Citizen informer corps

Overview
A citizen informer corps is any group of citizens, formal or informal, recruited by the government for the purpose of informing the government of certain types of activities by their fellow citizens. The phrase "suspicious activities" is often used as a catch-all category which the government can then refine as needed for targeting specific groups or individuals.

Such a corps can also be used for other questionable tasks, as its members will lack either training or a tradition of service to inform them of their proper role or of which received orders might be inappropriate, unethical, or even illegal. Obvious uses include dissemination of propaganda, persuading others to go along with government orders (whether legal or not), or even the use of force.

Recent

 * Clergy response teams, according to the one source describing them, skip the "informer" role and go straight to the propaganda and persuasion, but it's not clear if they were more than a rumor.

Fictional

 * The Night Watch story arc in Babylon 5