One of the first militias was formed in the community of Rio das Pedras and came to be known as the 'polícia mineira' (mining police). This group of residents, comprised mainly of northeastern migrants, became increasingly reckless in the years that followed.

In the early 1990s a similar model was adopted by the communities of Gardênia Azul and Tijuquinha, which are both located close to Rio das Pedras. From 2004, there was a large scale expansion of the militias to cover areas in Bangu, Penha, Engenho de Dentro, Pilares and Ramos, amongst others. These often involved lethal armed battles to remove existing criminal groups from control.

Research conducted by anthropologist Alba Zaluar suggests that militias have gained control of 454 favelas in Rio, accounting for 45% of the total favela population.  They have come to occupy large swathes of the West Zone of the city and other areas of the suburbs and the North Zone. However, they have not gained any significant territory in the South Zone to this day.