(CBS News) SAN DIEGO - The clues to what provoked this senseless crime may lie in the suspect's past.
Twenty-four-year-old James Holmes left different impressions on people he encountered in life. At the University of California, Riverside, where he graduated with honors in neuroscience in 2010, he's remembered as brilliant.
"He was an honor student, so academically he was at the top of the top," University Chancellor Tim White said at a press conference. "He really distinguished himself from an academic point of view during his four years with us, graduating with highest honors."
But back in the northern suburbs of San Diego, where Holmes grew up, friends came and went from his house all day. His father, surrounded by police, left for Denver early Friday morning.
Julie Adams lived around the corner. Her son played soccer with James. She says his intelligence was obvious early on.
"People come here because of the school district," Adams said, "so there's lots and lots of kids because of that and obviously his parents wanted to give him the best and that's why they lived here."
In high school, Holmes won a competitive position at a rigorous science boot camp and an internship in neurobiology at the prestigious Salk Institute.
Tom Mai, who lived next door with his family for a decade, remembers James as smart, quiet, polite.
"He seemed to be very nice, young, typical American boy," Mai said.
But Anthony Mai, 16, said Holmes was shy to the point of being a loner.
"Like, as much as he was always smiling all the time that I was around, the fact that he was quiet, you know, something just looked kind of weird," Anothony said. "It was just a feeling in my gut that I had that something was going on, but I wasn't sure."
Anthony says James seemed frustrated after earning his undergraduate degree in neuroscience when the only job he could get was at McDonald's. This smart, shy, frustrated loner applied and was admitted to graduate school at the University of Colorado. He dropped out in June.