The US Treasury Department sanctioned a Sierra Leonean man, Abdul Karim Conteh, on Thursday for his suspected involvement in a large-scale migrant smuggling operation.

Conteh is accused of smuggling thousands of migrants from Asia and Africa into the United States.

According to the Treasury Department, Conteh’s organization provided migrants with false documents, transportation to the US border, and advice on how to cross illegally. Their network reportedly extended to Nicaragua, a Central American nation known for lenient visa requirements that make it a popular route for smugglers.

The smuggling ring catered to individuals from a dozen countries, including China, Iran, Russia, Somalia, and Nigeria.

Conteh was apprehended in Tijuana, Mexico on July 11th. US authorities are currently seeking his extradition on federal migrant smuggling charges. The Treasury Department also sanctioned Conteh’s Mexican wife, Veronica Roblero, alongside two other individuals from Sierra Leone and Togo believed to be part of the smuggling ring.

The Treasury’s Office of Foreign Assets Control, tasked with combating financial crimes, alleges the group laundered money earned from their smuggling activities. The sanctions imposed by the US freeze any assets the targets hold within the country and bar American citizens from engaging in any transactions with them.