The flashpoint in the tensions between Mr. Greenfeld and his political supervisors came four months ago, when statisticians at the agency were preparing to announce the results of a major study on traffic stops and racial profiling, which found disparities in how racial groups were treated once they were stopped by the police.

Political supervisors within the Office of Justice Programs ordered Mr. Greenfeld to delete certain references to the disparities from a news release that was drafted to announce the findings, according to more than a half-dozen Justice Department officials with knowledge of the situation. The officials, most of whom said they were supporters of Mr. Greenfeld, spoke on condition of anonymity because they were not authorized to discuss personnel matters.

Mr. Greenfeld refused to delete the racial references, arguing to his supervisors that the omissions would make the public announcement incomplete and misleading. Instead, the Justice Department opted not to issue a news release on the findings and posted the report online.

Some statisticians said that decision all but assured the report would get lost amid the avalanche of studies issued by the government. A computer search of news articles found no mentions of the study.

Congressional opponents of racial profiling, who have criticized what they see as an ambivalent stance on the issue by the Bush administration, said they were frustrated to learn that the Justice Department had completed the Congressionally mandated study without announcing its findings or briefing members of Congress on it. They accused the Justice Department of effectively burying the findings to play down new data that would add grist to the debate over using racial and ethnic data in law enforcement and terrorism investigations.