Case law analysis is a significant component of research on almost any legal issue and understanding which agents are involved and mentioned in a decision is integral part of the analysis. In this paper we present a first experiment in detecting mentions of different agents in court decisions automatically. We defined a light-weight and easily extensible hierarchy of agents that play important roles in the decisions. We used the types from the hierarchy to annotate a corpus of US court decisions. The resulting data set enabled us to test the hypothesis that the mentions of agents in the decisions could be detected automatically. Conditional random fields models trained on the data set were shown to be very promising in this respect. To support research in automatic case-law analysis we release the agent mentions data set with this paper.