NEWTOWN, Conn. — She was “a big, big gun fan” who went target shooting with her children, according to friends. She enjoyed craft beers, jazz and landscaping. She was generous to strangers, but also high-strung, as if she were holding herself together.

Nancy Lanza was the first victim in a massacre carried out on Friday by her son Adam Lanza, 20, who shot her dead with a gun apparently drawn from her own collection, then drove her car to Sandy Hook Elementary School, where he killed 26 people, 20 of them small children, officials said.