By Steve Holland
WASHINGTON (Reuters) - President Barack Obama is expected to nominate former Justice Department official James Comey as his next head of the FBI, a source said on Wednesday.
If confirmed by the Senate, Comey, a Republican, would replace FBI Director Robert Mueller, who has led the agency since just before the September 11, 2001, attacks. Mueller is expected to step down this fall.
The White House would not comment on Obama's decision but the source said Obama had been leaning toward Comey in recent days. It was unclear when an announcement would be made.
White House homeland security adviser Lisa Monaco, who emerged as an instrumental aide to Obama during the Boston Marathon bombings last month, also had been under consideration.
Comey, 52, served as deputy U.S. attorney general for President George W. Bush. He had previously been the U.S. attorney for the Southern District of New York.
In an earlier post as assistant U.S. attorney for the Eastern District of Virginia, Comey handled the Khobar Towers bombing case that arose out of an attack on a U.S. military facility in Saudi Arabia in 1996. Seventeen U.S. military members died in the attack.
Comey gained notoriety for refusing in 2004 to certify the legal aspects of National Security Agency domestic surveillance during a stint as acting attorney general while John Ashcroft was hospitalized with pancreatitis.
That refusal prompted senior White House officials, counsel Alberto Gonzales and chief of staff Andrew Card, to try to persuade Ashcroft to sign the certification. Comey, who was in the room, said Ashcroft refused.
Comey later told the Senate Judiciary Committee at a 2007 hearing that the situation was "probably the most difficult night of my professional life." His actions endeared him to many Democrats opposed to the Bush's domestic surveillance program.
After leaving the Justice Department in 2005, Comey was general counsel to aerospace giant Lockheed Martin until 2010.
Comey most recently joined Columbia University's law school as a senior research scholar after working for Bridgewater Associates, an investment fund, from 2010 to 2013. He was general counsel for aerospace giant Lockheed Martin from 2005 to 2010.
(Additional reporting by Mark Felsenthal and David Ingram; Editing by Stacey Joyce and Bill Trott)