Project Safe Neighborhoods, which is a national initiative coordinated through U.S. Attorneys' Offices, is a strategic, coordinated approach to reducing gun violence in the Nation. This working paper is part of the effort to design data-driven strategies that produce measurable decreases in firearms-related crime and to improve the long-term ability of Federal, State, and local agencies to cooperate in understanding, prosecuting, and preventing firearms-related violent crime. The analysis of homicide patterns across the five sites found that many homicides involved Hispanic and Black young adults, reflecting the racial composition of the communities; involved the use of handguns; occurred outdoors; and resulted from disputes between strangers. Given these data on the features of homicides in the five sites, this paper describes interventions likely to be effective in preventing and countering homicides. The types of interventions described involve directed patrol and field interrogations; the vigorous enforcement and prosecution of firearms laws; holding gangs collectively responsible for the activities of individual members; and the use of education, life-skills training, and substance abuse treatment to prevent violent behaviors. The study examined homicide case files for 4-year periods in the targeted sites. Information was coded on the time, location, motive, method of homicide, victim characteristics, and the characteristics of known offenders. 4 tables and 53 references