Adam Peter Lanza (April 22, 1992 â December 14, 2012) was an American mass murderer responsible for the Sandy Hook Elementary School shooting, one of the deadliest deadliest mass shootings in the US. On December 14, 2012, he fatally shot his mother, Nancy Lanza, at their home in Newtown, Connecticut, before driving to Sandy Hook Elementary School, where he killed 20 children between the ages of six and seven, and six adult staff members. He then killed himself as law enforcement arrived at the school.
Lanza was born in Exeter, New Hampshire, and grew up in Newtown, Connecticut, where he was raised primarily by his mother following his parents' divorce in 2008. From an early age, he was diagnosed with a number of developmental and psychiatric conditions, including Asperger syndrome, sensory processing disorder, and obsessive-compulsive disorder. He was described by those who knew him as highly intelligent but profoundly withdrawn. He struggled throughout his childhood and adolescence with social interaction and emotional regulation.
As a teenager, Lanza became increasingly isolated and stopped attending school. His anxiety led to him being placed on homebound status, where he received instruction at home rather than attending classes. His mother declined treatments recommended by the Yale Child Study Center, preferring to accommodate his preferences rather than forcing him to adapt to social environments and improving his mental health. Lanza developed an intense preoccupation with mass violence, compiling extensive research on prior shootings and maintaining spreadsheets documenting past attacks. Lanza withdrew from social contact almost entirely in the years before the shooting.
Lanza had access to an arsenal of legally purchased firearms belonging to his mother, who was an avid gun enthusiast. Severe mental illness, social isolation, and access to weapons were all identified as contributing factors to the shooting by Connecticut state authorities and the Office of the Child Advocate. The Sandy Hook shooting led to renewed legislative efforts on gun control at both the state and federal level. Nancy Lanza's role in facilitating her son's access to firearms became a significant point of public and legal scrutiny.
Adam Peter Lanza was born in Exeter, New Hampshire, on April 22, 1992, to Peter and Nancy Lanza ( Champion). Lanza had an older brother named Ryan. Early evaluations found "significant delay in social-personal development" and difficulty in being understood by others. By preschool, he was diagnosed with sensory processing disorder, which made typical sights, sounds, and touch physically overwhelming for him. Lanza did not speak until he was three years old. By age five, he exhibited obsessive-compulsive behaviors such as excessive hand washing and a rigid need for routine. In early adolescence, he was diagnosed with Asperger's syndrome, a form of autism, which contributed to his extreme shyness and social awkwardness.
While teachers noted he was academically bright, he required an Individualized Education Program (IEP) for speech and social-emotional support from preschool onward. He attended Sandy Hook Elementary School for four and a half years. Nancy's house was located five miles away from Sandy Hook Elementary School. His father, Peter, described him as a "normal little weird kid" who enjoyed playing with Legos and inventing board games.
Lanza's challenges intensified after fourth grade. He started attending Newtown Middle School in 2004. The transition to middle schoolâÂÂwhere he had to change classrooms and navigate noisy hallwaysâÂÂwas physically and emotionally overwhelming for him. His mother reported that he experienced intense anxiety during this period. She told friends that her son started getting upset in middle school because of frequent classroom changes during the day. The movement and noise were too stimulating and made him anxious. At one point, his anxiety was so intense that she took him to the emergency room at Danbury Hospital. Because of the smaller class sizes, his mother moved him to a parochial school, St. Rose of Lima. According to a classmate at St. Rose of Lima, he entered "late in the school year", and he left in June 2005. By 8th grade, his anxiety was so severe that he was placed on homebound status, receiving instruction at home rather than in a classroom.
Lanza briefly attended Newtown High School, where he was active in a technology club but remained socially isolated. Students and teachers who knew him in high school described Lanza as "intelligent but nervous and fidgety". He avoided attracting attention and was uncomfortable socializing. He was not known to have had any close friends in school. The intense anxiety Lanza experienced at the time suggests his autism might have been exacerbated by the hormonal shifts of adolescence.
