The research held constant the probability of interracial contacts and the total murder rate. The data came from supplemental homicide reports filed by the police to the Federal Bureau of Investigation during 1980-86 and from census data for 1970 and 1980. Cities with a black mayor and greater economic competition between the races had more killings of black persons by white persons than did other cities. The same hypotheses explained killings of white persons by black persons, but these killings were less likely in cities with black majors. In addition, police agency size did not explain killings of black persons by white persons, but cities with larger police departments had fewer killings of white persons by black persons. Findings suggested that economic rivalries and contests for political influence lead to greater interracial violence. Tables, footnotes, and 69 references