A former informant has pleaded guilty to lying to the US Federal Bureau of Investigation (FBI) about a fake bribery scheme between President Joe Biden and his son Hunter.

Alexander Smirnov, 44, also admitted tax evasion after failing to report income of more than $2 million (£1.58 million).

His allegations became the basis of a congressional impeachment inquiry that focused on false allegations that the Bidens received millions of dollars in bribes from Burisma, a Ukrainian energy company.

But Smirnov admitted he made up the story and pleaded guilty Monday in Los Angeles as part of a deal with prosecutors.

Smirnov, a dual American-Israeli citizen, had been an FBI informant for more than a decade when he made the allegations against the Bidens in June 2020, saying that Joe and Hunter Biden each received $5 million from the energy company.

Prosecutors said Smirnov was motivated by “bias” against President Biden and turned his “routine and extraordinary business contacts” with Burisma into bribery stories that were “factories.”

The FBI investigated his statements but within months recommended closing the case without taking legal action against the Bidens.

But the allegations refused to be suppressed and became the basis for a Republican-led investigation into President Biden, including an attempt to make Smirnov’s first statement public.

Prosecutors say Smirnov doubled down on his claims when he was questioned again by FBI agents in September 2023.

Smirnov was arrested in Nevada when he returned to the United States from a trip abroad in February 2024.

According to court documents, he had ties to Russian intelligence and used his unreported income of more than $2 million to buy a Las Vegas condo, a Bentley car lease and hundreds of thousands of dollars in clothing, jewelry and accessories .

The case was filed by special counsel David Weiss, who oversaw an investigation into Hunter Biden.

Joe Biden pardoned his son, who was facing prison time for tax evasion and lying on a form about his drug addiction while buying a gun.

Smirnov will be sentenced in January. The plea agreement requires approval from a federal judge.

He faces a maximum sentence of 35 years in prison and a $1 million fine. However, prosecutors and defense attorneys agreed to a sentence of between four and six years and $675,502 in restitution, according to the plea agreement.

The BBC contacted Smirnov’s lawyers for comment.