Columbine by Dave Cullen:
Personal affinities also obscured the problem. Mr. D knew he was drawn to sports. He worked hard to offset that by attending debate tournaments, drama tryouts, and art shows. He conferred regularly with the student senate. But those were all success stories. Mr. D balanced athletics and academics better than overachievers and unders.
“I don’t think he had a preference on purpose,” a pierced-out girl in a buzz cut and red tartan boots said. “He’s got a lot of school spirit, and I think he aims it in the direction he’s most comfortable with, like school sports and student congress.” She saw DeAngelis as a sincere man, making a tremendous effort to interact with students, unaware that his natural inclination toward happy, energetic students created a blind spot for the outsiders. “My Goth friends hated the school,” she said.