It reads like an espionage novel: Hell-bent on a deadly mission, she bribes an immigration official to slip out of the country under the radar. From there, she fakes a passport and gets on an international flight. And then another, at which point she vanishes. But not before a terrorist attack that devastates the City of Light.

This scenario, of course, is not fiction. Some time before terrorists slew their way through Paris, Seham Al Salkhadi bribed a group of immigration officials and members of the judiciary police in Colombia to the tune of $1,500 and boarded a flight to the French capital using a fake Israeli passport. From Paris, the Syrian woman boarded a flight to Stockholm and vanished. Authorities from Colombia and France are still trying to track Al Salkhadi down, uncertain as to what role, if any, she played in the attacks in Paris last November.

Certainly, the route to France from Syria via Colombia is convoluted, but it is not all that uncommon. In 2015, 28 Syrians were found to be in Colombia illegally and were quietly deported, according to information released in November by government authorities. Such numbers are too small to be really noticed among the 6,600 people the South American country deports every year. But Colombia, and other countries in Latin America, are now paying more attention to patterns and the flow of people that may have gone unnoticed in the past.

These pockets of radicalism are out there, and it is [imperative] to keep them monitored. Roman Ortiz, founder and director of Decisive Point

Most illegal migrants who make their way through the region are en route to the U.S., typically looking for whatever work they can find. Increasingly, however, Colombian authorities worry about people (including some with links to extremist groups) from Nepal, India, Pakistan or Syria using these flows to move through the region or make contact with sympathizers without attracting notice. More and more, there are concerns that terrorists, affiliated or not with the Islamic State, could move through Colombia, as well as places like Venezuela and Guatemala, ending up in Mexico and then crossing into the U.S., or head elsewhere in the world the way Al Salkhadi did — all with relative ease.

ISIS dominates the fears of many, but amid blanket fears, not everyone recognizes that terrorist groups like it strategize territories in chillingly savvy ways. “Islamic State is clearly trying to build structures in the United States, but clearly this has nothing to do with the Mexican border because they do not need it,” Roman Ortiz, the founder and director of Decisive Point, a Colombian firm that works with governments and major corporations and provides national security and defense consulting services, told OZY. “The Mexican border obviously is a door, but I don’t think it’s the most important.” There are indications that in some areas of Latin America, such as Trinidad and Tobago, there is a growth of Islamic radicalism, adds Ortiz. “It is local people who have gone to Iraq and Syria to fight with ISIS … These pockets of radicalism are out there, and it is [imperative] to keep them monitored.”

Unchecked migration could make the monitoring of radicalism’s growth very difficult. Colombian authorities, which did not respond to requests for comment, say it can cost as much as $12,000 to reach the U.S. through Central and South America. In some cases, migrants might be involved in prostitution or drug smuggling to pay off the debt to the individuals or cartels that facilitate the migration. And links between these cartels and extremist groups are a cause for concern, particularly since they are not without precedent. In 2011, for example, the FBI uncovered a plot between the Los Zetas drug cartel in Mexico and extremists in Iran to kill Saudi diplomats. In another incident, U.S. authorities dismantled a Colombian-Lebanese money-laundering organization actively working for Hezbollah.

For now, the world is more focused on the refugee crisis in Europe. It’s a good thing to be focused on, but there’s a sobering downside: Very little attention is being paid to this particular route. That includes people of any stripe — from hardworking families in search of a better life to terrorists looking to move undetected into countries they may be targeting. This may be a dangerous mistake. There are countless migrants stranded across Latin America and the Caribbean. At this very moment, there are several thousands of Cubans looking to make their way to the U.S. who are stuck in one country or another as they flee the Castros’ regime, according to the Pew Research Center, a nonpartisan think tank in Washington, D.C. Some 43,159 Cubans entered the U.S. in 2015, according to U.S. Customs and Border Protection data that Pew acquired after a request for records. That figure is up 78 percent from the 24,278 Cubans who entered the U.S. in fiscal year 2014. Figures from Migración Colombia, that country’s immigration agency, show that 3,194 Cubans were caught in Colombia illegally during the first eight months of 2015.

And the numbers are still rising. According to Migración Colombia, from January to May, 2016, about 6,000 illegal immigrants were detected by authorities in the South American country. More than 3,800 of them were located in the town of Turbo, the last checkpoint before the border with Panama. Today, more than 100 Cubans are stranded in a warehouse in Turbo waiting for a solution so they can continue their journey to the U.S. “From the beginning, we have respected the rights and integrity of each of these migrants,” Christian Krüger, head of Migración Colombia, said in a press release. The release adds that Migración Colombia and the national government do not provide transportation to any location other than the border where they entered Colombia or their place of origin, “because otherwise we would be contributing to these criminal gangs.”

Although this crisis is under the radar, not everyone has ignored it. “I urge the countries of the region to redouble generously every effort to find a rapid solution to this humanitarian tragedy,” said Pope Francis late last year as he called on Central American countries to assist migrants, especially those fleeing Cuba. Two days later, a group of governments in the region reached a deal to fly 8,000 Cuban migrants out of Costa Rica and into El Salvador, from where they could conceivably make their way to Mexico and the U.S.

The flow of people remains — and remains virtually unchecked.