The, Police Executive Research Forum is completing a major initiative that encourages police chiefs to formalize working relationships with emergency medical personnel. The effort is sponsored by the U.S. Department of Justice, Bureau of Justice Assistance as a demonstration with the goal of preventing recurring violence that eventually leads to homicide. The initiative originally involved a consortium of emergency room clinicians, emergency medical service (EMS) personnel, as well as police executives. The collaboration initially focused on arguably preventable dimensions of domestic violence and homicide. However, after “9/11” and the ensuing anthrax crisis, the project developed into a three-step draft interactive protocol for earlier police intervention in situations involving possible deaths and mass casualties. With this shift in the project, Police Executive Research Forum’s (PERF) principal collaborators shifted from emergency clinicians to public health practitioners.