by Matt Zapotosky

President Trump announced Wednesday that he would nominate Christopher A. Wray — a white-collar criminal defense attorney who led the Justice Department's criminal division during the George W. Bush administration — to serve as the next FBI director.

Trump posted the announcement on Twitter, declaring Wray a "man of impeccable credentials." His appointment would still have to be confirmed by the Senate, which is sure to scrutinize Trump's nominee intensely.

Wray, now a partner at King & Spalding, led the criminal division from 2003 to 2005, and his firm biography says that he "helped lead the Department's efforts to address the wave of corporate fraud scandals and restore integrity to U.S. financial markets." He oversaw the president's corporate fraud task force and oversaw the Enron Task Force. Before that, he worked in a variety of other Justice Department roles, including as a federal prosecutor in Atlanta.

More recently, he has served as attorney for New Jersey Gov. Chris Christie (R), a Trump ally. He also represented the Swiss bank Credit Suisse AG in a tax evasion case that ended in a $2.6 billion settlement with U.S. authorities. In 2014, the bank pleaded guilty to conspiring to aid and assist U.S. taxpayers in filing false income tax returns.

In a statement, Wray called his selection a "great honor" and said, "I look forward to serving the American people with integrity as the leader of what I know firsthand to be an extraordinary group of men and women who have dedicated their careers to protecting this country."

Trump said Wray would "again serve his country as a fierce guardian of the law and model of integrity once the Senate confirms him to lead the FBI."

It is unclear how soon that could happen. Sen. Charles E. Grassley (R-Iowa), who chairs the Judiciary Committee, said the panel would begin consideration of his nomination once receiving it formally, which he indicated might take a few weeks.

People who had worked with Wray said he is an accomplished, low-key lawyer who would not hesitate to stand up to the president if necessary.

Bill Mateja, who worked with Wray in the Justice Department in the early 2000s and is now in private practice at the Polsinelli law firm, said, "If people thought that Trump might pick a lackey, Chris Wray is not Trump's lackey."

But others were not so sure.

Faiz Shakir, national political director of the American Civil Liberties Union, said in a statement that Wray's firm's legal work for the Trump family and his history of defending Christie, who was Trump's transition director, "makes us question his ability to lead the FBI with the independence, evenhanded judgment, and commitment to the rule of law that the agency deserves."

Wray represented Christie during the federal investigation into politically motivated lane closures at the George Washington Bridge that connects New Jersey and Manhattan. He kept a low profile during the scandal, but behind the scenes, he served as a comforting presence to Christie, who on Wednesday called Wray an "extraordinary lawyer" and "a nonpolitical choice."

"When I was at the absolute lowest point of my professional life, he's who I called," Christie told reporters at an event in New Jersey. "I don't think you can get a better recommendation than that."

Christie would not say whether he recommended Wray to Trump.

Wray's nomination will bring an end to a herky-jerky search that has seen several contenders take their own names out of the running. Top Justice Department officials initially held talks with eight candidates, and Trump said he could make a "fast decision" on whom to select because "almost all of them are very well known."

None of those people ultimately panned out, and Trump soon turned his focus to former senator and Democratic vice presidential nominee Joe Lieberman. But Lieberman, too, withdrew from consideration because another lawyer at his firm was tapped to help Trump with the investigation into whether his campaign coordinated with Russia during the 2016 election.

Legislators vowed to scrutinize Wray — although he did not face immediate condemnation from Democrats. Rep. John Conyers Jr. (D-Mich.) said he was "deeply concerned that the next director is being selected according to the criteria of a president, whose campaign and administration are under investigation, and who fired the prior FBI director on the basis of his zeal in investigating these matters and refusal to swear loyalty to the president" but that he looked forward to learning more about Wray.

Sen. Christopher A. Coons (D-Del.), who serves on the Judiciary Committee, said, "I'm encouraged that President Trump has nominated someone with significant federal law enforcement experience, rather than a career in partisan politics, as was rumored over the past several weeks."

Lawmakers will probably examine whether Wray's work presents any conflicts of interest. Bobby Burchfield, another lawyer at Wray's firm, was hired earlier this year by Trump's company as an ethics adviser — though there was no indication Wray himself did work for Trump or his businesses. Wray's firm also indicates on its website that it did work for at least one unnamed major Russian oil company.

If confirmed, Wray will succeed James B. Comey, whom Trump abruptly fired last month amid the Russia investigation. That probe is now being overseen by a special counsel, former FBI director Robert S. Mueller III. Andrew McCabe, who had been deputy director, is leading the FBI on an interim basis.

Trump's announcement on Wray — which took Grassley and Sen. Dianne Feinstein (Calif.), the ranking Democrat of the Judiciary Committee, by surprise — came the day before Comey is scheduled to testify before the Senate Intelligence Committee in what will probably be one of the most closely watched congressional hearings in recent years. Comey has alleged that, before Trump fired him, the president requested that his FBI director pledge loyalty and urged him to back off his investigation into former national security adviser Michael Flynn.

The firing itself was an unusual move. FBI directors are generally appointed to 10-year terms so they can avoid political interference, and Trump has declared he was thinking of the Russia probe when he ousted Comey.

Joe Robuck, a retired FBI special agent who worked with Wray when Wray was a federal prosecutor in Atlanta and has remained in contact with him through the years, said he first saw the news that his friend had been interviewed last week and sent him an email saying, "Chris, you got to go for it. The country needs you."

Robuck said Wray later called to ask what current FBI agents might think of him taking the post, having not worked himself in the bureau previously.

Robuck said Wray did not bring up the president, but he did mention an interview with Attorney General Jeff Sessions.

Sessions, Robuck said, had asked Wray about his experience as an assistant U.S. attorney, and Wray told him about a case he and Robuck had worked together years ago in which an Atlanta investment officer illegally steered millions of dollars to a particular banker in exchange for payoffs. Robuck said he had talked to jurors after the trial in that case, and they told him they had a nickname for Wray: "the bulldog."

"He's completely mission-oriented," Robuck said. "It's a tough job, it's a really hard job, but he will deal with the pressure, and he won't let anybody influence him."

Ellen Nakashima, Devlin Barrett, Ed O'Keefe, Karoun Demirjian, Shawn Boburg, Julie Tate and Sari Horwitz contributed to this report.