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 put us through this last year." Klebold shouted "All jocks stand up!" When nobody stood up, Harris said to "get the guys in white hats." One of them said "Anybody with a white hat on is dead". Wearing a white baseball cap at Columbine was a tradition among sports team members. Several students tried to hide their white hats. Noticing police evacuating students outside the school, Klebold said "Pigs are here" and Harris said: "Let's go kill some cops." They shot out the windows in the direction of the police. Officers returned fire, and the gunmen retreated from the windows;