Findings show very high levels of gun crime in St. Louis, with concentrations in particular neighborhoods. Gun crime typically involved high-rate offenders at risk for both victimization and perpetration of violence. A substantial number of these offenders and homicide victims were under probation and parole supervision. Most gun seizures occurred through traffic and pedestrian stops. The task force also recognized that there were significant gaps in processing gun crime cases and a lack of coordination between local and Federal prosecutors in deciding whether gun crime cases should be prosecuted federally or locally. This study selected 14 neighborhoods, chosen due to their high level of gun crime, for a comprehensive set of strategies. Included were targeted enforcement in the focus neighborhoods by law enforcement and probation, Federal-local gun case prosecution review, a most violent offender program, and probation notification meetings for high-risk probationers. Interviews indicate that PSN changed the business of addressing gun crime in St. Louis, significantly increasing information sharing among local, State, and Federal law enforcement agencies and consensus among PSN task force members of a shared priority and accountability for gun crime. Federal prosecutions for gun crime increased significantly, and gun crime offenders convicted in both State and Federal court received significant sentences. Interviews conducted with arrestees provided evidence that increased Federal prosecution had an impact on perceptions of the likelihood of prosecution and incarceration, at least for adult offenders. Violent gun crime declined significantly in St. Louis and targeted neighborhoods following PSN, but it is not clear if PSN generated the decline. Additionally, although gun crime declined in these target areas, the decline in arrests was not substantially different than that observed in the control and contiguous neighborhoods. Figures and references