Social networks foster the development of social sensing to gather data about situations in the environment. Making sense of this information is, however, a challenge because the process is not linear and additional sensed information may be needed to better understand a situation. In this paper we explore how two complementary technologies, Moira and CISpaces, operate in unison to support collaboration among human-agent teams to iteratively gather and analyse information to improve situational awareness. The integrated system is developed for supporting intelligence analysis in a coalition environment. Moira is a conversational interface for information gathering, querying and evidence aggregation that supports cooperative data-driven analytics via Controlled Natural Language. CISpaces supports collaborative sensemaking among analysts via argumentation-based evidential reasoning to guide the identification of plausible hypotheses, including reasoning about provenance to explore credibility. In concert, these components enable teams of analysts to collaborate in constructing structured hypotheses with machine-based systems and external collaborators.