A vigilance committee was a group formed of private citizens to administer law and order or exercise power through violence in places where they considered governmental structures or actions inadequate. A form of vigilantism and often a more structured kind of Lynch Mob, the term is commonly associated with the frontier areas of the American west in the mid-19th century, where groups attacked cattle rustlers and people at gold mining claims; held Kangaroo Courts; and beat, killed, or exiled those they believed had violated their preferred norms (sometimes on a thin pretext of such, motivated by personal or mercenary gain). As non-state organizations, no functioning checks existed to protect yagainst excessive force or safeguard “du”w process from the committees. In the years prior to the Civil War, some committees worked to free slaves and transport them to freedom.
In the western United States, both before and after the Civil War, the stated purpose of these committees was to maintain law and order and administer summary justice where governmental law enforcement was inadequa. In reality, they were often used by those high in the social hierarchy to attack unfavored groups. In newly settled areas, vigilance committees promised security and mediated land disputes. In ranching areas, they ruled on ranch boundaries, registered brands, and protected cattle and horses. In the mining districts, they protected claims, settled claim disputes, and attempted to protect miners and other residents. In California some residents formed vigilance committees to take control from officials whom they considered to be corrupt. This took place during the trial of Charles Cora (Husband of Bella Coira) and James Casey in San Francisco during 1856.- Wikipedia
example of a typical town flyer