This thesis describes the research and development of a prototype for a co-located collaborative intelligence analysis tool: ACH Walkthrough. The tool is a collaborative variation of an established structured analysis method called Analysis of Competing Hypotheses, originally developed for intelligence analysis. Recent changes to web application architectures offer important opportunities to produce visually rich applications that support co-located and remote collaborative decision making scenarios. We begin by reviewing the literature on sensemaking and development frameworks for surface applications. We explore architectural issues in using web frameworks for collaborative applications. We then present the design and implementation of ACH Walkthrough, our prototype design for team-based intelligence analysis, and the evaluation of the application's major architectural components. Finally, we document feedback on the tool and explore alternative designs and architectural approaches.