WASHINGTON (AP) — An FBI informant has been charged with fabricating a multimillion-dollar bribery scheme involving President Joe Biden, his son Hunter and a Ukrainian energy company, a claim that is central to the Republican impeachment inquiry in Congress.

Alexander Smirnov falsely reported to the FBI in June 2020 that executives associated with the Ukrainian energy company Burisma paid Hunter and Joe Biden $5 million each in 2015 or 2016, prosecutors said in an indictment. Smirnov told his handler that an executive claimed to have hired Hunter Biden to “protect us, through his dad, from all kinds of problems,” according to court documents.

Prosecutors say Smirnov in fact had only routine business dealings with the company in 2017 and made the bribery allegations after he “expressed bias” against Joe Biden while he was a presidential candidate.

Smirnov, 43, appeared in court in Las Vegas briefly Thursday after being charged with making a false statement and creating a false and fictitious record. He did not enter a plea. The judge ordered the courtroom cleared after federal public defender Margaret Wightman Lambrose requested a closed hearing for arguments about sealing court documents. She declined to comment on the case.

The informant’s claims have been central to the Republican effort in Congress to investigate the president and his family, and helped spark what is now a House impeachment inquiry into Biden. An attorney for Hunter Biden, who is expected to give a deposition later this month, said the charges show the probe is “based on dishonest, uncredible allegations and witnesses.”