Nine years ago, law professor Lloyd Cohen filed a federal civil rights complaint alleging racial discrimination in admissions to Fairfax County’s prestigious Thomas Jefferson High School for Science and Technology.

But he didn’t argue that the system was biased against black and Latino students, as the Fairfax chapter of the NAACP and a local advocacy group alleged in a similar complaint filed Monday with the Department of Education. African American and Latino students make up 4 percent of the rising freshmen at Thomas Jefferson, or TJ, but make up 32 percent of the county’s entire student body.

Instead, Cohen contended that it was white students who were losing out, the deck stacked against them as the school system sought to boost black enrollment at the high-flying school.

Fairfax officials reject that accusation. The school system “was not discriminating against whites in the admissions process,” spokesman John Torre wrote in an e-mail.

Federal authorities ruled on Cohen’s complaint in a letter dated May 25. Apologizing for the “substantial delay” in responding, they said that school systems may legally consider race in admissions decisions — but in the case of TJ, they “did not find sufficient evidence that race was a factor in admissions” between 2000 and 2004, the period in question.

Cohen, a father of three Fairfax graduates — including two TJ alumni — filed an appeal in early June. So, now, federal authorities are faced with two civil rights complaints — each based on a different perspective on who is losing out in the battle to attend TJ and each a sign that the vaunted Fairfax school occupies a special role as a lightning rod for arguments about race, equity and opportunity.

“The community believes in the value of Thomas Jefferson,” said Ilryong Moon (At Large), chairman of the county School Board. “That is why a lot of people are taking an interest, rightfully so.”

Cohen’s complaint was distilled from a long article he wrote in 2003 for the Albany Law Review, in which he used statistical tools and other information to analyze TJ admissions decisions made in 2002.

That year, 11 black students made it into a pool of about 800 semifinalists based on the strength of their grades and scores on a math admissions test. Ten of them — including some who scored lower than white students who were rejected — were admitted after teacher recommendations and essays were considered.

According to Cohen’s analysis, black students were substantially more likely to be admitted than white students with similar credentials. Hispanic and Asian students also had an advantage over their white counterparts, he wrote, although a smaller one.

“The true purpose of the current admissions regime is to engage in invidious racial discrimination,” Cohen wrote.

His argument triggered a response from then-Superintendent Daniel Domenech, who called Cohen’s accusations “offensive and untrue,” and it touched off a firestorm at TJ and across Fairfax.

Cohen said he was working from a basic set of principles to which he still adheres.

“I have very simple values in this regard,” Cohen said in an interview Tuesday. “No government institution should discriminate against people based on race. They shouldn’t do it implicitly; they shouldn’t do it explicitly. They shouldn’t do it.”

In response to Cohen’s complaint, Education Department authorities analyzed five years of admissions data — from 2000 to 2004. Using a different set of statistical tools, they came to a different conclusion: There was no significant disparity between admission rates for black vs. white students.

The federal authorities also reviewed TJ admission policies and said they found no evidence that race was a factor, a claim that Cohen rejects.

In 2002, committees making admissions decisions were told in written guidelines that “standardized testing for minority students does not necessarily reflect their abilities” and that other factors, including teacher recommendations and essays, should be considered as indicators of success.

That reference to race was deleted in 2004 when the admissions process was overhauled. Since then, the population of black and Latino students has remained essentially unchanged and disproportionately low, triggering Monday’s complaint that the school system has systematically discriminated against those students.

That complaint, authored largely by former School Board member Tina Hone, alleges that the discrimination begins in elementary school through the underidentification of black and Latino kids for gifted-education programs.

Even as the population of those two minority groups has stayed stable, the proportion of white and Asian students has shifted dramatically.

Five years ago, white students made up 52 percent of the rising freshmen admitted to TJ, while Asian students accounted for 38 percent. By this year, those numbers had flipped: Of the ninth-graders entering TJ next year, 26 percent are white and 64 percent are Asian.

Meanwhile, Asians are only 19 percent of the county’s total student body.

Moon, the School Board chairman, said he hasn’t analyzed the reasons for the growing number of successful Asian applicants. But many of those students, he said, might have parents with backgrounds in math and science who encourage their kids to excel in those fields.

Moon said he doesn’t think that there is racial discrimination at work in TJ admissions. The board will weigh the concerns voiced by community members with advice from school system staff members as it moves forward with a decision on whether and how to tweak the admissions process, he said.

“I believe in the value of diversity,” he said. “If the student population does not reflect the diversity of the county, we certainly need to do a better job. At the same time, that doesn’t mean we’re going to diminish the rigor and the standards and the quality of students at TJ.”