Certain described examples are directed towards analyzing network data. The network data is processed to generate a graph data structure that has edges that are associated with communication times from the network data and nodes that are associated with computer devices. Representations of the graph data structure are generated over time. Given an indication of at least a computing device, for example as involved in anomalous activity or a security incident, the representations of the graph data structure may be used to determine further associated computer devices that are associated with the indicated device.