Wales.
† Homicide data is published according to the years in which the police initially reported the offenses as homicides, which are not always the same years in which the incidents took place.
‡ Large anomalies unrelated to guns:
2000: 58 Chinese people suffocated to death in a shipping container en route to the UK
2002: 172 homicides reported when Dr. Harold Shipman was exposed for killing his patients
2003: 20 cockle pickers drowned resulting in manslaughter charges
2005: 52 people were killed in the July 7th London subway/bus bombings
Not counting the above-listed anomalies, the homicide rate in England and Wales has averaged 52% higher since the outset of the 1968 gun control law and 15% higher since the outset of the 1997 handgun ban.
In 1982, the city of Chicago instituted a ban on handguns. This ban barred civilians from possessing handguns except for those registered with the city government prior to enactment of the law. The law also specified that such handguns had to be re-registered every two years or owners would forfeit their right to possess them. In 1994, the law was amended to require annual re-registration.  
In the wake of Chicago's handgun ban, at least five suburbs surrounding Chicago instituted similar handgun bans. When the Supreme Court overturned the District of Columbia's handgun ban in June 2008, at least four of these suburbs repealed their bans.    
In June 2010, the U.S. Supreme Court ruled (5-4) that Chicago's ban is unconstitutional.
Since the outset of the Chicago handgun ban, the Chicago murder rate has averaged 17% lower than it was before the law took effect, while the U.S. murder rate has averaged 25% lower.
Since the outset of the Chicago handgun ban, the percentage of Chicago murders committed with handguns has averaged about 40% higher than it was before the law took effect.
In 2005, 96% of the firearm murder victims in Chicago were killed with handguns.
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Much more here