This study uses multivariate econometric and time series analysis techniques to examine historical trends in the felonious killing of law enforcement officers in the United States from 1947 to 1998. Of particular interest is the extent to which the correlates of police murder rates are characterized by historical specificity. We also focus on the ability of economic deprivation, deterrence, and social disorganization theories to explain trends in police murder rates across time. The findings of this study indicate (a) that police murder rates in the United States are characterized by distinct historical periods (1947 to 1971, 1972 to 1998) in which the structural correlates of police murder vary and (b) that both economic deprivation and deterrence theories are relevant for understanding trends in police murder although the effects of the latter are historically specific.