EXCLUSIVE: Santana School Shooter

Oct. 10 -- When 15-year-old Charles "Andy" Williams walked into a bathroom at his San Diego-area high school and started shooting, he didn't have a plan, he says.

Williams, who is now serving 50 years to life in a California prison, says he was "trying to prove a point" to kids who had been bullying him, but did not have a list of intended targets.

He admits that some of the people he shot were people he actually liked. "By that time, you know, my finger's on the trigger and I didn't recognize them until it was too late," he told Primetime's Diane Sawyer in his first television interview since the March 2001 killings.

Williams killed two fellow students during his six-minute rampage at Santana High School in Santee, Calif., and wounded 11 others, as well as a teacher and a campus monitor. He pleaded guilty to two counts of first-degree murder and 13 counts of attempted murder. One of the students who died, 14-year-old Brian Zuckor, was a classmate Williams remembers from English class as "a nice guy."

Missing His Mother

Williams had spent less than a year at Santana, joining the school as a freshman after he and his father moved to the area from a small town in Maryland. His parents had divorced when he was just 3, splitting the family, with Williams staying with with his father and his older brother moving to another state with their mother.

With 2,000 students, Santana High was bigger than the whole town Williams had lived in in Maryland, and he says he felt nervous about starting at a huge school. At previous schools Williams had played Linus in a school musical — complete with security blanket — had won an athletic award for "most spirit," and had earned the nickname "Mouse" from his peers. His best friend was a student with a form of muscular dystrophy.

But at Santana he fell in with a group of tough kids who smoked marijuana and, he says, bullied him. He says they called him names like "bitch" and "faggot," and singled him out because he was small and did not do anything to stop the bullying. Williams says he was smoking marijuana practically every day — "It was the only thing that, like, kind of sort of made me happy," he said, adding that he believes the drug had nothing to do with his rampage.