WASHINGTON -- The Obama administration has begun to search for a replacement for FBI director Robert Mueller, and for the first time one of the leading contenders is a woman.
One of several people under consideration, according to current and past administration officials, is Lisa Monaco, who left a senior post at the Justice Department this month to become President Barack Obama's top counterterrorism adviser.
Mr. Mueller, 68, will step down Sept. 4 after 12 years on the job. Since taking the helm a week before the Sept. 11, 2001, attacks, he has overseen the bureau's transformation into a worldwide counterterrorism operation.
The director's job is limited to 10 years by law, but the Senate in 2011 extended Mr. Mueller's term for two years at the request of Mr. Obama after a search for a replacement failed.
Officials said the administration wants to find a successor soon so that person can be vetted, nominated and confirmed before Congress goes on summer recess. In the early stages, the process is being coordinated by the Justice Department.
"Mueller will leave very big shoes to fill," said one Justice Department official, who spoke on the condition of anonymity because he was not authorized to speak to the media. "Two years ago, he was portrayed as the indispensable man. Now, the FBI is going to have to do without the indispensable man in a matter of a few months."
Among the names that have surfaced as contenders are Ms. Monaco, who oversaw the National Security Division at Justice before moving to the White House; Merrick Garland, chief judge of the U.S. Court of Appeals for the D.C. Circuit; James Comey, deputy attorney general in the George W. Bush administration; Neil MacBride, U.S. attorney for the Eastern District of Virginia; and Patrick Fitzgerald, former U.S. attorney in Chicago.
Spokeswomen for the White House and the Justice Department declined to comment on the search. Other current officials described the process on condition that they not be identified when talking about internal deliberations.
"The problem we quickly ran into two years ago is that there just aren't a lot of people who have Bob Mueller's stature, but eventually you have to face the fact that he can't stay in the job forever," said Matthew Miller, a former Justice spokesman. "No one can fill his shoes on day one, but we're four years into the administration now, and there are a number of talented people who have added some significant experience to their resumes."
The next FBI director will lead an agency with a more complex and demanding mission than the agency Mr. Mueller took before the Sept. 11 attacks. Since then, he has led the bureau's evolution from traditional crime fighting to a heavy focus on preventing terrorist attacks.
While Mr. Mueller has won bipartisan support through two administrations, the bureau has increased its surveillance operations in ways that critics say sometimes violate civil liberties.
Law enforcement experts said the new director will need to be experienced in both law enforcement and management, given the vast expansion of the FBI's operations over the past decade.
Ms. Monaco, 44, would be the first woman to lead the FBI. Before heading the National Security Division at Justice, she was a counsel to then-Attorney General Janet Reno, an assistant U.S. attorney for the District of Columbia and Mr. Mueller's chief of staff at the FBI.
One concern about Ms. Monaco mentioned by department insiders is that she just became Mr. Obama's chief counterterrorism adviser, replacing John Brennan when he became CIA director.
"The president is going to be personally relying on her to fulfill that role," said one Justice official. "They might not be open to having a revolving door in that critical position at the White House."
But another administration official said Ms. Monaco's move to the White House might work in her favor because the president can closely observe her leadership skills.
Other contenders have pluses and minuses. Judge Garland and Mr. Comey, both of whom were considered two years ago, are highly respected and experienced, but there are questions about whether either would want the job.
Mr. Fitzgerald, regarded as an independent-minded prosecutor, might face a tough confirmation because he prosecuted and convicted Lewis "Scooter" Libby, then-Vice President Dick Cheney's top aide, in the Valerie Plame leak case. Mr. MacBride has established a strong track record for prosecuting national security cases, a mainstay of the bureau's operations.