Due to the rapid propagation of rumours in Online Social Networks (OSNs), identifying and understanding characteristic patterns, evolution and user behaviours behind this activity is essential. Yet, there are few tools that can support analysing rumours and activities of players in their propagation. In this paper we propose a visual analysis approach to explore rumour components and life cycles as well as their association with user actions. The approach is realized by the implementation of a prototype system, called RumourFlow. Our framework designs, adopts and implements multiple visualizations and modeling tools that are integrated to reveal rumour contents and participants' activity, both within a rumour and across different rumours. The approach supports analysts in drawing hypotheses regarding rumour propagation. This paper presents the various models, algorithms and visualizations employed for rumour strength, rumour contents, user participation, as well as the core role of the visualizations in studying this phenomenon. The effectiveness of the approach is illustrated by a use case highlighting relevant insight into rumour spreading, most of which could not otherwise be observed.