Interactions between humans and machines are often placed in a multi-layered network involving the multidimensional trust in communication, information, and socio-cognitive layers. In this complex environment, how to filter and fuse heterogeneous data is critical for effective decision making. In this work, we propose an ontology-based framework for information fusion, as a support system for human decision makers. In particular, we build upon the concept of composite trust, consisting of four trust types: communication trust, information trust, social trust, and cognitive trust.