Lanza was named to the honor roll in 2007.
At age 16, while still technically a high school student, Lanza enrolled in classes at Western Connecticut State University. He maintained a 3.26 GPA. He earned an A in computer programming, an A- in American history, and a B in macroeconomics. His mother eventually withdrew him from high school to finish his credits early through a mix of tutoring and independent study. He earned a GED at age 16. The Office of the Child Advocate later concluded that his schools often focused on managing his symptoms rather than addressing the underlying social-emotional deficits.
Lanza's parents divorced in September 2009 after Nancy filed for divorce in November 2008, citing "irreconcilable differences". The couple had already been separated before the filing, with Peter living in an apartment in downtown Stamford while Nancy remained in the family home. Observers and court documents described the split as relatively amicable, with no public disputes over property or parenting. Peter agreed to a substantial alimony arrangement that provided Nancy with nearly $290,000 annually by 2012. He also committed to paying for both sons' college and graduate educations. They shared joint legal custody of Adam, who was 17 at the time of the finalization, though he lived primarily with Nancy. The agreement gave Nancy the final decision-making power if they could not agree on issues regarding Lanza. The divorce settlement effectively created a symbiotic environment that allowed Adam to withdraw completely from the world.
Nancy became a stay-at-home mother shortly after Adam was born. He had access to the guns used in the shooting through his mother, who was described as a "gun enthusiast who owned at least a dozen firearms". She often took her two sons to a local shooting range, where they learned to shoot. Lanza's father, Peter, has said that he does not believe Nancy feared Adam. She did not confide any fear of him to her sister or to her best friend, slept with her bedroom door unlocked, and kept guns in the house.
Adam struggled with showing basic emotions and would be coached by his mother when he was young. Adam was involved in a school play during his childhood, his mother had written to a friend "Adam has taken it very seriously, even practicing facial expressions in the mirror!" The state's attorney report on the shooting states that when Nancy asked Adam whether he would feel sad if anything happened to her, he replied "No."
Following his departure from community college in 2010, Lanza became a complete recluse. He lived in his mother's home, where he used black trash bags to black out the windows of his bedroom. He communicated with his mother, Nancy, almost exclusively via email, despite living together. In the final months, he often refused to leave his room or engage with her at all. He abruptly cut off all contact with his father, Peter, in 2010 and was estranged from his older brother, Ryan.
While living in New Hampshire at the time, Lanza exhibited developmental challenges before the age of three. These included communication and sensory difficulties, socialization delays, and repetitive behaviors. He was seen by the New Hampshire Birth to Three intervention program and referred to special education preschool services. Once at elementary school, he was diagnosed with a sensory-integration disorder. The sensory-processing disorder does not have official status by the medical community as a formal diagnosis but is a common characteristic of autism. His anxiety affected his ability to attend school and in 8th grade he was placed on "homebound" status, which is reserved for children who are too disabled, even with supports and accommodations, to attend school.
When he was 13, Lanza was diagnosed with Asperger syndrome by a psychiatrist, Paul Fox. When he was 14, his parents took him to Yale University's Child Study Center, where he was also diagnosed with obsessive-compulsive disorder (OCD), depression and anxiety. He frequently washed his hands and changed his socks 20 times a day, to the point where his mother did three loads of laundry a day. He also sometimes went through a box of tissues in a day because he could not touch a doorknob with his bare hand.
Lanza received treatment from Robert King, who advised implementing comprehensive support, and Kathleen Koenig, a colleague at the Yale Child Study Center, prescribed the antidepressant Celexa. Lanza took the medication for three days. His mother Nancy reported: "On the third morning he complained of dizziness. By that afternoon he was disoriented, his speech was disjointed, he couldn't even figure out how to open his cereal box. He was sweating profusely ... it was actually dripping off his hands. He said he couldn't think ... He was practically vegetative." He never took the medication again. A report from the Office of the Child Advocate found that "Yale's recommendations for extensive special education supports, ongoing expert consultation, and rigorous therapeutic supports embedded into (Lanza's) daily life went largely unheeded."
