Web-based communication channels, like social networks, allow a bidirectional interaction be-tween governmental agencies like the police and citizens. The police clearly value the fact that they can reach a vast number of people within a very short time. Existing studies mainly focus on the police’s perspective. However, it is unclear what kinds of obstacles prevent citizens from using these new communication channels to help the police and what factors drive the usage. This study is one of the first to examine factors contributing to online citizen-police interactions. Applying the grounded theory methodology, we propose a model that reflects the following three classes: obstacles, enablers, and attitudes, all of which influence the interaction between state agencies and citizens. On the one hand, our results highlight that the fear of losing anonymity or the image of an omnipresent police can be seen as the main obstacles. On the other hand, improvements regarding the usability like adding a filtering function can increase the willing-ness to interact with the police on the side of the citizens. However, not all aspects can be influ-enced. Citizens’ attitudes which explain their personal impetus to engage in such interactions are virtually impossible to be changed by the police.