President Trump has shown he is willing to take dramatic steps to stop the flow of illegal immigration into the United States, but his administration has been silent about one company that long relied on unauthorized labor: Trump’s own business.

Democrats in Congress have been stymied in their efforts to find out whether federal authorities are investigating the Trump Organization over its reliance for years on workers without legal status — to cut grass, clean rooms and cook meals at golf courses in New York and New Jersey.

The Washington Post has interviewed more than 30 people who worked for the Trump Organization without legal status, some for more than a decade. Some also did personal jobs for Trump’s sons. In response to these and other reports, the Trump Organization pledged to better vet its workforce.

The latest rebuff to Democratic lawmakers came this week. Immigration and Customs Enforcement missed a Tuesday deadline to respond to a request from House Homeland Security Committee Chairman Bennie Thompson (D-Miss.), asking whether an investigation had been opened into the hiring practices of the president’s company. ICE said only that it wouldn’t meet the April 9 deadline, a Thompson spokesman said.

It was just the latest effort by congressional Democrats to provoke action against Trump’s company. Last month, congressional Hispanic Caucus members criticized the “apparent failure” of the Department of Homeland Security to investigate the Trump Organization about the issue. Before that, Sen. Robert Menendez (D-N.J.) wrote in February to the FBI and DHS about the “serious nature of these allegations.”

And on Tuesday, Rep. Raúl M. Grijalva (D-Ariz.) complained about the lack of response to his own letter to the FBI.

“I sent a letter to the FBI demanding an investigation into the Trump Organization’s dubious employment practices and have yet to receive a response,” Grijalva wrote on Twitter. “It’s unacceptable to demonize immigrants while exploiting their labor for personal profit.” 

The silence comes as Trump has turned his attention back to his signature issue — illegal immigration — amid a burgeoning crisis at the border. Frustrated with the record number of families from Central America turning up at the border to seek asylum, Trump ousted his Homeland Security secretary and other leaders in the department this week in an effort to install a more aggressive team.

White House officials declined to answer questions about Trump’s use of undocumented labor, and ICE did not respond to requests for comment this week.

Asked in January about what Trump thinks should happen to businesses that hire undocumented workers, White House press secretary Sarah Sanders said Trump is “one of the people that’s identified the fact that we have a problem and we should fix our immigration system.”

Trump Organization also did not respond to a request for comment Wednesday. Eric Trump, one of the president’s sons who helps runs the Trump Organization, has said previously that he and other senior executives did not know the company hired unauthorized workers, noting that the employees used falsified documents.

“We have tens of thousands of employees across our properties and have very strict hiring practices,” the company said in December. “If any employee submitted false documentation in an attempt to circumvent the law, they will be terminated immediately. We take this issue very seriously.”

In recent months, the Trump Organization has fired at least 18 undocumented workers at five golf courses, The Post has reported. The New York Times reported additional firings on Tuesday — seven workers at Trump National Golf Club Jupiter in Florida.

“The allegations set forth in numerous reports are truly troubling,” Thompson wrote to ICE deputy director Ronald D. Vitiello in the March 26 letter, obtained by The Post. “Not only do the allegations suggest that these employers were aware of workers’ true immigration status, but also that managers physically and emotionally abused undocumented workers.”

Trump had previously tapped Vitiello, a 30-year veteran of U.S. Border Patrol, to lead ICE but rescinded the nomination last week.

Companies that hire large numbers of undocumented workers regularly attract law enforcement attention. Last week, ICE arrested nearly 300 workers at a technology company outside of Dallas, in one of the largest immigration raids in years. 

“Businesses that knowingly hire illegal aliens create an unfair advantage over their competing businesses,” said ICE Special Agent in Charge Katrina Berger, according to the Associated Press. “In addition, they take jobs away from U.S. citizens and legal residents, and they create an atmosphere poised for exploiting their illegal workforce.”

With millions of undocumented workers in the United States, ICE officials say they must prioritize their investigations. The more important cases involve companies where they can prove bosses knew the workers couldn’t legally work in the United States and hired them anyway, or helped smuggle them into the country or bought them fake documents. 

Many former undocumented workers at the Trump golf courses say their supervisors knew they were undocumented and in some cases spoke with them about the fake social security numbers and green cards they used to apply. 

In an interview, Thompson wouldn’t say whether he plans to use the committee’s subpoena power if DHS doesn’t respond to his questions. 

“The fact that the president of the United States is the owner of this property makes it significant. More than anything else, he’s taken an oath to uphold the laws of this country,” Thompson said. 

“You can rest assured that we will get whatever information that’s available,” he added.  

So far, that’s been meager. 

Menendez has received no response from his letter in February, a spokesman said. 

One congressional aide said that the DHS inspector general’s office wrote back recently in response to a request to investigate ICE’s handling of the Trump case. But it referred the question back to ICE — the same “agency that we have concerns is not doing their job,” said the aide, who spoke on the condition of anonymity to discuss internal committee business.

Democrats in Congress have pushed the Trump administration to protect these workers from deportation and to treat them as potential witnesses to crimes.

Dozens of undocumented workers remain in limbo while they wait to hear if they’ll receive some type of visa or authorization to stay in the country legally.  

“The only thing we have is these letters that the congressmen signed,” said Margarita Cruz, a housekeeping employee from Mexico who was fired after eight years of working at the Trump National Golf Club in Westchester County, N.Y. “It’s just a piece of paper with their signatures.” 

“That’s all we have for protection,” she added. “It’s frustrating.”