Prior research on the relationship between economic development and murder rates on the cross-national level has produced inconsistent results. This article argues that the relationship between economic development and murder rates can be better understood by adopting the notion of active social control, operationalized as political democracy and mass communication. It is proposed that high levels of active social control, resulting from economic development, will counterbalance the potential for violent behavior and thus reduce murder rates. The findings from an analysis of cross-sectional data from 39 nations support the hypothesis. It is argued that the notion of active social control can be integrated into Durkheim's theory of social solidarity and deviance to build a unified theory of murder and violent behavior.