In high school, Lanza used to slither through the hallways, awkwardly pressing himself against the wall while wearing the same green shirt and khaki pants every day. He hardly ever talked to classmates and once gave a presentation entirely by computer, never uttering a single word.
"As long as I knew him, he never really spoke," said Daniel Frost, who took a computer class with Lanza and remembered his skill with electronics.
Lanza seemed to spend most of his time in his own large space in the basement of the home he shared with his mother - the same basement where she kept a collection of guns, said Russell Ford, a friend of Nancy Lanza's who had done chimney and pipe work on the house.
A week ago, Lanza fatally shot his mother before blasting his way into the school, killing 20 children and six teachers with a military style rifle. As police approached, he used a handgun to commit suicide.
Multiple funerals and visitations were held Friday as the community and the nation continued to mourn the lives lost at Sandy Hook. At the hour of the attack, 9:30 a.m., a bell tolled 26 times, once for each victim killed at the school.
Nancy Lanza was often seen around town and regularly chatted up friends and acquaintances at a local restaurant, but her 20-year-old son was a mysterious figure who was seldom spotted in this community of rolling hills and clapboard colonial homes, according to Ford and other townspeople.
The basement of the Lanza home was fully carpeted and had artwork, including a picture of a horse, on the walls. There was a computer, a flat-screen television, couches and an elaborate setup for video games. Nancy Lanza kept her guns in what appeared to be a secure case in another part of the basement, Ford said.
"She was from gun culture. Live free or die. That was truly her upbringing," said Ford, who often met the New Hampshire native and other friends at a regular Tuesday gathering at My Place, a local restaurant.
Ford did not know if Lanza brought her son shooting.
During the past year and a half, Ford said, Nancy Lanza had told him that she planned to move out West and enroll Adam in a "school or a center." The plan started unfolding after Adam turned 18.
"He wouldn't be dwelling with her," said Ford, who remembered that Adam Lanza never spoke to him or even made eye contact.
"She knew she needed to be near him," he added. "She was trying to do what was positive for him."
Ford said Nancy Lanza didn't elaborate on what type of services she wanted her son to receive. He hadn't seen her in about a month and a half, and said she made fewer appearances at the restaurant in recent months.
Mark Tambascio, owner of My Place, said Nancy Lanza described the same plan to him, saying she might move to Washington State.
Back in high school, Frost recalled, Lanza once made a class presentation about how to change the folders in Microsoft Windows different colors. He did it without saying a word, just demonstrating the steps on a screen.
Someone in the class brought in a video game called "Counter-Strike," a first-person shooting video game in which players compete against each other as either terrorists or counter-terrorists, Frost said.
Lanza "seemed pretty interested in the game," Frost recalled, and would play it with other students. He remembers the weapons Lanza chose: an M4 military-style assault rifle and a Glock handgun.
During the rampage at the school, Lanza used a military-style assault rifle and carried handguns, authorities said.
A week after the massacre, authorities still have no clear reason why Lanza would lash out at defenseless first-graders and their caretakers.
State police spokesman Lt. J. Paul Vance said it is too soon to draw any conclusions. A final report on the investigation could be months away.
Lanza destroyed the hard drive of his computer before the attack, and investigators have been unable to retrieve any information from it, according to a person briefed on the case.
And while they haven't given up, they aren't confident they will be able to repair it, the person said, speaking on condition of anonymity because he was not authorized to discuss the case publicly.
A moment of silence was held Friday in remembrance of those killed at the school. Gov. Dannel P. Malloy gathered with other officials in rain and wind on the steps of the Edmond Town Hall as the bell rang. Officials didn't make any formal remarks, and similar commemorations took place throughout the country.
Also on Friday, the National Rifle Association spoke out for the first time since the shootings, calling for armed police officers to be stationed at schools to stop the next killer "waiting in the wings."
Wayne LaPierre, CEO of the nation's largest gun-rights lobbing group, said at a Washington news conference that "the only thing that stops a bad guy with a gun is a good guy with a gun."
LaPierre blamed video games, music and videos for exposing children to violence.
The founder of a video game website said he expects tens of thousands of players of online shooter games to participate in a 24-hour cease-fire that started at noon Friday. Antwand Pearman, founder of GamerFitNation, said the cease-fire is meant to show respect for those killed in the Newtown shooting. He said, however, that video games don't cause violence.
At the memorial services, a school psychologist who rushed toward the gunman was remembered as a caring professional, a passionate fan of the Miami Dolphins and a woman who ultimately put the lives of others ahead of her own.
One of Mary Sherlach's friends donned a Dan Marino jersey for his eulogy at her funeral, which drew a standing-room-only crowd to St. Stephen Roman Catholic Church in Trumbull.
The church was adorned with a Christmas tree and several wreaths and bouquets, including one with the teal, white and orange colors of the Dolphins.
Rev. Stephen Gleason said Sherlach's love was Christ-like.
"No one has greater love than to give one's life for his friends," he said. "And she did so in an attempt to save others."
Five other victims from Sandy Hook had services or calling hours scheduled on Friday.
Associated Press writers Matt Apuzzo in Washington and Pat Eaton-Robb in Newtown contributed to this report.