NEWTOWN, Conn. – As the nation paused for the one-week anniversary of the shootings at Sandy Hook Elementary School, new details emerged Friday about the gunman, Adam Lanza, who acquaintances said was able to take apart and reassemble a computer in a matter of minutes but rarely spoke to anyone.

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.