The article first discusses the main characteristics, aspects, and issues of negotiations between the police and a terrorist. It then introduces the theoretical and technical notions required to represent the police/terrorist negotiations within the proposed formalism. The use of NEGOPLAN to support a police negotiator concludes the discussion. In its present version, NEGOPLAN only partially takes into account the strategic interactions between parties while giving the parties the ability to change problem representation according to their requirements. NEGOPLAN's architecture and the implemented problem representation increases the system's flexibility and broadens its support of negotiating parties. The article suggests how NEGOPLAN can be used in the development of negotiators' skills, but it is not recommended for use during an actual hostage-taking incident. 3 figures, 34 references.