Why were vigilante committees formed and how did they dispense justice?

In San Francisco, for example, the news of the discovery of gold to its north depleted its police force while simultaneously triggering an explosion in its population. The resulting increase in crime and violence prompted the establishment of a Vigilante Committee to maintain law and order. The Committee was made up of 600 local volunteers, most of whom were prominent members of the business community. During its first year (1851), the Committee hanged four lawbreakers, whipped one, deported 20 and released 41 after trial. As a result, violent crime was reduced in the city. The Committee was disbanded within a year after its creation. It was revived five years later and disbanded the same year.

The vigilante committee was created as a way of private citizens to administer law and order. The first ones that were created were in Philadelphia in 1840s and 1850s because of the Fugitive Slave Act as a way to help slaves that run away from the Southern States. They dispense justice because the root of their creation was when citizens believed that law and order were inadequate, such as the Fugitive Law.

#1 im pretty sure its a.

with my recent question