Harvard University covered up a high-level investigation into whether its controversial president was a plagiarist — and used an expensive law firm to threaten The Post over our own probe.

The college announced Tuesday morning that it had investigated Claudine Gay over whether some of her academic work was plagiarized and had cleared her of breaching the college’s “standards for research misconduct.”

Instead, it said that she would request four corrections in two publications to insert citations and quotation marks that were originally “omitted.”

But The Post can disclose that Harvard spent weeks failing to come clean about Gay being under investigation — staying quiet even when she was hauled in front of Congress for disastrous testimony on how the Ivy League college is dealing with antisemitism on campus.

Harvard only disclosed the investigation when the university’s governing body, Harvard Corporation, said it unanimously stood behind her despite a firestorm of criticism for her evidence to Congress.

Harvard’s public statement on the allegations of plagiarism came a day after a conservative activist posted questions on X about citations in Gay’s 1997 PhD dissertation.

Dear Members of the Harvard Community, As members of the Harvard Corporation, we today reaffirm our support for President Gay’s continued leadership of Harvard University. Our extensive deliberations affirm our confidence that President Gay is the right leader to help our community heal and to address the very serious societal issues we are facing. So many people have suffered tremendous damage and pain because of Hamas’s brutal terrorist attack, and the University’s initial statement should have been an immediate, direct, and unequivocal condemnation. Calls for genocide are despicable and contrary to fundamental human values. President Gay has apologized for how she handled her congressional testimony and has committed to redoubling the University’s fight against antisemitism. With regard to President Gay’s academic writings, the University became aware in late October of allegations regarding three articles. At President Gay’s request, the Fellows promptly initiated an independent review by distinguished political scientists and conducted a review of her published work. On December 9, the Fellows reviewed the results, which revealed a few instances of inadequate citation. While the analysis found no violation of Harvard’s standards for research misconduct, President Gay is proactively requesting four corrections in two articles to insert citations and quotation marks that were omitted from the original publications. In this tumultuous and difficult time, we unanimously stand in support of President Gay. At Harvard, we champion open discourse and academic freedom, and we are united in our strong belief that calls for violence against our students and disruptions of the classroom experience will not be tolerated. Harvard’s mission is advancing knowledge, research, and discovery that will help address deep societal issues and promote constructive discourse, and we are confident that President Gay will lead Harvard forward toward accomplishing this vital work.

Gay had vigorously defended her academic record in comments to the Boston Globe after the dissertation questions were revealed, and said: “I stand by the integrity of my scholarship. Throughout my career, I have worked to ensure my scholarship adheres to the highest academic standards.”

Tuesday’s statement, issued to “members of the Harvard community” said that the probe began in late October, after Harvard “became aware” of allegations about Gay.

But the statement did not tell the full story — including how Harvard called in bulldog attorneys to protect Gay.

The Post contacted the university on October 24, asking for comment on more than two dozen instances in which Gay’s words appeared to closely parallel words, phrases or sentences in published works by other academics.

The 27 instances were in two academic papers published in two peer-reviewed journals between 2011 and 2017, and an article in an academic magazine in 1993.

The Post was sent the material anonymously and had conducted our own analysis before asking Harvard to comment on whether Gay had plagiarized or failed to properly cite other academics’ work. We have continued to investigate since.

When The Post brought the allegations to Harvard, Jonathan Swain, its senior executive director of media relations and communications, asked for more time to review Gay’s work.

A day later Swain, who was part of the Biden-Harris transition team and a one-time Hillary Clinton aide, said he would “get back in touch over the next couple of days.”

A GIF showing how similar text is in works by Gay and another author

But he did not. And two days later, on Oct. 27, The Post was sent a 15-page letter by Thomas Clare, a high-powered Virginia-based attorney with the firm Clare-Locke who identified himself as defamation counsel for Harvard University and Gay.

The letter contained comments from academics whose work Gay was alleged to have improperly cited — even though the political scientists’ review could only just have begun.

Harvard has still not said what works Gay is seeking to have corrected, and whether her dissertation will be corrected. it did not respond to a further set of questions from The Post Tuesday.

The dates on the three works reviewed by The Post ranged from 1993, when Gay was a post-graduate student, until 2017 when she was Dean of Social Science at the school’s Faculty of Arts and Sciences.

Gay, 53, assumed office as Harvard’s first black president earlier this year.

A GIF showing how similar text is in works by Gay and another author

Jonathan Bailey, who heads up Plagiarism Now, and has worked as an expert witness involving plagiarism cases, reviewed the papers in question and said he believes that some of Gay’s work did violate Harvard’s own academic policy on citations.

“It is a violation of the policy and that alone should justify a thorough examination,” said Bailey in an email to The Post.

Academics whose work appeared startlingly similar to Gay’s differed in whether they felt she had appropriated their work without attribution.

George Reid Andrews, professor of history at the University of Pittsburgh, acknowledged that Gay “did borrow a few of my phrases” in her 1993 article “Between Black and White: The Complexity of Brazilian Race Relations” from Reid Andrews’s paper “Black Political Protest in Sao Paulo, 1888-1988,” which appeared in the Journal of Latin American Studies in 1992.

A GIF showing how similar text is in works by Gay and another author

“But this happens fairly often in academic writing and for me does not rise to the level of plagiarism,” he said. “I am glad she read my work, learned from it, and recommended it to her readers.”

Jens Ludwig, an economist at the University of Chicago, had a similar response when contacted by The Post in October about similarities in a paper he co-authored in 2008 and Gay’s “Moving to Opportunity: The Political Effects of a Housing Mobility Experiment,” published in Urban Affairs Review in 2011.

“We partnered with Claudine on some work and my guess would be that it is the connection,” he said.

A GIF showing how similar text is in works by Gay and another author

Among the papers under scrutiny are 2017’s “A Room for One’s Own? The Partisan Allocation of Affordable Housing,” published in Urban Affairs Review and written while Gay was dean of social science at Harvard.

In the paper, Gay uses phrases which closely parallel ones in a 2011 paper by Anne Williamson, a professor of political science at the University of Miami in Ohio.

Williamson told The Post she was “angry” when she read the excerpts.

“It does look like plagiarism to me,” she said. “If they are going to do what they did, then I should be cited as a reference. My first reaction is shock. The second reaction is puzzlement. There was a way to draw from my paper. All she had to do is give me a credit.”