WASHINGTON – The Justice Department said today it is investigating whether Attorney General Gonzales lied or otherwise misled Congress last month in sworn testimony about the Bush administration’s domestic terrorist spying program.

Details of the inquiry by Justice Department Inspector General Glenn Fine were released three days after Mr. Gonzales abruptly announced he was stepping down despite months of vowing to remain on the job.

In a letter to Senate Judiciary Chairman Leahy, who two weeks ago asked for the inquiry, Mr. Fine said his investigators believe they “will be able to assess most of the issues that you raise in your letter.”

Mr. Leahy had asked Mr. Fine to look into whether Mr. Gonzales gave inaccurate testimony about the firings of several U.S. attorneys last year.

“You identified five issues and asked that we investigate whether the statements made by the attorney general were intentionally false, misleading, or inappropriate,” Mr. Fine wrote in his four-paragraph response to Mr. Leahy in the letter dated today.

“The OIG has ongoing investigations that relate to most of the subjects addressed by the attorney general’s testimony that you identified,” Mr. Fine told Mr. Leahy.

Spokesmen for Mr. Gonzales had no immediate comment.

Senate and House lawmakers have said they will continue congressional investigations of Mr. Gonzales’ leadership and management at the Justice Department, despite the attorney general’s announcement Monday that he has resigned, effective September 17.

Mr. Gonzales’ resignation left the White House scrambling to find a replacement. So far, no single candidate has emerged from a list of more than two dozen lawyers, judges, GOP politicians, and current and former Justice Department officials being discussed.

A White House spokeswoman, Dana Perino, said today it was unlikely that Mr. Gonzales’ successor will be named until President Bush returns September 9 from the annual Asia-Pacific Economic Cooperation forum in Australia.

“We would expect to do it shortly after returning from APEC,” Ms. Perino said. “This is something we want to do in an expeditious manner.”

She would not discuss any potential candidates.

Mr. Gonzales announced his departure a month after his truthfulness was challenged during a Senate Judiciary Committee hearing. At the bitter hearing, Mr. Gonzales denied that he tried in 2004, as White House counsel, to push the Justice Department into approving the administration’s Terrorist Surveillance Program – despite concerns that it was illegal.

Mr. Gonzales said the March 2004 dispute – which played out in part at the hospital bedside of a groggy Attorney General Ashcroft – focused on “other intelligence activities.” Mr. Ashcroft was recovering from surgery at the time. Mr. Gonzales succeeded him in 2005.

Mr. Gonzales’ testimony to Congress was contradicted two days later by FBI Director Robert Mueller, who said the dispute was about the program that then allowed the National Security Agency to eavesdrop on domestic terror suspects without court review.

Mr. Leahy, in a statement, said the internal probe “can help restore independence and accountability, which have been sorely lacking at the Justice Department.”

“These actions have eroded the public’s trust and undermined morale within our justice system, from the top ranks to the cop on the beat,” Mr. Leahy said. “The current attorney general is leaving, but these questions remain.”

Mr. Fine and counsel to the department’s Office of Professional Responsibility, H. Marshall Jarrett, launched a joint internal Justice review last March into whether the prosecutor firings were politically motivated. The inquiry was later expanded to include whether Mr. Gonzales inappropriately discussed the ousters in a meeting that a former aide, Monica Goodling, later said made her feel “uncomfortable.”

Investigators also are looking into allegations that Ms. Goodling, and possibly other aides, let politics play a part in hiring career prosecutors – a violation of federal law.

The investigation is not expected to be finished for several more months, and possibly not until early 2008.

Mr. Fine’s office already is investigating the Justice Department’s role and use of information gathered as part of the domestic spying program. A follow-up audit, expected by late December, is being conducted into on whether the FBI has taken steps to end its mishandling of administrative subpoenas – known as national security letters – that allowed agents to improperly obtain personal information about people in America.

Mr. Leahy also asked Mr. Fine, in his August 16 request, to look into whether Mr. Gonzales was not telling the truth when he testified in 2005 that there “has not been one verified case of civil liberties abuse” involving the NSLs.

“It is appropriate that the Inspector General will examine whether the Attorney General was honest with this and other congressional committees about these crucial issues,” Mr. Leahy wrote.