This paper takes stock on long-term research activities targeting the development of support systems for the intelligence analysts and the decision makers involved in situation analysis and sensemaking. It first reviews two notional models of situation analysis and sensemaking, which provides insights into these multifaceted processes. It then discusses the natural fit of knowledge-based systems technologies with intelligence analysis, and describes some previous work in knowledge representation, automated reasoning, and multiple hypothesis situation analysis. The current research efforts towards the integration of automated reasoning components within the multiple hypothesis framework are described. Finally, work in progress for the development of a multiple hypothesis sensemaking support system on a service-oriented architecture platform is presented.