The FBI informant charged with telling lies about President Biden and his son Hunter was rearrested Thursday in Las Vegas, apparently out of concern he might flee — just days after a federal magistrate decided he could be released on bond.

Alexander Smirnov, whose arrest last week surprised Republican and Democratic lawmakers alike, was taken into custody again Thursday morning in his lawyer’s office. Prosecutors had argued that Smirnov’s claims of having significant relationships with Russian intelligence operatives, as well as millions of dollars at his disposal, meant that he was a flight risk.

“He was inside our law office at the time of his arrest, preparing his defense,� Smirnov’s attorneys, David Z. Chesnoff and Richard A. Schonfeld, said in a statement.

In a court filing, the defense lawyers called their client’s rearrest “bizarre� and unnecessary and ask that he be released again. “At no time since his release on February 20, 2024 has Mr. Smirnov left Clark County, Nevada,� the lawyers wrote, adding that the fact he was arrested in their own office shows he was not preparing to flee.

Smirnov was indicted by a Los Angeles grand jury in a case brought by special counsel David Weiss, who is overseeing a separate investigation and prosecution of Hunter Biden for gun and tax charges. A dual U.S.-Israeli citizen, Smirnov is charged with lying to the FBI in 2020 when he claimed to have knowledge of corruption by Joe Biden and his son.

The accusations by Smirnov against the Bidens, memorialized in an FBI document, were championed by congressional Republicans last year as a central part of their effort to impeach President Biden and accuse his family of corruption related to the Ukrainian firm Burisma. Smirnov’s indictment and detention memo, however, suggest the allegations were not only false, but possibly a Russian-inspired smear.

“During his custodial interview on February 14, Smirnov admitted that officials associated with Russian intelligence were involved in passing a story about Businessperson 1,� the prosecution memo states. Businessperson 1 is Hunter Biden, according to people familiar with the case who spoke on the condition of anonymity because they were not authorized to discuss it.

The memo goes on to say that Smirnov has repeatedly claimed close links with Russian intelligence officials, and even planned to meet with Russian intelligence shortly after his trip to the United States. And in conversations with the FBI in late 2023, the court filing says, he suggested that Russian officials “may use as ‘kompromat’ in the 2024 election� the contents of allegedly intercepted phone calls of Hunter Biden in a foreign hotel.

“Smirnov’s efforts to spread misinformation about a candidate of one of the two major parties in the United States continues,� the detention memo states. “What this shows is that the misinformation he is spreading is not confined to 2020. He is actively peddling new lies that could impact U.S. elections after meeting with Russian intelligence officials in November. In light of that fact there is a serious risk he will flee in order to avoid accountability for his actions.�

The filing does not make clear what, if any, of Smirnov’s claims the government believes may be true — only that investigators believe he repeatedly lied to them over an extended period of time, and that many of those lies concerned the Biden family and Ukraine.

People familiar with the Biden investigation, speaking on the condition of anonymity to describe details they were not authorized to disclose, have long said that when Smirnov first made the Burisma-Biden allegations to the FBI in 2020, the allegations were looked into and then dropped as unfounded.

The informant told FBI agents that he knew of conversations from 2015 or 2016 in which Burisma executives said they hired the Biden son “to protect us, through his dad, from all kinds of problems,� and that the father and son were each paid $5 million, the indictment alleges. It goes on to say those alleged conversations never happened.

Nevertheless, Smirnov’s account was passed along to Weiss’s investigators because they were investigating Hunter Biden.

U.S. authorities said that when agents questioned Smirnov again in 2023, he repeated some past lies, changed other parts of his story and offered new falsehoods after claiming to have spoken to Russian officials.

Last year, Weiss asked Attorney General Merrick Garland to appoint him as a special counsel, which formally gave him more independence in charging decisions. He subsequently charged Hunter Biden in Delaware with lying on gun purchase forms years ago. Weiss has also charged Hunter Biden in federal court in Los Angeles with multiple tax crimes.

Last week Weiss announced charges against Smirnov, and this week he pressed to keep the former informant in jail until his trial.