Washington - The F.B.I. has failed to aggressively investigate accusations of espionage against a translator at the bureau and fired the translator's co-worker in large part for bringing the accusations, the Justice Department's inspector general concluded on Friday.

In a long-awaited report that the Justice Department sought for months to keep classified, the inspector general issued a sharp rebuke to the F.B.I. over its handling of claims of espionage and ineptitude made by Sibel Edmonds, a bureau translator who was fired in 2002 after superiors deemed her conduct "disruptive."

Ms. Edmonds, who translated material in Turkish, Persian and Azerbaijani, had complained about slipshod translations and management problems in the bureau's translation section and raised accusations of possible espionage against a fellow linguist.

The report from the office of Glenn A. Fine, the Justice Department's inspector general, reached no conclusions about whether Ms. Edmonds's co-worker had actually engaged in espionage, and it did not give details about the espionage accusations because they remain classified. But officials have said Ms. Edmonds said the co-worker, a fellow Turkish linguist, had blocked the translation of material involving foreign acquaintances of hers who had come under suspicion.

In general, Mr. Fine's investigation found that many of Ms. Edmonds's accusations "were supported, that the F.B.I. did not take them seriously enough and that her allegations were, in fact, the most significant factor in the F.B.I.'s decision to terminate her services."

Ms. Edmonds's case has become a cause célèbre for critics who accused the bureau of retaliating against her and other whistle-blowers who have sought to expose management problems related to the campaign against terrorism.

The American Civil Liberties Union joined her cause earlier this week, asking an appellate court to reinstate a whistle-blower lawsuit she brought against the government. The suit was dismissed last year after Attorney General John Ashcroft, invoking a rarely used power, declared her case to be a matter of "state secret" privilege, and the Justice Department retroactively classified a 2002 Congressional briefing about it.

Responding to the investigation's calls for improvements in the management of translation services, the F.B.I. said Friday that it had taken steps to reorganize the operation and instituted "competency models" for hiring and training translators. A broader review by the inspector general released in September had found systematic problems in the F.B.I.'s translation capabilities and large backlogs in its translation of terrorism-related material.

The F.B.I. also said Friday that it was continuing to investigate Ms. Edmonds's claims and restated its commitment to ensuring that whistle-blowers "who raise good faith concerns" do not face retaliation.

Ms. Edmonds, for her part, said she viewed the inspector general's report as "an absolute vindication."

After all the delays in getting this story out, I wasn't expecting a lot," she said in an interview. "This report is certainly more than I expected, and I'm actually pretty pleased."

Senators Patrick J. Leahy of Vermont, a Democrat, and Charles E. Grassley of Iowa, a Republican, who have been two of the F.B.I.'s toughest critics, said the report underscored their broader concerns about the bureau's treatment of dissenters, particularly on critical matters involving terrorism and espionage.

"This report confirms that the F.B.I. failed to treat this case as seriously as the situation demanded," Mr. Leahy said. "It is unacceptable, and it deeply concerns us, that in the wake of the Robert Hanssen spy case, and in the months following Sept. 11, the F.B.I. failed to vigorously investigate these grave allegations."