WASHINGTON — A former FBI informant is set to plead guilty on Monday to lying about a phony bribery scheme involving President Joe Biden and his son Hunter that became central to the Republican impeachment inquiry in Congress.

Alexander Smirnov is expected to make the plea in Los Angeles to a felony charge in connection with the bogus story, along with a tax evasion charge stemming from a separate indictment accusing him of concealing millions of dollars of income, according to court papers.

Smirnov has been behind bars since his arrest in February on charges that he told his FBI handler that executives from the Ukrainian energy company Burisma had paid President Biden and Hunter Biden $5 million each around 2015.

Prosecutors and the defense have agreed to recommend a sentence of between four and six years in prison, according to the plea agreement.

Smirnov had been an informant for more than a decade when he made the explosive allegations about the Bidens in June 2020, after “expressing bias” about Joe Biden as a presidential candidate, prosecutors said.

But Smirnov had only routine business dealings with Burisma starting in 2017, according to court documents. An FBI field office investigated the allegations and recommended the case be closed in August 2020, according to charging documents.

No Evidence Emerged That Biden Acted Corruptly in White House

No evidence has emerged that Joe Biden acted corruptly or accepted bribes as president or in his previous office as vice president.

While Smirnov’s identity wasn’t publicly known before the indictment, his claims played a major part in the Republican effort in Congress to investigate the president and his family, and helped spark a House impeachment inquiry into Biden. Before Smirnov’s arrest, Republicans had demanded the FBI release the unredacted form documenting the unverified allegations, though they acknowledged they couldn’t confirm if they were true.

During a September 2023 conversation with investigators, Smirnov also claimed the Russians probably had recordings of Hunter Biden because a hotel in Ukraine’s capital where he had stayed was “wired” and under their control — information he said was passed along to him by four high-level Russian officials.

But Hunter Biden had never traveled to Ukraine, according to Smirnov’s indictment.

Smirnov claimed to have contacts with Russian intelligence-affiliated officials, and told authorities after his arrest this year that “officials associated with Russian intelligence were involved in passing a story” about Hunter Biden.

The case against Smirnov was brought by special counsel David Weiss, who also prosecuted Hunter Biden on gun and tax charges. Hunter Biden was supposed to be sentenced this month after being convicted at a trial in the gun case and pleading guilty to federal charges in the tax case. But he was pardoned this month by his father, who said he believed “raw politics has infected this process and it led to a miscarriage of justice.”