Diagnosis of anomalous routing states is essential for stable inter-AS (autonomous system) routing management, but it is difficult to perform such actions because inter-AS routing information changes spatially and temporally in different administrative domains. In particular, the route hijack problem, which is one of the major routing-management issues, remains difficult to analyze because of its diverse distribution dynamism. Although a multi-agent-based diagnostic system that can diagnose a set of routing anomalies by integrating the observed routing statuses among distributed agents has been successfully applied to real Internet service providers, the diagnostic accuracy depends on where those agents are located on the BGP topology map. This paper focuses on the AS adjacency topology of an actual network structure and analyzes hijacked-route behavior from the viewpoint of the connectivity of each AS. Simulation results using an actual Internet topology show the effectiveness of an agent-deployment strategy based on connectivity information.