George Santos Comes to Washington. It Could Be Awkward.

WASHINGTON — Representative-elect George Santos has been hard to pin down.

“No one can find him,” Representative Hakeem Jeffries, Democrat of New York and the incoming minority leader, said at a news conference last week, pressing for answers on the geyser of falsehoods about Mr. Santos’s background that have been revealed since he flipped a Democratic seat on Long Island in November.

But beginning on Tuesday, Mr. Santos will not be able to hide anymore.

He is to arrive on Capitol Hill for what is shaping up as a chaotic opening day of the 118th Congress, perhaps as the most notorious member of a new House Republican majority that is toiling to overcome deep divisions as it assumes control and the speakership is still up in the air.

It will most likely be an awkward moment for Mr. Santos, who will get his first taste of navigating the Capitol and its all-permeating press corps in the midst of a scandal of his own making.

He is under the shadow of active investigations by federal and local prosecutors into potential criminal activity during his two congressional campaigns. Prosecutors told The New York Times on Monday that Brazilian law enforcement authorities intended to revive fraud charges against him stemming from an incident in 2008 regarding a stolen checkbook.

Democrats are already calling for him to give up his seat, and members of his own party are demanding more detailed explanations of his conduct.

That includes making up claims about his résumé, his education, his ties to Wall Street firms and his charitable endeavors — all of which have been revealed as part of a fantasy persona created as the backbone of his pitch to voters.

In addition to his background, Mr. Santos has misrepresented parts of his finances and filed incomplete or inaccurate congressional disclosures. He has also claimed that he is Jewish and the descendant of Holocaust survivors. Mr. Santos is Catholic.

Federal and local prosecutors are investigating whether he committed crimes involving his finances or misleading statements.

Mr. Santos, the first openly gay Republican to win a House seat as a non-incumbent, has yet to offer a full accounting to the voters who elected him based on a largely made-up biography. He has admitted to “embellishing” his résumé and to the fact that he did not graduate from any institution of higher education.

He has promised to tell his whole story at some point.

Still, it remains unclear what, if anything, Republicans will do to punish him, or how he will choose to comport himself once he is sworn in on Tuesday. Representative Kevin McCarthy, Republican of California and the minority leader, cannot afford to lose a single vote as he labors to win the speakership. He has remained silent about Mr. Santos and his position in the Republican conference.

Mr. McCarthy, for now, has more pressing concerns, like his own political future, to contend with.

And for now, Mr. Santos appears ready to keep moving forward.

“It was an honor to tour the United States Merchant Marine Academy in Kings Point today,” he tweeted three days after Christmas, with a photograph of him and a large ship’s wheel. “In Congress, I look forward to working alongside them to fully utilize this amazing resource we have in our own backyard.”