During a 2013 interview, Peter Lanza expressed his suspicion that his son might have had undiagnosed schizophrenia alongside his other conditions. Lanza said that family members may have overlooked signs of the onset of schizophrenia and psychotic behavior in his son's adolescence, mistakenly attributing his peculiar behavior and growing isolation to Asperger syndrome. Because of concerns that published accounts of Lanza's autism could result in a backlash against others with the condition, autism advocates campaigned to clarify that autism is a brain-related developmental disorder rather than a mental illness. The aggression displayed by Lanza in the shooting is typically not observed in the autistic population and none of the psychiatrists he consulted identified concerning indications of violence in his demeanor.
Lanza appears to have had no contact with mental health providers after 2006. The report from the Office of the Child Advocate stated: "In the course of Lanza's entire life, minimal mental health evaluation and treatment (in relation to his apparent need) was obtained. Of the couple of providers that saw him, only oneâÂÂthe Yale Child Study CenterâÂÂseemed to appreciate the gravity of (his) presentation, his need for extensive mental health and special education supports, and the critical need for medication to ease his obsessive-compulsive symptoms."
Lanza was 6 feet tall and weighed only 112 pounds at the time of his death. Medical experts believe this severe malnutrition caused cognitive impairment and brain damage. He received no psychiatric treatment or medication after 2008, despite being impaired by anxiety and obsessiveâÂÂcompulsive disorder (OCD). In early 2016, officials confirmed that a 25-second video of a man playing Dance Dance Revolution was Lanza. In Connecticut's final report on Lanza, it was stated that he was obsessed with the game and would play at a Connecticut theater for up to 10 hours a day every weekend.
Lanza's online activity was a primary focus for investigators, as it provided the only real window into his deteriorating mental state and his obsession with mass murder. In his final years, his life was almost entirely lived through his computer.
Lanza never permitted others to access his bedroom, not even his own mother. Lanza had also taped black plastic garbage bags over the windows in his bedroom in order to block out sunlight. He had cut off contact with both his father and brother in the two years before the shooting and at one point communicated with his mother, who lived in the same house, only by email. A document titled "Selfish", describing Lanza's belief in the inherent selfishness of women, was found on his computer after his death.
Investigation findings revealed Lanza had a keen interest in mass shootings, such as the Columbine High School massacre. Adam Lanza made a spreadsheet with detailed information on mass shooters and mass shooting incidents, along with making Tumblr accounts named after school shooters. In his room, investigators uncovered clippings, including a story from The New York Times detailing an incident in 1891 where a man shot at schoolchildren. His computer contained two videos of gunshot suicides, movies that showed school shootings, and two pictures of Lanza pointing guns at his own head.
Lanza had an account on a forum titled "Super Columbine Massacre RPG", which discusses the video game of the same name and other mass shootings. Lanza used the username "Smiggles". Lanza's posts on Tumblr and the Super Columbine Massacre RPG! forum is seen as a clear indicator by investigators about Lanza's fascination with Columbine and other mass shooting incidents. In one post on the forum, Lanza describes having a dream about Columbine while he was asleep. In another, he wrote: "I'm still waiting for a mass shooter who eschews 9mm pistols and instead buys an AK-47 pistol, 30 30-round magazines, and 1000 hollow points". Other users on the forum accused Lanza of pedophilia after he posted "disturbing sexualized ideas about children", including eliminating the age of consent.
Lanza had posted writings related to the 2011 Norway attacks perpetrated by Anders Behring Breivik, citing his mass murder as "impressive", and writing that he "finally outdid Woo Bum-kon", referring to how South Korean policeman Woo's spree killing had been the deadliest rampage to date when Breivik's attacks occurred. He also contrasted Breivik to American-Israeli mass murderer Baruch Goldstein.
