The study found that the large gap in clearances (43 percent for gun murders compared to 19 percent for nonfatal gun assaults) was due primarily to sustained investigative effort in homicide cases after the first 2 days. Police departments should invest additional resources in the investigation of nonfatal gun assaults. When additional investigative effort is expended, law enforcement improves its effectiveness in gaining the cooperation of key witnesses and increases the amount of forensic evidence collected and analyzed. In turn, the capacity of the police to hold violent gun offenders accountable, deliver justice to victims, and prevent future gun attacks is enhanced. (publisher abstract modified)