Students pass Rouss Hall and Robertson Hall, left, and Old Cabell Hall, right, at the University of Virginia. (Norm Shafer/For The Washington Post)

The first conclusion to a four-year federal probe of sexual violence at the University of Virginia was issued in secret, and it stood for just four days.

Among its findings was that U-Va. “abdicated” its legal responsibility to act on reports of sexual violence within the school’s powerful Greek system and took a “hands off” approach, relying instead on fraternities to police their own membership in cases of alleged rape and other alleged sexual assaults. It also detailed numerous accounts of alleged sexual assault on the Charlottesville campus, tallied more than 150 cases of possible sexual harassment or sexual violence during a six-year period, and said the university failed to identify and address a “sexually hostile environment.”

That stern criticism of Virginia’s flagship public university was part of a 39-page letter to U-Va. officials presenting the findings of a U.S. Education Department Office for Civil Rights, or OCR, investigation that began in June 2011. The Aug. 31, 2015, letter came amid weeks of feverish maneuvering behind the scenes, with Virginia’s governor and two U.S. senators lobbying on behalf of the school amid concern about the effects of a lashing from the federal agency.

Then, the letter was buried.

A senior education official withdrew it on Sept. 4, after the university said it was riddled with inaccuracies. It remained secret until The Washington Post recently obtained a copy through the federal Freedom of Information Act.

What the public was shown Sept. 21 — when the department and the university jointly announced a resolution — was a shorter and milder letter of findings that became the final word on the investigation. Exactly why the changes were made, and what influence the pro-U-Va. lobbying had on the process, remains unclear. The end result was a verdict that faulted the university’s record on sexual violence but was less harsh than the first version.

The university said the Aug. 31 letter “included significant factual errors,” but it declined to elaborate. A senior Education Department official said she pulled the letter back because she learned more documents were needed to substantiate its assertions.

“It was purely for accuracy reasons,” said Catherine E. Lhamon, assistant education secretary for civil rights. “The reason I withdrew it is I don’t stand by it. . . . I’m a neutral arbiter. I need to go where the facts lead me.”

A student passes the Harrison Institute and Small Special Collections Library at the University of Virginia. (Norm Shafer/For The Washington Post)

Like the first letter of findings, the final version from OCR said that the university violated the anti-discrimination law known as Title IX and pointed out numerous flaws in the school’s response to sexual-assault reports during a multiyear period.

But the second letter — 13 pages shorter — did not include several accounts of possible sexual assault that had been listed earlier, significantly softened references to fraternities, hedged some criticism of U-Va. and put much less emphasis on total counts of reports of sexual violence at the elite public school.

The first letter counted 158 reports of possible sexual harassment or sexual violence at U-Va. from 2008 through the fall of 2014, “including rape and gang rape,” and it faulted the handling of 41 percent of them. The letter highlighted this total in the summary and conclusion.

The second letter narrowed the time frame, finding 50 informal reports of possible sexual harassment, including sexual violence, from fall 2008 through spring 2012. In 22 of those cases, all but one involving alleged sexual assault, the second letter found that the university failed to take appropriate action. It also noted government concerns about U-Va.’s response in 29 of 87 informal reports of incidents from fall 2012 through December 2014.

None of those numbers were included in the letter’s summary or conclusion.

On fraternities, the Education Department originally charged that U-Va. “abdicated its Title IX responsibilities with regard to reports of sexual harassment including sexual violence that were raised against students in the Greek system, instead relying on fraternities to investigate and sanction students themselves.” It said that the university took a “hands off” approach to responding to complaints of sexual violence committed by fraternity members.

The second letter was not as blunt. It said that in at least two instances in 2013 and 2014, “the University did not promptly investigate information in cases that involved fraternities.” The letter also noted that the files in those cases “do not reflect the University evaluating steps necessary to protect [the] safety of the broader University community.”

The shift in language and tone is notable in part because fraternities form a powerful constituency at U-Va. and many other universities, on campus and among alumni, and they often are at the center of debates about how best to curtail sexual assaults on the nation’s campuses.

Also among the differences:

●The original findings were packed with sobering data and anecdotes, including case studies of 13 informal student reports of possible sexual misconduct. Several involved alleged sexual assault or rape. Many details were redacted in the version that the federal government provided to The Post, but these narratives generally faulted U-Va.’s response.

One narrative, labeled “Student Report #2,” said: “The University then took an entire year, with periods of three months and six months between contacts with the complainant, to determine that the University had an obligation to act, despite the complainant’s request for no action. To date, it is unclear whether the University took any action or had merely determined that it had an obligation to do so.”

The Sept. 21 letter omitted the 13 narratives.

●The first letter asserted that the chair of the university’s ­sexual-misconduct board, which adjudicates complaints against alleged attackers, had a conflict of interest because she had multiple roles on campus. An associate dean of students, she was often a first point of contact and support for students who were considering filing sexual-assault reports.

Later, the government hedged this criticism, saying that the multiple roles created “the appearance of a conflict of interest.”

●In its summary, the first letter stated flatly, “During the period of its investigation, OCR also found that the University failed to identify and address a sexually hostile environment.”

The second letter’s summary on this point was more nuanced. It found that “a basis for a hostile environment existed for affected students at the University and that the University failed to eliminate a hostile environment and take steps to prevent its recurrence during academic years 2008-2009 through 2011-2012, as well as concerning a report filed by a student in 2013 and a report filed by a student in 2014.”

