Columbine High School massacre Potential Students") program. He found the transition to Ken Caryl Middle School difficult. Unlike the white caps of the jocks, Harris and Klebold wore black baseball caps. As was typical in the 1990s, they wore them backwards. Harris wore a KMFDM cap, and apparently did not wear it during the massacre. Klebold's cap had a Colorado Avalanche logo on the front and a Boston Red Sox logo sewn onto the back. Following the Columbine shooting, schools across the United States instituted new security measures such as see-through backpacks, metal detectors, school uniforms, and security guards. Some schools implemented school door
Columbine High School massacre more than two-thirds of the attacks. A similar theory was expounded by Brooks Brown in his book on the massacre, "No Easy Answers"; he noted that teachers commonly ignored bullying, and that whenever Harris and Klebold were bullied by the jocks at CHS, they would make statements such as: "Don't worry, man. It happens all the time!" if anyone expressed shock or surprise. Dave Cullen disputes the theory of "revenge for bullying" as a motivation. While acknowledging the pervasiveness of bullying in high schools including CHS, he has claimed they were not victims of bullying. He said Harris was more