A growing number of Colombian mercenaries have been working for Mexican drug cartels.

Spain’s El País recently ran an English-language article on the topic.
From the article:
“The growing presence of former Colombian military personnel in Mexico has authorities on edge. Last week, Claudia Sheinbaum’s administration reported the arrest of 12 Colombian citizens in connection with the deaths of eight soldiers from an antipersonnel mine in Michoacán, in the center of the country. Nine of those arrested are former military personnel, while the other three had received military training.
This case adds to other recent incidents in the region, where authorities have linked Colombian citizens to drone bomb attacks. In Guanajuato, local police claim to have identified ‘Colombian paramilitaries, lancers, and explosives experts.’ ”
And it’s not just in Mexico:
“Hundreds of former Colombian soldiers are leaving their country each year to fight in foreign conflicts, such as the war in Ukraine, attracted by high salaries. ‘To put this into perspective, in 2008, in Latin America alone, there were 12,000 mercenaries, and by 2018, the number was estimated at 2.4 million,’ says Paloma Mendoza Cortés, a professor and expert in national security at ITAM, one of Mexico’s most prestigious universities. ‘Most of them are of Colombian origin, and for many years the government denied their existence. It’s a surprising phenomenon and one that has a decisive influence that helps explain the increase in the firepower of organized crime.’ ”
“In Mexico, the CJNG and other groups offer large sums to mercenaries to fight in an extremely violent environment. In each of the last eight years, Mexico has recorded more than 30,000 murders, most of them committed with firearms. Drug trafficking to the United States, the illegal flow of weapons southward, and the mafia-like practices of criminal groups, immersed in thousands of battles to control entire regions, exacerbate the violence.”
Colombians work for different cartels and so have probably wound up fighting each other in Mexico.
Why are Colombians in such demand as mercenaries?
“Colombians are highly valued in the military contractor market overseas. Andrés Macías, a member of the U.N. Working Group on the use of Mercenaries, explains that this is due to their ‘extensive experience’ in counterinsurgency combat. ‘The level of training of the Colombian military is very high and almost comparable to that of the United States. Furthermore, a regular soldier can retire at 40. In other words, at a young age, people can accumulate up to 20 years of military experience in one of the most highly trained armies in the world,’ he points out.”
It usually boils down to the money.
“The most common reason former military personnel give for becoming mercenaries — in more than a dozen countries such as Ukraine, Russia, Yemen, and the United Arab Emirates, among others — is the meager retirement pay they receive as veterans. Offers from security companies, foreign militaries, and now cartels are also pushing many to fight in foreign conflicts.”
“The lure of earning up to five times more has led many to fall into traps, as several Colombian groups have reported, such as those who fought with Sudanese paramilitaries or those currently facing prosecution for the assassination of Jovenel Moïse in Haiti. ‘Many are offered a contract to perform specific activities and are then forced to do others. This is what is known as predatory recruitment,’ explains Macías. Being in an unknown country, often without their own money or documentation, recruits are vulnerable to falling entirely into the hands of these mercenary networks.”
“Colombian President Gustavo Petro, along with his administration, has promoted a law against mercenarism to prohibit an activity that ‘exploits retired military personnel.’ Those involved in the business blame the Colombian government for failing to protect veterans so they can adapt to civilian life.”
Nor do Colombian mercs necessarily travel directly from Colombia to Mexico. The article quotes a 31-year old Colombian military veteran in Mexico who tells how he got there: “I was in Ukraine for a few months. Many of us created TikTok accounts where we showed our daily lives. The cartels contact you through them.”
The cartel offered this individual 2,000 dollars a month and offered to transport him and others from Warsaw, Poland to Mexico. ” ‘Leaving from Colombia is more difficult’, he said, ‘You have to cross the Darién River with fake passports, and now, with the security Panama has put in place, it makes you think twice,’ he notes.”