These letters and other documents The Post obtained provide a rare window inside the Obama administration’s efforts to crack down on campus sexual assault. And they show the vehement efforts that U-Va. took to push back against enforcement methods and conclusions the school deemed unfair.

Columbia University has released its report on Rolling Stone’s retracted story detailing an alleged rape at a University of Virginia fraternity. The Washington Post’s T. Rees Shapiro, who first reported inconsistencies in the Rolling Stone article, explains the key findings in the report. (Gillian Brockell/The Washington Post)

As the investigation was nearing completion, U-Va. was at the center of turmoil over college sexual assault. The school had been rocked in the fall of 2014, when Rolling Stone magazine published an account of an alleged gang rape at a U-Va. fraternity and depicted the university as indifferent to the issue, an accusation U-Va. officials strenuously denied. The gang-rape account unraveled after The Post revealed significant discrepancies in it. Although the magazine ultimately retracted the article, the episode took a toll on the university’s public image.

Virginia Gov. Terry McAuliffe (D) cited the Rolling Stone fiasco in an Aug. 14 letter to then-Education Secretary Arne Duncan, saying that he worried that information federal investigators gathered before the article was retracted, in April, “could have been influenced by the atmosphere unfairly created on campus by that false article.”

Sens. Timothy M. Kaine and Mark R. Warner, both Virginia Democrats, also wrote Duncan on Aug. 25 to echo McAuliffe’s plea for fairness to U-Va.

Lhamon, the assistant education secretary, denied that political pressure played any role in her decision to withdraw the first letter. “The findings did not get watered down,” she said. “As I’ve said in the past, the university did not want us to make the findings that we made. We made them in both letters.”

Lhamon said it was not the first time that the Office for Civil Rights has withdrawn a letter of findings. But she declined to say how often it happens.

U-Va. officials declined to be interviewed about the newly obtained documents, including the Aug. 31 letter.

“This letter included significant factual errors and presented findings based on factual inaccuracies,” the university said in a statement. “We are profoundly disappointed that the Department of Education publicly released a factually inaccurate letter that it previously withdrew due to an incomplete review of available information. This letter does not represent the final outcome of the Office for Civil Rights compliance review. . . . The University remains focused on implementing substantive initiatives aimed at providing a safe learning and living environment for every member of its community.”

Across the country, OCR investigations have proliferated since the administration warned schools in April 2011 that they were responsible, under Title IX, for investigating and resolving sexual-violence reports. Evidence has mounted that the violence is widespread.

A Washington Post-Kaiser Family Foundation poll last year found that 20 percent of young women who attended college during a four-year span said they had been sexually assaulted; surveys at prominent U.S. universities have found similar results.

As of Feb. 26, federal investigations related to sexual violence were underway at 167 colleges and universities, according to the Education Department.

The investigations can last years. In most cases, almost everything about them is confidential until the end, unless students involved in a related incident opt to go public.

Closing a case often requires a letter of findings from the government and a signed resolution agreement in which the school pledges to take steps to prevent and address sexual assault.

The U-Va. investigation had entered its fifth year when the government and the university hit an impasse last summer over how it would be resolved. U-Va. officials, based on their talks with federal investigators, worried about how their school would be portrayed, according to documents The Post obtained. They insisted on seeing a letter of findings before signing a resolution, but the government declined to provide an advance copy, according to the documents.

On Aug. 20, U-Va. President Teresa A. Sullivan wrote Duncan to lament the impasse.

“Over the next week, 23,000 students will be returning to Charlottesville to begin a new academic year; the fact that we have not been given the courtesy of reviewing OCR’s written findings makes it impossible for us to prepare our University community adequately for what lies ahead in our process with OCR,” Sullivan wrote in a three-page letter. “This predicament is uniquely damaging to us, as our community is still recovering from Rolling Stone’s reckless journalism and now-discredited story.”

Carr’s Hill is the residence of the University of Virginia president, Teresa A. Sullivan. (Norm Shafer/For The Washington Post)

U-Va. officials that day also sent Duncan, Lhamon and Undersecretary Ted Mitchell a 41-page memo strongly criticizing OCR’s procedures and arguing against a possible finding that the school had a broad “hostile environment” regarding reports of sexual harassment or sexual violence.

“If there were concerns about the environment at the University, OCR’s failure to share compliance concerns with the University during the review, and its radio silence for nearly one and a half years of that review, contributed to any such environment and allowed issues to persist unabated for a four-year period, under OCR’s watch,” the university wrote.

Eleven days later, the government issued its blistering first conclusion, which was short-lived.

Emails between the government and the university show the final 19-page resolution agreement was the product of extensive negotiation. One significant pledge that U-Va. made was to review its written agreements with fraternities and sororities to ensure they are aware the university is authorized to investigate reports of sexual violence made against their members and mete out appropriate punishment. The government’s intent with this measure, read alongside the Aug. 31 letter, seems clear: There will be no abdication of university oversight of the Greek system in Charlottesville.

A final round of negotiation occurred over a joint news release. The two sides exchanged drafts. One of OCR’s last edits inserted the word “fraternities” into the news release in a line that noted “instances in which the university did not promptly investigate information in cases that involved fraternities.” U-Va.’s preferred term had been “student organizations.”

Lhamon explained her view in a Sept. 19 email to the U-Va. general counsel, Roscoe Roberts: “We think it is important to reference fraternities, as distinct from student organizations, because it is fraternities about which we have concern.”

Students pass on the lawn at the University of Virginia. (Norm Shafer/For The Washington Post)