The Trump Organization has relied on manual labor from a crew of Latin American employees that includes many undocumented immigrants for nearly two decades, The Washington Post reports. The workers built fountains, waterfalls, sidewalks, and rock walls across Trump’s various properties and were reportedly nicknamed “Los Picapiedras,” Spanish for “the Flintstones,” due to their handy work with heavy stone. Jorge Castro, a 55-year-old immigrant from Ecuador who was living in the U.S. illegally and worked at seven of Trump’s properties, told the Post Trump “doesn’t want undocumented people in the country,” but still has them at his properties. “If you’re a good worker, papers don’t matter,” Castro, who left his job in April, said. Edmundo Morocho, an immigrant who worked for the Trump construction crew, said he was told to purchase fake identification documents on a street corner, and said that at one point he hid in the woods while labor officials were visiting a Trump property.

The Trump administration, which recently rounded up over 600 suspected undocumented workers, has been notoriously opposed to illegal immigration, with the president using incendiary words like “invasion” to describe the situation at the U.S.-Mexico border. Lawmakers have previously called on the FBI to investigate claims that the Trump Organization has knowingly and routinely hired undocumented immigrants.