Federal Bureau of Investigation (FBI) documents released in 2017 revealed that a man warned the Newtown Police Department in 2008âÂÂfour years before the massacreâÂÂthat Lanza was planning to kill his mother and children at Sandy Hook Elementary School. Authorities discovered a massive, 7-by-4-foot spreadsheet on his computer that documented hundreds of mass murders dating back to the 1700s. It contained 17 categories, including weapon types, casualty counts, and the death of the perpetrator. Some investigators believe he was studying these cases to maximize his own lethality or to compete for a high ranking on his own list. While he reportedly told an online contact in the summer of 2012 that he "no longer cared about mass killer rankings", investigators concluded this was a diversion from his own active preparations.
At age 10, Lanza co-authored the Big Book of Granny, which contained graphic descriptions of violence against children, indicating a very early preoccupation that went largely unaddressed. In the seventh grade, Lanza wrote an essay titled "Battles, Destruction and War" that caused a teacher to believe he was consumed by "feelings of rage, hate and (at least unconscious) murderous impulses". The writing was described by the educator as so graphic and violent that it could not be shared with the rest of the class.
In November 2014, a report from the Office of the Child Advocate in Connecticut suggested that Lanza could have been dealing with anorexia nervosa. The authors stated that "Anorexia may lead to cognitive impairment, and the combination of anorexia with an autism spectrum disorder and OCD likely heightened Lanza's risk of suicide." They also noted that at the time of his death, Lanza "was anorexic (he was six feet tall (183 cm) and weighed 112 pounds (51 kg)), to the point of malnutrition and resultant brain damage."
He lived in near-complete isolation within his room, dedicating his time to browsing the Internet and playing World of Warcraft and other video games. The report stated that he "descended" into a world where his only communication with the outside world was with members of a cyber-community, "a small community of individuals that shared his dark and obsessive interest in mass murder".
In the weeks leading up to the shooting, Lanza's mother was contemplating moving him to a different town. She planned to purchase a recreational vehicle for him to stay in so that potential purchasers could see the house without disturbing him. The Report of the Child Advocate stated that:
James Knoll, a forensic psychiatrist at SUNY Upstate Medical University, was consulted about what motivated Lanza to kill. Knoll states that Lanza's final act conveyed a distinct message: "I carry profound hurtâÂÂI'll go ballistic and transfer it onto you."
On the morning before the shooting, Lanza removed the hard drive from his computer and intentionally destroyed it with a hammer or screwdriver, making it difficult for investigators to recover its data. Sometime before 9:30a.m. EST on December 14, 2012, Lanza fatally shot his mother Nancy, with a .22-caliber Savage Mark II rifle at their Newtown home. Investigators later found her body in her bed, clad in pajamas, with four gunshot wounds to her head. Lanza then drove to Sandy Hook Elementary School in his mother's car. Shortly after 9:35a.m., armed with his mother's Bushmaster XM15-E2S rifle and ten magazines with 30 rounds each, Lanza shot his way through a glass panel next to the school's locked front entrance doors. He was wearing black clothing, yellow earplugs, sunglasses, a black hat, and an olive green utility vest. Initial reports that he was wearing body armor were incorrect. Some of those present heard the initial shots on the school intercom system, which was being used for morning announcements. The police heard the final shot at 9:40:03a.m. They believed that it was Lanza shooting himself in the lower rear portion of his head with the Glock 20SF in classroom 10. Lanza's body was found wearing a pale green pocket vest over a black polo shirt over a black T-shirt, along with black sneakers, black fingerless gloves, black socks, and a black canvas belt. Other objects found in the vicinity of Lanza included a black boonie hat and thin frame sunglasses. The Glock was found, apparently jammed, near Lanza, and the rifle was found several feet away from him. A 9mm SIG Sauer P226, which had not been fired during the incident, was also found on Lanza.
