This study provides a partial test of Klinger's ecological theory of police behavior using hierarchical linear modeling on 1,677 suspects who had encounters with police within 24 beats. The current study used data from four sources originally collected by the Project on Policing Neighborhoods (POPN), including systematic social observation, in-person interviews with officers, census data, and police crime records. It investigates the effects of neighborhood violent crime rates and concentrated disadvantage on officer vigor, controlling for individual-level officer characteristics and situational factors. The analyses reveal that police vigor was significantly shaped by beat-level crime rates, with high--crime rate neighborhoods experiencing higher levels of police vigor in handling suspects. The findings are not consistent with the ecological propositions set forth by Klinger. Implications of these findings and suggestions for future research and theoretical development are discussed. (Contains 3 tables, and 12 notes.)