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 school shootings in the US in the following eight years and found that in eight of those, "the shooters made explicit reference to Harris and Klebold." Larkin wrote "Numerous post-Columbine rampage shooters referred directly to Columbine as their inspiration; others attempted to supersede the Columbine shootings in body count." In 2012, sociologist Nathalie E. Paton of the National Center for Scientific Research in Paris analyzed the videos created by post-Columbine school shooting perpetrators. A recurring set of motifs was found, including explicit statements of admiration and identification with previous perpetrators. Paton said the videos serve the perpetrators by distinguishing themselves