A Trump-connected nonprofit has warned Gov. Maura Healey and Mayor Michelle Wu that it has identified the Bay State and Boston as sanctuaries for illegal immigrants, urging them to undo the policies that it says “make a mockery of American democracy.”

America First Legal Foundation, a national, nonprofit working to promote the rule of law in the US, wrote to Healey and Wu the day before Christmas Eve, emphasizing refusal to cooperate with federal immigration enforcement is a crime.

The letter came the same day the Herald reported that Healey admitted the “overwhelming” cost of housing migrants doesn’t equate to being an anti-enforcement “sanctuary.”

America First Legal, however, pointed to a comment Healey made on national television a day after President-elect Donald Trump’s victory, vowing that Massachusetts State Police wouldn’t assist in mass deportations.

“Every tool in the toolbox is going to be used to protect our citizens,” the governor told MSNBC anchor Lawrence O’Donnell on Nov. 6.

“This rhetoric illustrates the Commonwealth’s intent to blatantly violate federal law,” America First Legal Senior Counsel James Rogers wrote to Healey. “Accordingly, we are sending this letter to put you on notice of this risk and insist you comply with our nation’s laws.”

In his letter to Wu, AFL highlighted how the mayor declared in November that Boston would continue to protect immigrants in “every possible way” under the threat of mass deportations and would not cooperate with efforts that threaten residents’ safety.

AFL is led by two high-ranking officials under the previous Trump administration: Stephen Miller, a senior advisor to the president, and Gene Hamilton, counselor to the Attorney General at the Department of Justice.

In Massachusetts, officials at the state and local levels have pointed to a 2017 ruling from the Supreme Judicial Court that bars police from detaining a person solely on the basis of their immigration status. This decision has since been used to prohibit interactions with federal immigration officials.

AFL detailed how the federal government has authority over immigration and federal law preempts state and local law restricting officials from communicating with the feds about an individual’s immigration status.

The nonprofit also warned that sanctuary policies could expose Healey, Wu, and their “subordinates,” to criminal liability for conspiracy to commit a federal offense and to impede a federal officer. They also risk potential personal financial liability to private plaintiffs.

“The American people have spoken through their representatives,” Rogers wrote. “Your jurisdiction’s sanctuary laws or policies therefore make a mockery of American democracy and demonstrate a shocking disrespect for the rule of law. For these reasons alone, you should abandon them.”

In her interview with the Herald last week, Healey said she believes “violent criminals should be deported if they’re not here lawfully” and that local, state, and federal law enforcement should work together to investigate and prosecute crimes and remove people from the country who are criminals.”

But the first-term Democrat said she does not back “showing up at a hotel, and rounding up groups of people who are suspected to be here unlawfully, who are here working, and just deporting all of them without a process.”

Trump’s mass deportation plan will likely be subject to litigation and other legal fights, Healey has said. As attorney general, she sued his previous administration nearly 100 times.

Todd Lyons, a top national official for U.S. Immigration and Customs Enforcement’s Enforcement and Removal Operations (ICE/ERO), told the Herald earlier this week that Massachusetts “can do more to remove egregious foreign-born public safety threats from our neighborhoods by simply notifying ERO when they are in custody.”

The Boston City Council voted unanimously earlier this month to reaffirm the city’s sanctuary commitment under its Trust Act, “promoting trust between local law enforcement and immigrant communities.”

Wu’s comments caught the attention of Trump’s incoming border czar Tom Homan, who bashed the mayor for what he saw as her vow to fight federal efforts to eradicate public safety threats, leading to a public squabble between the two.

America First Legal finished its letter to Healey and Wu, saying: “No matter your views on our Union, the fact of the matter is that you and the other officials who support or enforce sanctuary laws, policies, and regulations have a very personal stake in the matter – you each could face criminal prosecution and civil liability for your illegal acts. We urge you to do the right thing, protect your citizens, and comply with federal law.”

President-elect Donald Trump speaks during a news conference at Trump Tower earlier this year in New York. (AP Photo/Julia Nikhinson, File)