The BACRIM's control over territories such as the north Colombian region of Bajo Cauca comes at the point of a gun, and death is a constant price of their power.
In rural sectors, uniformed BACRIM armed with assault rifles still patrol in units that are a throwback to their paramilitary origins. But in the urban centers, their capacity for violence lies with their more hidden networks of "sicarios," or hitmen.
The sicario is one of the more specialized roles amongst the ranks of the BACRIM. Their only job is to kill or to torture when called upon. In Bajo Cauca, they are paid a wage of between 1.5 million and 3 million pesos (approximately $500 - $1,000) each month depending on how highly their skills are valued, and earn a bonus for each successful hit, which is usually 200,000 to 300,000 pesos (approximately $70 - $105). In special cases, these payouts can rise well into the millions.
Freelance sicarios -- those who are not on the Urabeños' books -- usually earn much more than their salaried counterparts, though it depends on the target. There are several high profile freelancers operating across Bajo Cauca, who BACRIM commanders usually bring in when their own ranks cannot be trusted, do not have the skills or do not posess the resources.
Most sicarios are recruited as teenagers. Local members of the BACRIM network will identify troubled or vulnerable children, often those with money or familial problems, and approach them with an offer of easy cash.
Fifteen-year-old "Juan," who did not want to use his real name, says he was offered 100,000 pesos (approximately $35) to kill someone when he was 13.
"They knew I was desperate and looking for work. I said no at first, but they followed me for a few days and eventually I agreed," he explained.
The murder was Juan's initiation into the BACRIM. He now lives with eight other young recruits in a house provided by the Urabeños. The small dilapidated shack has only two rooms and a piece of corrugated iron replaces the front door.
"I don't know who I killed or why, but I don't care," said Juan. "It's easier if you don't know anything about the target."
Such cold indifference is not unusual. The sicario is very rarely told who they are going to kill or why.
"Tomy," who also preferred to provide a false name, is 18 and also lives in the house. He is a "campanero" or lookout.
"I was homeless. They said they could give me somewhere to live," he said. "They gave me a phone and told me to keep an eye on everyone."
A home in the Caucasia slum known as "the Camel"
Campaneros, also known as "puntos," patrol their zone, looking for unfamiliar faces or strange activity and reporting anything unusual to their commander on a phone provided by the unit leaders. The campaneros also play a key role in gathering intelligence for assassinations.
Those who start further down the chain as campaneros or "extorsionistas" -- extortionists -- know they are usually on a career path to murder. Eventually, the day comes when the commanders decide to test their mettle, often by simply pressing a gun into their hands and giving them a target to kill. Training, if offered at all, usually involves an afternoon of basic weapons handling and target practice with a BACRIM veteran.
"I know that one day I will be asked to kill someone. But I am ready for that," Tomy said.
Among the ranks of the BACRIM, the sicarios are viewed with a mix of respect and fear; they are tough but also crazy. However, the toll on them is often high. Some struggle with substance abuse, even taking drugs to prepare for a hit, and are haunted by the faces of those they kill. Others display little remorse for what they have done. But between the weight of their actions, the pressures of the law and the organization and the pull between social power and isolation, it is often a short and disturbing career.
The BACRIM sicarios do not operate alone but are part of a team, each member of which has their own functions and responsibilities. Until recently, the Caucasia murder network comprised of more than 25 people, but many of them were recently detained in a police roundup.
The first stage of any hit is to gather intelligence on the target. While the campaneros usually perform this task, in the case of high profile or well-protected targets, it may also involve obtaining high level information from contacts in the security forces, local institutions or businesses.
The sicarios are only armed for the duration of the hit, so their first task is to meet with the "guarda armas," or weapons person. In Caucasia, there are two .38 caliber pistols and a 9 mm revolver at the sicarios' disposal. There are two women who act as the guarda armas. They keep the weapons hidden, but ensure there is easy and quick access at all times.
On the day of the hit, the campanero will often coordinate the action, informing the "piloto" -- the getaway driver -- where to meet the guarda armas and then where to find the target.
The murders themselves often take place in public with little regard for who may be watching. Sicarios know most witnesses are too scared to talk. A lack of police, an easy escape for the sicario and no escape for the victim are their main concerns. The piloto will take the sicario near enough to the scene to identify the target, then wait with their motorbike engine running. The sicario will take the victim down with preliminary shots then, if there is the opportunity, finish them aiming at the head before re-joining the piloto and making their escape.
There are numerous ways someone may find themselves a target of the BACRIM. Their territorial and criminal monopoly must be maintained by brutally policing the slightest of challenges to their authority.
Any unauthorized drug sales, even at the lowest levels of street dealing, can result in a death sentence. Any member of the BACRIM caught stealing or running sideline activities such as using the Urabeños' name to run their own extortion rings is similarly punished by death. Any business owner that defies their extortion demands or other criminal operations will also find themselves a target.
Also key to maintaining control is the policing of "sapos," or snitches. Informants, whether members of the organization, rivals or civilians, represent a serious risk to both the BACRIM members themselves and their economic interests.
People who are a thorn in the BACRIM's side, such as crusading journalists and politicians, or incorruptible police and judges, also often end up on death lists. As such figures are often well-protected and their removal is not always a matter of urgency, commanders will put a bounty on their head, which any sicario from inside or outside the organization can collect.
The BACRIM also carry out "social cleansing" campaigns informed by a combination of their warped moral and religious code and a desire to assert their authority and intimidate the population.
The arrest of alleged Caucasia Sicario alias "Taison"
Rapists and thieves -- aside from the BACRIM crews that steal motorbikes to use in hits and resell -- face an instant death penalty. Drug addicts -- despite being the BACRIM's own customers -- are often murdered, and the LGBT community is routinely threatened, although there have not been murders proven to be directly related to social cleansing of members of the LGBT community in recent years.
In several communities across Bajo Cauca, citizens report how the BACRIM also act as de facto judge and jury in family or neighborly disputes. The commanders hand down sentences, but the sicarios do the work. Other civilians are killed in personal revenge attacks for having crossed a BACRIM member, or their family or friends.
However, the BACRIM's victims are not only those who offend the organization. They also provide sicario services to anyone with the right connections and money.
Among their clients are politicians and prominent members of the region's social and economic elites as well as more common citizens who move in the right circles. Many have access to sicario services through the voluntary protection payments they make to the BACRIM, while others may make contact to place a bounty on the head of a rival or someone threatening their political or business interests. Yet more seek out the BACRIM's services for crimes of passion, often to pay a hitman to take revenge on the lover of their unfaithful wife.
*Reported by James Bargent and Mat Charles. Filmed and edited by Mat Charles. Additional filming by Sven Wolters.