Stockholm policeman Martin Beck is called in to investigate the murder of a fellow officer. Beck and his partner, Einar Ronn, soon discover that the murdered policeman was well known to his colleagues for his excessive brutality, though his misdeeds were never reported to higher authorities. As they pursue their investigation, a sniper climbs to a roof in downtown Stockholm and starts firing at every uniformed officer he sees.

Instructional videos on how to survive an active shooter send a paranoid man into a self-fulfilling spiral.

A film featuring the response by several office workers in response to an Active Shooter attack.