This thesis paper intends to examine the impact of the 1999 Columbine massacre on succeeding mass shootings in the United States and how it became a source of inspiration and example for mass murderers. The issue of generalized imitation and contagion, induced by news coverage and improper handling of information about the perpetrators is introduced and analyzed. The historical significance of American gun culture, the problematics of perpetrator-focused media representation, sensationalism and the release of detailed facts about the assailants collectively caused the notoriety and strong influence of the shooting. All contributing factors are investigated in the paper, including parts of the news coverage of the incident, the private writings and home videos of the shooters, and attacks that were inspired by the gunmen. The connection of generalized imitation and the contagion effect, as phenomena connected to the topic, is explained and applied to the shooting.