In April 2013, two bombs exploded near the finish line of the 117th annual Boston Marathon. Following the incident, the media portrayed a devastating attack, while simultaneously exemplifying the city of Boston as triumphant and unified. In the current study, we examined not only how in-lab framings of terrorist activity influenced threat perception, but also how the effects of the in-lab framings changed over time, as actual media coverage of the event fluctuated around its anniversary. To test this, participants repeated the same experiment three times surrounding the anniversary as news coverage of the incident predictably rose and fell. Participants were randomly assigned to watch one of three videos: a negative bombing video that contained photos of the bombings accompanied by negative news headlines and affectively negative music, a positive bombing video that contained the same photos but accompanied by positive news headlines and affectively positive music, or a control video that did not contain images of the bombings. Following the video, a Shooter Bias Task was completed in which participants decided whether to “shoot” or “not shoot” a series of armed and unarmed individuals. Results revealed that participants in the negative bombing condition had a significantly greater tendency to favor the “shoot” response compared to participants in the positive bombing condition, but only at the waves of data collection furthest from the anniversary. These findings have important implications for how the media frames incidents of mass violence. Future research could explore individual differences that drive susceptibility to framing effects.