Who will be the next director of the FBI?

With the clock ticking down on his term, FBI Director Robert Mueller made one of his last appearances before Congress on Wednesday, with much of the standard verbal combat replaced by accolades from Republicans and Democrats on the House Judiciary Committee. While the good-byes are just starting, the search for Mueller's successor has been well underway for months.

The search is being led by Vice President Joseph Biden and Louis Freeh, the FBI Director for almost eight years before Mueller took the reins on September 4, 2001, just one week before the September 11th attacks.

Mueller, 66, is the longest serving FBI director since Congress created the ten-year term in 1976. Over ten grueling years, he's captained a wholesale reorganization of the bureau -- more than half of its current workforce was hired after 9/11. He told the committee that the transformation is still underway and that there is no let-up in the terrorist threat.

The administration has cast a wide net for candidates to run what's become "Mueller's FBI," combing the ranks of high-level prosecutors, administrators, agents, judges and police chiefs. While the search itself is being conducted in secret, insiders have been handicapping a short list which includes:

Patrick Fitzgerald -- the U.S. Attorney in Chicago: He is known as being fiercely independent and ferociously dogged. While Fitzgerald is best known for the successful prosecution of former Vice President Dick Cheney's top aide, I. Lewis "Scooter" Libby and the ongoing case against former Illinois Gov. Rod Blagojevich, his terrorism knowledge runs deep and goes back to investigations of Osama bin Laden in 1996.

John Pistole -- the head of the Transportation Security Administration: Pistole was chosen by this White House for the post and won Senate confirmation. Pistole received a comedic shout-out during the Gridiron Dinner when President Obama told the crowd: "America's favorite voyeur, TSA Administrator John Pistole is in the house. No hard feelings, John. I mean that literally."

Michael Mason - a former senior official at the FBI and one of its most popular: Mason is now a top security official with Verizon Communications, Inc. If chosen, Mason would be the first African-American FBI Director.

James Comey -- Former Deputy Attorney General and U.S. Attorney in the Southern District of New York: In one of the most memorable chapters of the Bush administration's internal power struggles, Comey led a group of senior officials, including Mueller, who threatened to resign over the administration's electronic eavesdropping program.

Mary Jo White -- another highly regarded former US Attorney in the Southern District of New York (almost 9 years), and current partner in the New York law firm, Debevoise & Plimpton: If selected, White would be the first woman FBI Director.

Kenneth Wainstein - a protege of Mueller and the first chief of the Justice Department's National Security Division, created in the post 9/11 reorganization: Wainstein was White House Homeland Security Advisor to former President George Bush and a longtime federal prosecutor.

Raymond Kelly - New York City Police Commissioner (not once but twice, with his first appointment occurring during the 1993 World Trade Center bombing): Kelly, with two law degrees, commands his own anti-terrorism and intelligence operation in New York. As a Treasury Undersecretary in 1996, he oversaw the ATF, the Secret Service and Customs.

William Bratton - another of the "super chiefs," who led both the NYPD and the Los Angeles Police Departments: Bratton is credited with innovative programs that brought down serious crime in both cities; now Chairman of Kroll, the international investigative services company.

The administration has had the luxury of time in vetting its candidates given that Mueller's term will end five months from now, precisely on September 4th. While the White House has not announced its timetable, several people tracking the sweepstakes expect a nominee in late April or early May.