In high school, Lanza would walk 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 his classmates.
"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 could take apart and reassemble a computer in a matter of minutes
Lanza seemed to spend most of his time in the basement of the home he shared with his mother, who kept a collection of guns there, said Russell Ford, a friend of Nancy Lanza's who had done chimney and pipe work on the house.
Nancy Lanza was often seen around town and regularly met friends at a local restaurant. But her 20-year-old son was seldom spotted around town, Ford and other townspeople said.
The basement of the Lanza home had a computer, flat-screen TV, 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, said Ford, who often met her and other friends at a regular Tuesday gathering at My Place, a local restaurant.
Back in high school, Frost recalled, someone brought in a video game called "Counter-Strike,"
a shooting video game in which players compete against each other as either terrorists or counter-terrorists.
Lanza "seemed pretty interested in the game," Frost said, and would play it with other students. He remembers the weapons Lanza chose: an M4 military-style assault rifle and a Glock handgun.
Authorities said Lanza used a military-style assault rifle and carried handguns during the rampage at the school. They still have no clear reason why Lanza would lash out at defenceless first-graders and their caretakers.