Techniques and mechanisms are disclosed that enable network security analysts and other users to efficiently conduct network security investigations and to produce useful representations of investigation results. As used herein, a network security investigation generally refers to an analysis by an analyst (or team of analysts) of one or more detected network events that may pose internal and/or external threats to a computer network under management. A network security application provides various interfaces that enable users to create investigation timelines, where the investigation timelines display a collection of events related to a particular network security investigation. A network security application further provides functionality to monitor and log user interactions with the network security application, where particular logged user interactions may also be added to one or more investigation timelines.