School shootings have been on the rise and researchers have documented a “contagion effect” in which school shootings increase in probability during a 2-week period following an event (e.g., Towers et al. 2015). While there is a growing body of research examining media coverage of school shootings, more research is needed to investigate the role of media coverage during the specific 2-week contagion period. The purpose of the present research was to analyze the temporal changes of themes that emerge in social media throughout the contagion period and to assess relationships between themes that may ultimately facilitate the contagion effect. We conducted an analysis of Twitter posts following the Santa Fe High School shooting in Texas, which was preceded by two school shootings the week prior and followed by another school shooting a week later. The results supported previous research suggesting that sadness is associated with greater “psychological closeness” to the event. The results also showed that both sadness and anger were strongly correlated with information about the shooter, including the shooter's name. Discourse demonstrating awareness of school shooting contagion was associated with comments about the role of media in school shootings. These findings represent the first attempt to analyze social media during the specific 2-week contagion period. Implications regarding the extent to which these themes trigger the goals of a prospective shooter are discussed.