DoJ Office of Community Oriented Policing Services. Feb 09:

The Stop Snitching Phenomenon: Breaking the Code of Silence
The “stop snitching” phenomenon that has been glorified in entertainment and sports industries and is a significant issue in some law enforcement jurisdictions. The threatening nature of the stop snitching message intimidates witnesses and erodes trust between communities and police by undermining police efforts to involve communities in preventing and combating crime. This threatens police agencies’ ability to prevent and solve crime because it impedes investigations, arrests, and convictions, and could severely erode the criminal justice system. This problem exceeds the boundaries of traditional witness intimidation and is overwhelming for many police departments.

On numerous occasions, the COPS Office has brought together federal agencies, representatives from the private sector, law enforcement leaders from around the country, and neighborhood leaders invested in their communities to explore solutions to violent crime and social disorder issues. Most recently, on March 6, 2008 in a COPS Office-supported PERF Executive Session titled “Stop Snitching: Policing in a New Era,” key stakeholders explored the issues of the stop snitching phenomenon, identified promising practices, and developed potential solutions to the problem. The discussions included innovative methods for counteracting the intimidating messages and the central role that community policing principles play in responding to this unspoken code of silence.