A former F.B.I. informant accused of making false bribery claims about President Biden and his son Hunter — which were widely publicized by Republicans — claimed to have been fed information by Russian intelligence, according to a court filing on Tuesday.
In the memo, prosecutors portrayed the former informant, Alexander Smirnov, 43, as a serial liar incapable of telling the truth about even the most basic details of his own life. But Mr. Smirnov told federal investigators that “officials associated with Russian intelligence were involved in passing a story” about Hunter Biden.
Those disclosures, including Mr. Smirnov’s unverifiable claim that he met with Russian intelligence officials as recently as three months ago, made him a flight risk and endangered national security, Justice Department officials said. Mr. Smirnov had been held in custody in Las Vegas, where he has lived since 2022, since his arrest last week.
He was released from custody on Tuesday on a personal recognizance bond after a detention hearing, said his lawyers, David Chesnoff and Richard Schonfeld.
Prosecutors did not specify which story Russian intelligence is said to have been fed to Mr. Smirnov, an Israeli citizen. But they suggested they could not believe anything he said. And they had many tales to choose from.
The memo describes Mr. Smirnov as a human hall of mirrors: He fed the F.B.I. bogus information about the Bidens and misled prosecutors about his wealth, estimated at $6 million, while telling them he worked in the security business, even though the government could find no proof that was true.
“The misinformation he is spreading is not confined” to his false claims about the Bidens, wrote prosecutors working for David C. Weiss, the special counsel investigating Hunter Biden on tax and gun charges.
“He is actively peddling new lies that could impact U.S. elections after meeting with Russian intelligence officials in November,” they added.
That appeared to refer to Mr. Smirnov’s claim, made in late 2023 to the F.B.I., that he had spoken to the head of a Russian intelligence unit who said he had intercepted phone calls made by guests at a hotel overseas. Those included “several calls placed by prominent U.S. persons the Russian government may use as ‘kompromat’ in the 2024 election,” according to prosecutors.
Mr. Smirnov also told his F.B.I. handler that he was involved in meetings to help resolve the war in Ukraine, and that he had knowledge of assassination squads operating in “a third-party country.”
Last week, Mr. Weiss charged Mr. Smirnov with fabricating claims that President Biden and his son each sought $5 million bribes from a Ukrainian energy giant, Burisma, demanding the money to protect the company from an investigation by the country’s prosecutor general.
Those allegations, which prosecutors now say were brazen fabrications motivated by Mr. Smirnov’s animosity toward the president, were widely promoted by congressional Republicans who cited it as a justification for their now-stalled effort to impeach Mr. Biden.
Mr. Smirnov was taken into custody last week as he walked off an international flight from what prosecutors described as “a monthslong, multicountry foreign trip.” During that trip, he claimed to have had contacts with multiple foreign intelligence agencies and had planned to embark on a similar trip days later, according to the memo.
What makes the Smirnov case so unusual, aside from its political significance, is the willingness of the F.B.I. to publicly burn a confidential informant who had been on the bureau’s payroll as recently as last year. The filing contained excerpts from his source reporting documents, raw notes from interviews between handlers and informants that are considered some of the most sensitive federal law enforcement documents.
Also on Tuesday, Hunter Biden’s legal team filed motions in federal court arguing that the arrest of Mr. Smirnov — while unrelated to the charges Mr. Biden faces — has tainted the public’s perception of their client, making fair trials impossible.
“It now seems clear that the Smirnov allegations infected this case,” said Abbe Lowell, Mr. Biden’s lawyer, who accused Mr. Weiss of following “Mr. Smirnov down his rabbit hole of lies.”