A top Republican senator is expressing concern after sources confirmed to Fox News President Obama is planning to nominate James Comey, a former Justice Department official under President George W. Bush, to be the next director of the FBI.
Comey, a Republican, would replace current director Robert Mueller, who has led the agency since 2001. His term expires in September.
Iowa Sen. Charles Grassley, the top Republican on the Senate Judiciary Committee, said he had not heard from the White House about Comey's nomination, but that he was concerned about Comey's connections to a Connecticut-based hedge fund Bridgewater Associates.
Comey served as general counsel for the hedge fund from 2010 until earlier this year, when he left and became a lecturer and researcher at Columbia Law School.
"If he's nominated, he would have to answer questions about his recent work in the hedge fund industry," Grassley said. "The administration's efforts to criminally prosecute Wall Street for its part in the economic downturn have been abysmal, and his agency would have to help build the case against some of his colleagues."
It was unclear when the nomination would be officially announced, but the White House was expected to move quickly since Comey must be confirmed by the Senate and Congress will be out of town in August.
Comey was deputy attorney general in 2005 when he unsuccessfully tried to limit tough interrogation tactics against suspected terrorists. He told then-Attorney General Alberto Gonzales that some of the practices were wrong and would damage the department's reputation.
Some Democrats denounced those methods as torture, particularly the use of waterboarding, which produces the same sensation as drowning.
Comey became a hero to Democratic opponents of Bush's warrantless wiretapping program when Comey refused for a time to reauthorize it. Bush revised the surveillance program when confronted with the threat of resignation by Comey and Mueller.
Earlier in his career, Comey served as U.S. attorney for the Southern District of New York, one of the nation's most prominent prosecutorial offices and one at the front lines of terrorism, corporate malfeasance, organized crime and the war on drugs.
As an assistant U.S. attorney in Virginia, Comey handled the investigation of the 1996 bombing of the Khobar Towers housing complex near Dhahran, Saudi Arabia, that killed 19 U.S. military personnel.
Comey led the Justice Department's corporate fraud task force and spurred the creation of violent crime impact teams in 20 cities, focusing on crimes committed with guns.
Comey also was at the center of one of the Bush administration's great controversies -- an episode that focused attention on the administration's controversial tactics in the war on terror.
In stunning testimony to the Senate Judiciary Committee in 2007, Comey said he thought Bush's no-warrant wiretapping program was so questionable that Comey refused for a time to reauthorize it, leading to a standoff with White House officials at the bedside of ailing Attorney General John Ashcroft.
Comey said he refused to re-certify the program because Ashcroft had reservations about its legality.
Senior government officials had expressed concerns about whether the National Security Agency, which administered the warrantless eavesdropping program, had the proper oversight in place. Other concerns included whether any president possessed the legal and constitutional authority to authorize the program as it was carried out at the time.
The White House, Comey said, recertified the program without the Justice Department's signoff, allowing it to operate for about three weeks without concurrence on whether it was legal. Comey, Ashcroft, Mueller and other Justice Department officials at one point considered resigning, Comey said.
"I couldn't stay if the administration was going to engage in conduct that the Department of Justice had said had no legal basis," Comey told the Senate panel.
A day after the March 10, 2004, incident at Ashcroft's hospital bedside, Bush ordered changes to the program to accommodate the department's concerns. Ashcroft signed the presidential order to recertify the program about three weeks later.
The dramatic hospital confrontation involved Comey, who was the acting attorney general during Ashcroft's absence, and a White House team that included Bush's then-counsel, Alberto Gonzales, and White House chief of staff Andy Card, Comey said. Gonzales later succeeded Ashcroft as attorney general.
Comey testified that when he refused to certify the program, Gonzales and Card headed to Ashcroft's sick bed in the intensive care unit at George Washington University Hospital.
When Gonzales appealed to Ashcroft, the ailing attorney general lifted his head off the pillow and in straightforward terms described his views of the program, Comey said. Then he pointed out that Comey, not Ashcroft, held the powers of the attorney general at that moment.
Gonzales and Card then left the hospital room, Comey said.
"I was angry," Comey told the panel. "I thought I had just witnessed an effort to take advantage of a very sick man who did not have the powers of the attorney general."
The change in leadership comes as the FBI and Justice Department are under scrutiny for their handing of several investigations. Obama has ordered a review of FBI investigations into leaks to reporters, including the secret gathering of Associated Press phone records and emails of a Fox News reporter.
Additionally, there have been questions raised about whether the FBI properly responded to warnings from Russian authorities about a suspect in the Boston Marathon bombings.
The agency, meanwhile, is conducting a highly-anticipated investigation into the Internal Revenue Service over its handling of conservative groups seeking tax exempt status.
Comey reportedly edged out Lisa Monaco, a top National Security Council official, for the job.
The Associated Press contributed to this report