Ex-pals told how the pasty-faced and scrawny 20-year-old was a deeply disturbed outcast beneath his image as a briefcase-toting computer nerd.
He is remembered as a goth who was sinisterly immune to pain.
Lanza gunned down 27 victims — including eight boys and 12 girls all aged six and seven — before shooting himself dead at Sandy Hook Elementary School in leafy Newtown, Connecticut, US, on Friday morning.
As it emerged that six-year-old British pupil Dylan Hockley was one of the victims, a neighbour and former classmate of Lanza summed up friends’ reaction to the horror.
Tim Dalton said: “Adam Lanza has been a weird kid since we were five years old. As horrible as this was, I can’t say I am surprised. Burn in hell, Adam.”
Lanza — thought to be a former pupil at Sandy Hook — drove up to the school in black battle fatigues and military-style vest.
He had two pistols — a Glock and a Sig Sauer — and a .223 semi-automatic Bushmaster rifle.
Lanza, who is believed to have rowed with teachers the previous day, blasted out a window at the front entrance.
He stormed into a corridor where he shot dead the headteacher and a school psychologist.
He then entered a classroom where most of the child victims died. All were shot more than once.
Four more female staff members died before jobless Lanza turned one of the guns on himself.
Lanza, who had Asperger’s syndrome and a personality disorder, had already blasted to death his mother Nancy, 52, at their nearby four-bedroom home — using guns she taught him to shoot with.
Pictures of mop-haired Lanza as a member of the Newtown High School Tech Club in 2008 emerged last night. The club ran nerdy “LAN” — local area network — parties at each other’s homes.
Beth Israel, whose son Alex knew Lanza, said: “He was very smart but I know he had issues. He was a really troubled kid. He was very quiet, a shy kid, socially awkward.”
A family friend said: “This was certainly a disturbed kid. He had major issues. He was subject to outbursts.”
Schoolmates dubbed Lanza a “brainiac” who stuffed pens in his shirt pocket and carried a black briefcase into English classes while other youngsters favoured backpacks.
If he was asked to speak in front of the class he was nervous and fidgety, “spitting his words out, as if having to speak up were painful”.
But ex-student Joshua Milas said: “He was probably one of the smartest kids I know. He was probably a genius.”
Former classmate Olivia DeVivo said: “If you looked at him you could not see any emotions going through his head.”
She recalled Lanza talking about “aliens and blowing things up”.
Former tech club member Tim Arnone said: “Lanza’s mom pushed him really hard to be smarter and work harder in school.”
One family friend claimed self-styled goth Lanza had a condition that left him oblivious to pain.
The pal said: “When he was on the baseball team a few years ago everyone had to be careful that he didn’t fall because he could get hurt and not feel it. Adam had a lot of mental problems.”
Ex-student Matt Baier said classmates did not pick on Lanza because of his Asperger’s.
He said: “From what I saw, people just let him be and that was that.”
One mother, Catherine Urso, said her son recalled Lanza as “very thin, very remote and one of the goths”.
Loner Lanza did not even appear in the Class of 2010 photo in his high school yearbook. His space said: “Camera shy.”
Police spokesman Lieut Paul Vance said last night that detectives had “very good” evidence about Lanza’s motive for the rampage.
But the officer dodged questions about whether the killer — who had never been in trouble with the law — left notes or clues on his computer about what sparked the horror.
There were claims that Lanza had an “altercation” with four school staff members the day before the slaughter.
Three were among his victims and the fourth, who was not at school, is being quizzed by investigators.
Retired local Lincoln Sandler said: “Everyone around here is saying Lanza had a deep resentment against the school, one that had been brewing for some time.”
Stunned locals yesterday laid flowers outside Sandy Hook school.
Sources revealed that Lanza’s mother Nancy — who had no connection to the school — owned the three guns he used.
They were found next to the killer’s body in one of the classrooms. Investigators are also said to have recovered a .45 Henry repeating rifle, a .22 Marlin rifle and a .30 Enfield rifle, although it is unclear where they were found.
Nancy’s gardener Dan Holmes told how she taught her son to fire the guns he shot her with.
He said: “They went target shooting as a family. That was a passion. The whole family would go together.”
Holmes said Nancy once showed her a “big, beautiful rifle” and added: “She was very proud of it. She loved her guns.”
A chilling internet “warning” posted two days before the massacre was being investigated by detectives last night.
The anonymous message was left on popular US forum site 4Chan, saying: “I’m going to kill myself on Friday and it will make the news, be watching at 9am.”
One user taunted the poster, claiming he “would not deliver”. Another asked: “Where at?”
The poster replied: “I live in Connecticut, that’s as much as I’ll say.”
Lanza launched his massacre minutes after the predicted time.
The message, left at 22.18 on Wednesday, is not the first time 4Chan has been caught up in scandal.
The site, launched in 2003, claims to have tens of millions of users. But it has also been accused of being a haven for “trolls” who launch vile attacks on others.
Viral campaigns launched through 4Chan have included flooding YouTube with porn or hacking corporate firms.
Lanza’s brother Ryan was watching news of the massacre on TV in his New York office when he was stunned to hear himself named as the suspect.
It is thought Lanza was carrying ID belonging to him.
Friend Brett Wilshe said he sent Ryan a Facebook message on Friday asking what was going on and if he was all right.
Ryan replied before cops took him in for questioning: “It was my brother. I think my mother is dead. Oh my God.”
Detectives will try to find out if the divorce of Lanza’s parents in 2009 had affected his state of mind.
His father Peter, £250,000-a-year vice president of GE Energy Financial Services, first heard of the massacre from a local newspaper reporter.
He stopped on the drive of his plush home, wound down the window of his blue Mini Cooper and asked: “Is there something I can do for you?”
After the newsman told him about the shooting, Peter’s surprised expression turned to shock and he drove into his garage in horrified silence.
Rhonda Cullens, a neighbour of Nancy, said: “She was a very nice lady, just a regular person.”
Friends of Lanza’s maternal grandmother Dorothy Hanson, 78, said she was “beside herself”.
Dorothy, who spends winter in a mobile home in Brooksville, Florida, said last night: “I’m just trying to absorb it.”
The killer’s cousin Andrew Lanza, 19, of Chicago, said he was “in shock and devastated”.
He said: “It’s hard for us because Adam’s part of our bloodline, no matter what.
“To hear that someone in your own family took the lives of children — it’s heartbreaking.”
- ‘He was not a troublemaker’|Those who knew Adam Lanza struggle to explain why he killed (rep-am.com)
- Gunman identified as Adam Lanza, 20 (wwlp.com)
- Why Did Adam Lanza Go On Shooting Rampage – The Story Behind the Man Who Killed 20 Children (americanlivewire.com)
- Adam Lanza Kills Mother Nancy Lanza Then Begins Murderous Rampage At Sandy Hook Elementary (americanlivewire.com)