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Autodefensas Unidas de Colombia – AUC

Autodefensas Unidas de Colombia – AUC

The United Self-Defense Forces of Colombia (Autodefensas Unidas de Colombia – AUC) was a coalition of far-right paramilitary armies. According to their main leaders, their objective was to stop the expansion of leftist guerrillas in Colombia. However, they camouflaged a broad portfolio of criminal economies and war crimes including drug trafficking, forced displacement and disappearances, land grabbing, kidnapping, and extortion, among others under the guise of counterinsurgency operations.


The origins of paramilitary groups in Colombia date back to the late 1970s, when small self-defense groups emerged in the Magdalena Medio region with the aim of confronting the guerrillas and collaborating with the army in counterinsurgency work. However, it was not until a series of meetings held in 1982 between cattle ranchers, businessmen, politicians, and the military in the municipality of Puerto Boyacá, that the foundations for what would become the AUC were laid: private armies with close ties to key local, regional, and even national elites.

Following a wave of kidnappings by guerrilla groups, Colombia’s notorious drug traffickers —among them Pablo Escobar, Gonzalo Rodríguez Gacha, and the Ochoa brothers— decided to create a death squad they called Death to Kidnappers (Muerte a Secuestradores – MAS).

This illegal group was not only dedicated to killing kidnappers but anyone they suspected of belonging to the guerrillas, including many innocent civilians, activists, union leaders, and politicians. From there, many of the self-defense groups ended up protecting drug trafficking interests under the façade of counterinsurgency.

The second generation of paramilitaries was born out of the Persecuted by Pablo Escobar (Perseguidos por Pablo Escobar – PEPES). The PEPES were a group of former associates of Pablo Escobar within the Medellín Cartel, who rallied against the criminal leader after he assassinated two of his closest collaborators. They were led by brothers Fidel, Carlos, and Vicente Castaño, who allied with Diego Fernando Murillo Bejarano, alias “Don Berna”, to take Escobar down. This involved close collaboration with members of the security forces.

After Escobar’s assassination and the death of Fidel Castaño, the remnants of this group formed the Peasant Self-Defense Forces of Córdoba and Urabá (Autodefensas Campesinas de Córdoba y Urabá – ACCU), under the leadership of Carlos and Vicente Castaño. The ACCU began the paramilitary expansion throughout northern Colombia. They relied on the legally constituted figure of private security and surveillance cooperatives, known as Convivir. The Convivir were created by the Colombian government in 1994 as a strategy to promote cooperation between their associates and security forces regarding security and public order. However, emerging paramilitary groups —such as the ACCU— established these cooperatives in different parts of the country to gain access to weapons, and resources, and to strengthen their political and military networks.

In 1997, the Castaño brothers created a federation of different self-defense groups in the country, comprised of seven regional organizations. This umbrella organization became known as the United Self-Defense Forces of Colombia (Autodefensas Unidas de Colombia – AUC). These groups established themselves in the main areas of influence of the guerrillas, deeply impacting the civilian population. At its peak, the AUC had as many as 30,000 fighters in its ranks.

Soon after its foundation, drug traffickers began to link up with the paramilitary project, mainly through the purchase of AUC blocks in key places in the drug trafficking chain. With the incorporation of drug trafficking, the counterinsurgency objective of the AUC became increasingly blurred and generated internal struggles among the main leaders of the organization.

In late 2002, amid internal tensions, the AUC started negotiations with the Colombian government that led to an agreement for the demobilization of the paramilitary blocs in July 2003. In December of that year, the first demobilization of the AUC took place. More than 800 combatants of the Cacique Nutibara Bloc —with a presence in different communes of Medellín and some municipalities of Antioquia— disarmed in the city of Medellín.

During the demobilization process, disputes within the organization continued, resulting in the assassination of some of its main leaders, among them Carlos Castaño in April 2004.

In addition, the shortcomings of the demobilization process became evident. The government lacked the necessary infrastructure to verify the demobilization and handover of weapons from paramilitary groups. Some paramilitary groups deliberately deceived the government, turning in old weapons and passing off civilians as soldiers.

Moreover, some demobilized ex-paramilitaries returned to criminality, among them Vicente Castaño, who together with other AUC mid-level commanders created a criminal group in the Urabá region of northern Colombia. This group is one of the country’s main criminal groups now, known as the Gulf Clan or Gaitanist Self-Defense Forces of Colombia (Autodefensas Gaitanistas de Colombia – AGC).

Like the Urabeños, other groups emerged from paramilitary demobilization, including the Rastrojos, the Popular Revolutionary Anti-Communist Army of Colombia (Ejército Revolucionario Popular Anticomunista de Colombia – ERPAC), the Paisas, the Machos, Águilas Negras, and Renacer, among others.

In 2008, some of the main paramilitary leaders —including Salvatore Mancuso and Don Berna– were extradited to the United States to face drug trafficking charges. While some of them have returned to Colombia after serving their sentences, others are still in prison in the U.S.


The brothers Carlos and Vicente Castaño led the AUC from its origins in the late 1990s, with Carlos Castaño acting as the main commander. However, following disputes within the organization, Carlos Castaño resigned as the top commander in mid-2001, and other figures in the paramilitary leadership, such as his brother Vicente and Salvatore Mancuso Gómez, gained prominence.  

In addition to the main political and military commanders of the organization, each of the AUC blocs had its own leadership. Some of these commanders could act semi-independently of the organization’s top leadership, which hindered the group’s internal cohesion and the real influence of the general command on decisions in the regions where the groups were present.


At the height of its power, the AUC operated in two-thirds of Colombia, with a particularly strong presence in the Caribbean coast region in northern Colombia. However, the paramilitary blocs also expanded into other key regions of the drug trafficking chain, such as the Pacific coast, different departments of the Amazon region, and the eastern plains.

Allies and Enemies

The AUC’s main enemies were the country’s most representative leftist guerrillas: the Revolutionary Armed Forces of Colombia (Fuerzas Armadas Revolucionarias de Colombia – FARC) and the National Liberation Army (Ejército de Liberación Nacional – ELN).

To weaken their main adversaries and advance their interests, the AUC established important alliances with the military, businessmen, and politicians at the local, regional, and national levels. After the paramilitary demobilization, more than 250 politicians, including 72 congressmen and 15 governors, were convicted for links to paramilitary groups in a case known as “parapolítica” (para-politics). These alliances were key to the expansion of the paramilitary movement throughout large parts of the country.


Several of the main paramilitary commanders who were extradited to the United States in 2008 have returned to Colombia, where they face ongoing judicial proceedings for forced displacement and disappearances, massacres, homicides, and sexual abuses, among other crimes.

Upon their return to Colombia, some paramilitary commanders, such as Hernán Giraldo Serna, have lost the transitional legal benefits granted by the Justice and Peace Law (Justicia y Paz) for committing crimes after their disarmament. Others have sought to be included in the Special Jurisdiction for Peace (Jurisdicción Especial para la Paz – JEP), the justice mechanism created in the framework of the peace process between the Colombian government and the FARC guerrillas. They argue that besides being members of paramilitary groups, they were third-party financiers or collaborators. The first paramilitary chief to be admitted to this jurisdiction was Salvatore Mancuso, who returned to Colombia at the end of February 2024 after spending 16 years in prison in the United States.

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