Reporting by CBS News' Paula Reid, Jeff Pegues and Fin Gomez

The White House has authorized the FBI to expand its supplemental background investigation to include interviews of anyone it deems necessary to vet claims of sexual misconduct against Supreme Court nominee Brett Kavanaugh, a Justice Department official and an administration official briefed on the development confirm to CBS News.

President Trump has deferred to the Senate Judiciary Committee during Kavanaugh's confirmation process — particularly regarding the allegations of sexual misconduct. Last week, Capitol Hill and the nation were riveted by testimony from Kavanaugh and Christine Blasey Ford, who accuses Kavanaugh of assaulting her when they were both in high school. Kavanaugh insisted on his innocence, while Ford insisted she is "100 percent" sure it was Kavanaugh who allegedly assaulted her.

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The week-long timeline for the review still applies, those sources say. The New York Times first reported the White House had authorized the expanded review. The FBI is expected to meet the Friday deadline, according to a former top FBI official, who is familiar with the process.

CBS News confirms that the key witness, according to Ford's congressional testimony, Kavanaugh friend Mark Judge, has been interviewed by the FBI.

An attorney who represents Leland Keyser, who Ford said was at the house that night, told CBS News Keyser met with the FBI on Saturday. Through the attorney, Howard Walsh, Keyser has said she does not refute Ford's account but that she has no recollection of ever being at a party or gathering where Kavanaugh was present, with or without Ford.

There is a war-room atmosphere around the case, the former FBI official says. In the course of the supplemental background check, agents will be talking with those who have made the core allegations, and then they will try to corroborate the information. One example -- Ford told the Senate Judiciary Committee that she saw Judge at a Safeway where he was working "six to eight weeks" after the alleged assault. Judge has said in his memoir, "Wasted: Tales of a Gen X Drunk," that "to raise money for football camp, I spent a few weeks working as a bag boy at the local supermarket." The FBI will be trying to locate the records from Safeway where Mark Judge worked.

The FBI likely faces its share of challenges in this process because of the timing of the revelation of Ford's allegation so late in the confirmation process. The headlines the case has generated might cloud and confuse the memory of some of the key players.

Because this is an inquiry and not a criminal investigation, the FBI will not compel anyone to talk to them. Witnesses do not have to cooperate. However, if a witness does cooperate, the individual can be charged with making false statements to the FBI if he or she lies.

At the end of the process, the bureau's report will include a summary of the interviews and anything done to corroborate the statements made, but there will be no conclusions.

President Trump, who said he ordered the supplemental investigation upon request from the Senate Judiciary Committee last week, suggested during a press conference in the White House Rose Garden Monday that he wants a "very comprehensive" probe, and the FBI should interview "anybody" they want to, "within reason." Asked if he would instruct White House counsel Don McGahn to tell allow the FBI to interview anyone it deems necessary, Mr. Trump claimed he already has.

"Well, I have so instructed him and I did it again over the weekend because I see the press was - I don't want to use the word in this case, misleading - it's much more complex subject than anybody would understand and then most people understand," the president said.

When the FBI's time to complete the investigation expires on Friday, Senate Majority Leader Mitch McConnell plans to put his confirmation to a vote by the Senate. "The time for endless delay and obstruction has come to a close," McConnell said on the Senate floor Monday. "Judge Kavanaugh's nomination is out of committee. We're considering it here on the floor." He added, "We'll be voting this week."

Kathryn Watson and Arden Farhi contributed to this report.