Lanza shot all but two of his victims multiple times. Most of the shooting took place in two first-grade classrooms near the entrance of the school. The students among the victims totaled eight boys and twelve girls, all either six or seven years old, and the six adults were all women who worked at the school. Eighteen children were pronounced dead at the school and two were pronounced dead at Danbury Hospital.
While official investigations concluded that Lanza's specific motive may never be fully known, they identified a cascade of events and several psychological factors that likely contributed to his decision. Lanza lived in almost total isolation in the years preceding the shooting, eventually spending his days in a room with blacked-out windows. In online messages, he expressed an intense "scorn for humanity" and a cynical, negative view of the world. Experts suggest he suffered from narcissism and solipsism, a state where he perceived other people as "cardboard cutouts" without real value, which removed any moral constraint against killing them.
He was obsessed with the Columbine High School massacre and Anders Behring Breivik, the perpetrator of the 2011 Norway attacks. In messages to a fellow gamer, he wrote, "I incessantly have nothing other than scorn for humanity". Federal Bureau of Investigation (FBI) documents revealed he wrote a screenplay titled Lovebound regarding a relationship between a man and a young boy and expressed views that child-adult relationships could be beneficial. Just before the shooting, Lanza's mother reportedly planned to move out of Newtown to find better support for him. One theory suggests Lanza may have targeted the school because of an extreme anxiety-driven resistance to leaving his childhood home and familiar environment.
An online acquaintance told the Federal Bureau of Investigation (FBI) that Lanza felt pity for children, believing they were being improperly controlled by parents and teachers. She suspected Lanza may have viewed the killings as a way of saving or protecting them.
While Lanza had AspergerâÂÂs syndrome, obsessiveâÂÂcompulsive disorder (OCD), and severe anxiety, investigators emphasize these did not cause the violence. However, his mental health was completely untreated after 2008, leading to a "deteriorating life of dysfunction". By the time of the attack, he was severely anorexic, which medical experts believe caused cognitive impairment and may have contributed to a possible psychotic break or a "loss of touch with reality".
Shortly after the shooting, news stations received false reports that Ryan Lanza, Adam's older brother, was the perpetrator. Ryan found out about this while sitting at his desk at work. It was reported that his office in Times Square, New York was raided by police shortly after he found out about the false accusations. Ryan's Facebook was flooded with messages and comments shortly after news networks posted pictures of him. He made two posts on his Facebook account criticizing the media and harassers within three minutes of each other, likely before police raided his office.
The day following the shooting, Peter Lanza, Adam's father, released a statement:
In the immediate aftermath, states like Connecticut and New York passed some of the nation's most restrictive gun laws, including bans on certain semi-automatic firearms and high-capacity magazines. While initial federal efforts for universal background checks were blocked, the shooting eventually contributed to the passage of the Bipartisan Safer Communities Act in 2022âÂÂthe most significant federal gun legislation in nearly 30 years. Other federal laws inspired by the event include the STOP School Violence Act and the STANDUP Act, which provide funding for violence prevention education and suicide awareness in schools.
The families of the victims founded powerful advocacy groups that remain influential today, such as the Sandy Hook Promise, a national non-profit that trains students and teachers to recognize the warning signs of potential violence. Their programs have reached millions of children and are credited with preventing numerous school shootings and suicides. The shooting re-energized the broader gun violence prevention movement, leading to a decade of growth for organizations advocating for common-sense gun safety.
The shooting fundamentally altered how schools across the United States approach safety. Schools nationwide implemented locked-door policies, upgraded security cameras, and established secure entry points. Lockdown and active shooter drills became a standard part of the American K-12 educational experience for millions of students. Official reports, such as the one from the Connecticut Office of the Child Advocate, use Lanza's life as a case study for the dangers of extreme social isolation and untreated mental health crises. His story serves as a warning about the red flags that can occur when a person's profound developmental and emotional needs go unaddressed or are simply managed rather than treated.