The Army was authorized to do this following the Colombian constitutional article that supported civilian arming as self-defense against a threat to their rights, and the Castaño brothers as well as other farmers in the region had armed themselves and hired bodyguards following this principle.
The military officially cut its links with these groups after finding out some of its members had ties to drug dealers.
By 1994, several of these farmers had grouped together forming a small army to fight the guerrillas as part of the ACCU, led by Fidel Castaño and still being financed by drug dealers.
The ACCU systematically eliminated left-wing sympathizers and peasant activists opposed to the farmers.
Within the newly created AUC, Castaño's ACCU continued to be the most powerful force for most of its existence.