Words symbolically represent communicative and behavioral intent, and can provide clues to a communicator's future actions in online communication. This paper describes a sociotechnical study conducted from 2008 through 2015 to identify deceptive communicative intent within group context as manifested in language‐action cues. Specifically, this study used an online team‐based game that simulates real‐world deceptive insider scenarios to examine several dimensions of group communication. First, we studied how language‐action cues differ between groups with and groups without a compromised actor. We also examine how these cues differ within groups in terms of the group members' individual and collective interactions with the compromised actor. Finally, we look at how the cues of compromised actors differ from those of noncompromised actors, and how communication behavior changes after an actor is presented with an ethical dilemma. The results of the study further our understanding of language‐action cues as indicators for unmasking a potential deceptive insider.