Most research on encounters between persons with mental illness and the law enforcement system has focused on the extent to which persons with mental illness are shifted between the mental health and law enforcement systems. This article focuses instead on the interplay between the mental health and law enforcement systems for a group of persons with severe mental illness who continue to be actively treated by an Assertive Community Treatment (ACT) program. To better understand the connection between these two systems, profiles were constructed for 100 ACT clients, including data about arrests, other contacts with the law enforcement system, and mental health treatment. Results indicate that although the majority of ACT clients had some contact with the law enforcement system, most police encounters and arrests were for minor infractions. Those clients with the most frequent and serious contacts also received more expensive and intensive mental health treatment. Implications for future research and program design are discussed.