Data on the specific circumstances of deaths in the riots were taken from sources that used police reports, eyewitness accounts, and information from news media to reconstruct each riot. The circumstances and dates of 91 deaths were analyzed: 28 in the Watts riot, 21 in the Newark riot, and 42 in the Detroit riot. The findings demonstrated that police officers intiated 78.6 percent of the deaths in Watts, 80 percent in Newark, and 69 percent in Detroit. The analysis of dates of deaths revealed the violence initiated by civilians occurred during the early stages of each riot and that violence by the police and national guard came later. Officials became increasingly indiscriminate, random, and personal in their killing as the riots progressed. This trend is interpreted as evidence of rioting by white law enforcement officials. The causes for these police riots are linked to those for the civilians' riots. Both groups were motivated by forces of social change into outbursts of collective violence. During the early 1960's, the expansion of the Federal Government into local affairs generated reaction in both blacks and whites, who were alternately mobilized and dispossessed by the growing Federal power. Comparisons are made with the expansion of state power during the early phases of nation building in Europe and the collective violence that was generated. Related literature is reviewed. Tables, figures, graphs, footnotes, and approximately 60 references are included.