Following the breakup of Yugoslavia in 1991 and the decade of ethnic conflict that followed, drug traffickers in the Balkan states built thriving smuggling operations out of the chaos. When peace settled over the region in the early 2000s, some of them headed to Latin America in search of new opportunities.

There they built alliances with powerful crime groups, including the Revolutionary Armed Forces of Colombia and Brazil’s First Capital Command, to help them source and transport cheap cocaine, counter-narcotics officials said.

Their gradual mastery of the trans-Atlantic smuggling route was aided by maritime know-how gained through centuries of Balkan seafaring. Thousands of men from the region work on cargo ships, some of whom have proven susceptible to corruption or coercion, according to counter-narcotics authorities, police reports and court documents.

Balkan traffickers bribe or threaten Balkan sailors to tamper with shipping containers, stash cocaine in their belongings, or haul it onto their vessels from smaller boats while out at sea.

Back on land, criminals within Europe’s Balkan diaspora community have provided distribution and retail infrastructure for street sales, giving the Balkan Cartel a presence along the entire supply chain, authorities said.

Slobodan Kostovski, the jailed Serb, was part of the first wave of these gangsters to bet his future on Latin America, according to Brazilian police.

He came onto their radar in 2006, following a tip from German cops, according to the 3,025-page Operation Niva report prepared by Brazil’s federal police. By then, Kostovski had compiled “a very long criminal record” that included armed robbery, manslaughter and jailbreaks in Sweden and the Netherlands, according to a 1989 ruling by the European Court of Human Rights.

After landing in Latin America, Kostovski smuggled cigarettes from Paraguay before expanding “to other illicit activities such as drug and arms trafficking and money laundering,” according to a previously unreported US intelligence report.

By 2006, he had established himself in the coastal city of Vilha Velha, near the port of Vitoria. There he lived in a beachside apartment with his Brazilian wife and their son, according to the Operation Niva report.

Kostovski’s decision to settle in Brazil was no accident, law enforcement officials said, given its extensive coastline and proximity to cocaine-producing nations.

“There was a concerted strategic effort early on to send representatives of various Balkan Cartel groups to South America to settle down, to make roots, to marry locals,” the ex-DEA official said. “Eventually many of them became promiscuous brokers” of cocaine.

Kostovski travelled frequently, using passports with fake names that made his movements difficult to track, according to the US and Brazilian intelligence documents.

The ex-DEA agent said police around the world were slow to recognise how big Balkan players had become, in part because these traffickers excel at hopping between jurisdictions on phony documents. An epic bust made clear they were a force to be reckoned with.

In June 2019, US authorities seized around 18 metric tonnes of cocaine – worth over $1 billion – hidden aboard a cargo vessel named the MSC Gayane. The Rotterdam-bound ship had docked in Philadelphia after a voyage to Latin America.

The seizure, one of the largest cocaine hauls in US history, revealed just how deeply Balkan cartels had burrowed into the ocean shipping industry and specifically the Mediterranean Shipping Company, the vessel’s owner. Known as MSC, the Geneva-based firm is the world’s largest shipping company. It’s also a major employer of Balkan seamen and operates a crew training centre in Montenegro.

Eight MSC Gayane crew members – including five Montenegrins and a Serb – were ultimately convicted of smuggling the cocaine in an audacious nighttime operation that involved hauling drugs onto the vessel from trailing speed boats. Lawyers for the convicted Balkan seamen either didn’t reply or declined to comment.

Goran Gogic, a Montenegrin former heavyweight boxer whom prosecutors allege was the chief logistician behind the shipment, is currently jailed in New York City awaiting trial. His lawyer, Joseph Corozzo, said Gogic maintained his innocence.

MSC said cocaine smuggling was “an industry-wide issue requiring an industry-wide response.” The company said it had strengthened security measures after the 2019 incident with tens of millions in annual investments, including in technology. All of its contractors are thoroughly vetted, MSC added.

Previously unreported Brazilian police documents show Balkan gangsters had been targeting MSC ships in South America for over a decade before the big US bust.

In September 2010, federal police working the Operation Niva probe seized 29 kilos of cocaine hidden in bags of groceries carried by two Montenegrin seamen as they attempted to board their cargo ship, the MSC Sandra, which had docked in the Port of Paranaguá in southeastern Brazil.

The sailors, Dragan Jovanovic and Vladimir Bulajic, were convicted and sentenced to nine and a half years in prison in São Paulo state. So was Boris Perkovic, the Brazil-based Montenegrin whom prosecutors said supplied them with the drugs.

Balkan cocaine traffickers have infiltrated the ocean shipping industry to move their loads, authorities say. Montenegro-born Boris Perkovic, shown in these June 4, 2009, surveillance photos from Brazil’s federal police, was convicted in Brazil for trying to smuggle 29 kilos of cocaine aboard a cargo ship with the help of two Montenegrin seamen employed on the vessel. Federal Police of Brazil via Reuters

Perkovic – whom police said also worked with Kostovski’s crew in Vilha Velha – was released in 2018 and died two years later, according to records from Brazil’s federal and state courts. Reuters was unable to reach Jovanovic and Bulajic, who are now free. MSC declined to comment on the case.

The company’s ships were also at the heart of Kostovski’s trafficking scheme, according to the Operation Niva report.

From his base in Espírito Santo state, Kostovski and his crew hatched a plan to piggyback on one of the region’s top exports. The state is the capital of Brazil’s ornamental stone industry, shipping boatloads of marble and granite slabs around the world. Kostovski and his team planned to hollow out the blocks, hide cocaine in the recesses, then ship them to Eastern Europe, the Operation Niva report said.

• A Reuters report