Narco-war
There are 6 separate wars being fought in Colombia at the moment. This is, I think you'd agree, far too many for such a small country. Marxist guerrillas FARC are fighting over slim territory with rival left wing insurgents the ELA. FARC and the ELA are both fighting the Colombian State, still unable to vanquish their fierce challenge. The State has recently acquired a new enemy in a right wing paramilitary group called the AUC, a one-time ally and auxiliary of the army. The whole reason for the existence of the AUC, meanwhile, is to wipe out FARC and the ELA, so they're all at war with each other as well.
FARC and the ELA are long-established and run a semi-operational social system inspired by Marx-Mao-Leninism, similar to Peru's Shining Path in the 70s and 80s. Outside locale, the ELA are relevant because they fight FARC. FARC, meanwhile, are the most famous of Colombia's terrorist factions. They get the most press and the most hassle. This has something to do with their success and their audacity. They are larger and better equipped than the ELA, and pull outrageous stunts that provoke exciting headlines. They make money from coca production and extortion but extract political capital from kidnapping senior politicians from cities and government buildings, or hijacking their planes. Generally, when people think of Colombia, they think of drug cartels. If they know anything more, they think of FARC.
The AUC, however, would lag in their memory. This is strange because, of the average toll of civilian deaths per year in Colombia (3500), FARC and the ELA are collectively responsible for 15% of them, while the AUC can claim 75%.
The AUC has its origin in semi-official counter-insurgency militias that were organised to fight the methods and effects of the guerrillas. The core of the AUC formed around two men, both prominent figures in Colombia's drug cartels: Jose Rodriguez Gacha and Fidel Castano. These two drug lords were typical of the type in that they used their vast and illicit wealth to become important landowners. Cartel members are known to have brought up to 3.5 million hectacres of Colombian farmland. This put them in direct conflict with FARC and the ELA, who both controlled drug production in their peasant enclaves, as well as dealing with local landowners by means of extortion, kidnap, and murder. In fact, Castano's father had been killed by FARC guerrillas, and the Castano clan had sworn revenge from that moment on.
These were the roots of the AUC, formally inaugurated in 1997, with the blessing (and money) of the army, the government, business leaders, landowners, drug barons, and the US. The AUC were, originally, considered a formal subdivision of the Colombian military machine, a de facto special force. Their money came from vast donations from the landowners and narco-traffickers they protected; from participation in the drug trade itself; and from the redirection of US aid from the Colombian military. Their aim was to completely eliminate the existence and influence of FARC and the ELA in their rural strongholds.
Loretta Napoleoni describes an incident which illustrates their methods:
On 25 October 1997, members of the AUC and the 4th Brigade of the Colombian army, attacked the village of El Aro, in an area reputed to be sympathetic to FARC, the left-wing guerrillas. The army encircled the village, preventing anyone from escaping, and the AUC proceeded to exterminate the population. A shopkeeper was tied to a tree and brutally tortured before being castrated: his eyes were gouged out and his tounge severed with a knife. Eleven people, among them three children, were beheaded; all the public buildings were set on fire, houses were looted and the water supply destroyed. The AUC and the 4th Brigade left with 30 people, who are now some of the thousands of missing Colombians. The butchery in El Aro had a specific aim: to terrorise FARC sympathisers in an area targeted by the AUC and the army.
The AUC is now "outlawed" (it was added to the US list of terrorist organisations which expanded exponentially after 9/11) and currently fighting the Colombian army, despite strong links that remain between the two. AUC squads continue to massacre peasants, trade unionists, left wing politicians, left wing anyone, humanitarian/aid workers, local leaders, and land reform activists. They boast 10,000 paramilitaries, a number growing rapidly. In a recent bid for good publicity they announced that, from now on, they would not execute more than 3 people during every attack. This is, apparently, "something, at least."