Vigilance committee

A vigilance committee was a group formed of private citizens to administer law and order where they considered governmental structures to be inadequate. A form of vigilantism, the term is commonly associated with the frontier areas of the American West in the mid-19th century, where groups attacked cattle rustlers and gangs, and people at gold mining claims. As non-state organizations no functioning checks existed to protect against excessive force or safeguard "due 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 West.
In the western United States, both before and after the Civil War, the primary purpose of these committees was to maintain law and order and administer summary justice where governmental law enforcement was inadequate. In the newly settled areas, vigilance committees provided 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 Belle Cora) and James Casey in San Francisco during 1856.
Disbandment.
Vigilance committees were generally abandoned when the conditions favoring their creation ceased. In the west, as governmental enforcement increased and courts could dispense justice, residents abandoned the committees.
Nature.
Vigilance committees, by their nature, lacked an outside set of checks and balances, leaving them open for excesses and abuse.
In the West, the speed of the vigilance committees and lack of safeguards sometimes led to the innocent being hanged or to their just disappearing. A few committees were taken over by fraudulent individuals seeking profit or political office.