LAS VEGAS — The former FBI informant who allegedly fed the bureau false information about President Joe Biden and his son Hunter Biden during the 2020 presidential campaign is set to appear at a detention hearing in a federal courtroom in Las Vegas on Tuesday.

Alexander Smirnov, a 43-year-old who had been working as a confidential human source for the FBI since 2010, said that “officials associated with Russian intelligence” were involved in passing along a story about Hunter Biden, prosecutors said in a filing Tuesday, alleging that Smirnov “is actively peddling new lies that could impact U.S. elections after meeting with Russian intelligence officials in November.”

Smirnov was arrested last week in Las Vegas after returning on an international flight and is facing two counts in connection with lies he allegedly told his FBI handler. His defense attorneys say he is an American citizen who also holds an Israeli passport. His detention hearing is set to begin at 3 p.m. local time.

Smirnov, according to prosecutors with special counsel David Weiss’ office, “provided false derogatory information to the FBI” about the Bidens, including the false allegation that officials with Burisma, a Ukrainian energy company that employed Hunter Biden, had paid the Bidens $5 million each and that it would take investigators 10 years to find the fake payments.

Smirnov’s claims were a key part of the Republican impeachment inquiry into Joe Biden, with GOP leaders citing the unverified claims of the FBI confidential human source over and over again. Rep. Jim Jordan, R-Ohio, the Judiciary Committee chairman helping to lead the GOP’s impeachment push, said just weeks ago that the now-debunked claims from Smirnov were the “most corroborating evidence” that Republicans had in their ongoing impeachment inquiry.

House Republicans have spent the days since the indictment downplaying the impact it had on their impeachment inquiry, with House Oversight Committee Chairman James Comer, R-Ky., saying their case “is not reliant” on the false claims. Comer had threatened to hold the FBI director in contempt over the summer, ultimately convincing the bureau to show members of the Oversight Committee an “FD-1023 form” that documented the false statements Smirnov allegedly made to his FBI handler in 2020, though the bureau emphasized at the time that the existence of the form did not mean the claims were vetted. One of the Republicans who viewed the form quickly proclaimed that Joe Biden was “100% guilty” of bribery.

Smirnov’s attorneys, David Z. Chesnoff and Richard A. Schonfeld, said in a statement they were “pleased to be representing Mr. Smirnov” and that their client “is presumed innocent and needs to be released from custody so he can effectively fight the power of the government.”

In a detention memo, prosecutors said that Smirnov has “extensive foreign ties, including, most troublingly and by his own account, contact with foreign intelligence services, including Russian intelligence agencies, and has had such contacts recently.”

In a court filing on Tuesday that grew out of Hunter Biden’s criminal case in Delaware, Hunter Biden’s attorneys wrote that it “should have been obvious to everyone” that Smirnov was lying, noting that the investigation based on the lies was closed in August 2020, when then-President Donald Trump’s appointees headed the Justice Department.

In a court filing Tuesday, Hunter Biden’s attorneys questioned why Weiss’s office spent months last year reinvestigating Smirnov’s claims.

“The Special Counsel charged Mr. Smirnov with lying and obstruction, but the more interesting part of this story is not that Mr. Smirnov lied,” Hunter Biden’s attorneys wrote. “It is more remarkable that beginning in July 2023, the Special Counsel’s team would follow Mr. Smirnov down his rabbit hole of lies as long as it did.”

Fitzpatrick reported from Las Vegas. Reilly reported from Washington.