The study is based on interviews with 32 criminal justice professionals from 20 urban jurisdictions, including prosecutors; victim services directors; Federal, State, and local law enforcement officers; judges; and scholars. Also included are the insights of a working group of 20 criminal justice professionals who met in September 1994 to exchange information on emerging responses to the problem of victim and witness intimidation. Prosecutors in some jurisdictions report an increase in victim/witness intimidation; some estimate intimidation as a factor in 75 to 100 percent of the violent crimes committed in some gang-dominated neighborhoods. Each case-specific act of violence against victims or witnesses promotes the communitywide perception that any cooperation with the criminal justice system is dangerous. Factors that contribute to the reluctance of witnesses to cooperate with the criminal justice system include fear, strong community ties, or a deep-seated distrust of law enforcement. Factors that increase the likelihood of intimidation include the violent nature of the initial crime, a previous personal connection to the defendant, geographic proximity to the defendant, and membership in a culturally vulnerable group. Traditional approaches for combating victim/witness intimidation include warnings to the defendant concerning obstruction of justice laws, high bail, aggressive prosecution of reported intimidation attempts, and witnesses' entry into the Federal witness security program. Some innovative interventions are emergency relocation and support for witnesses; innovative courtroom security measures; interagency cooperation to relocate witnesses who live in public housing; secure segregation of intimidated victims/witnesses in correctional facilities; and community outreach and collaboration among criminal justice, social service, and community groups. This report also provides guidelines for establishing a comprehensive witness security and assistance program. 15 notes