The database covers 2,226 homicides involving 2,415 victims and 2,650 offenders. Twenty-eight percent of the victims and 35 percent of the offenders were under age 25. Results revealed that young murderers generally kill people of the same age and racial group as themselves. In addition, patterns of homicide among people under age 25 differ substantially from those involving people over age 25. Young people who kill are more likely than older people to kill strangers and less likely to use guns. whereas homicides by older people are likely to be the result of a relationship problem, homicides by young people are primarily the result of altercations or occur in the course of other crimes. Findings suggest that central to homicide prevention is to focus on the most dangerous situations and on people who are at highest risk of victimization. Situational measures might include increased police presence in places known to attract large numbers of young people and the use of environmental design. In addition, innovative strategies to manage and control people's use of alcohol should be an integral part of any program aimed at preventing violence. Early identification and treatment of people with potentially high risks of offending is also crucial to preventing violent crime. Figures, tables, and 5 references