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.

Research Summary: Public mass shootings tend to capture the public's attention and receive substantial coverage in both traditional media and online social networks (OSNs) and have become a salient topic in them. Motivated by this, the overarching objective of this paper is to advance our understanding of how the public responds to mass shooting events in such media outlets. Specifically, it aims to examine whether distinct information seeking patterns emerge over time and space, and whether associations between public mass shooting events emerge in online activities and discourse. Towards this objective, we study a sequence of five public mass shooting events that have occurred in the United States between October 2017 and May 2018 across three major dimensions: the public's online information seeking activities, the media coverage, and the discourse that emerges in a prominent OSN. To capture these dimensions, respectively, data was collected and analyzed from Google Trends, LexisNexis, Wikipedia