A new lawsuit is demanding that the Department of Homeland Security release Prince Harry's immigration records, citing suspicions that the Biden administration allowed him to enter the U.S. despite his admission of illegal drug use – a factor that would usually be enough to deny other people entry.

The suit was filed Monday by the Heritage Foundation, which argues that DHS has failed to comply with previous requests for documents related to the agency's decision to let Prince Harry stay in the country.

The Freedom of Information Act requests were made following the release of Prince Harry's bestselling memoir, "Spare," in which he admitted to using cocaine, psychedelics and marijuana.

When filling out a visa application, those drug abuses are supposed to be documented in detail, and would normally trigger a special review if not rejection of the application. However, the group is suspicious that Prince Harry was either not honest on his visa application, or that the Biden administration gave him preferential treatment.

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prince harry and DHS secretary

Prince Harry, left, and DHS Secretary Alejandro Mayorkas.

Prince Harry and his wife Megan Markle moved to Los Angeles in 2020.

Dr. Nile Gardiner, director of the Foundation's Margaret Thatcher Center for Freedom, told Fox News Digital that there is "strong public interest" in DHS releasing the Prince's immigration records and application "so the public can see whether there's any discrepancy between what he outlined in his memoir with extensive drug taking and what he actually put on his application," and also if DHS gave him any preferential treatment.

"Anyone who applies for a U.S. visa has to be absolutely honest and truthful with regard to drug use on their application. And in many cases, foreign nationals are denied a visa based on drug use," Gardiner explained.

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Holding a microphone, Prince Harry speaks to the crowd at the Invictus Games Closing Games in the Netherlands, wearing a dark blue suit and royal blue shirt

Prince Harry revealed that helping people is what drives him. (Chris Jackson/Getty Images for the Invictus Games Foundation)

The lawsuit lists some of those high-profile examples like Kate Moss and John Lennon who had trouble obtaining an American visa because of drug use.

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"It is a perjury offense to misrepresent information on an immigration application. So it's very serious business. The public has a right to know whether or not his application was fully accurate. And whether or not he was given any kind of preferential treatment by U.S. immigration officials," Gardiner said.

The lawsuit said that the "while this case focuses on the widespread public and press interest on the specific issue of whether DHS acted, and is acting, appropriately as regards the Duke of Sussex, it cannot be separated from its broader context."

Prince Harry

Prince Harry, center right, arrives at the Royal Courts Of Justice, in London, Monday, March 27, 2023. (Jordan Pettitt/PA via AP)

"The press and congressional hearing rooms are replete with detailed accusations that DHS is deliberately refusing to enforce the country’s immigration laws and is responsible for the current crisis at the border," it said.

"[T]he broader controversy is so grave that Articles of Impeachment have been filed against DHS Secretary Alejandro N. Mayorkas and Secretary Mayorkas has taken the extraordinary step of retaining private counsel to represent him in impeachment proceedings," it said.

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The case was filed in Washington, D.C. District Court.

The DHS did not immediately respond to Fox News Digital's request for comment.