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 the staircase where the massacre began was in fact their preferred spot to wait for the bombs to go off. On Tuesday morning, April 20, 1999, Harris and Klebold placed two duffel bags each containing propane bombs in the cafeteria, set to explode at approximately 11:17 a.m, during the "A" lunch shift. Propane bombs were also placed in the cafeteria's kitchen. No witness recalled seeing the duffel bags being added to the 400 or so backpacks already in the cafeteria. The security staff at Columbine did not observe the bags being placed in the cafeteria, ostensibly because a custodian was