Hunter Biden has been indicted on nine tax charges in California , the second indictment against the president’s son, adding fuel to a scandal that Republicans have been seizing on in the lead-up to the 2024 election.

The state charges on Thursday follow federal firearms charges in Delaware alleging Hunter Biden unlawfully obtained a revolver in October 2018 after he falsely stated he was not using narcotic drugs.

The new charges include three felonies and six misdemeanor offenses, and Biden faces a possible 17-year sentence if convicted.

“The Defendant engaged in a four-year scheme to not pay at least $1.4 million in self-assessed federal taxes he owed for tax years 2016 through 2019,” the 56-page indictment said, adding that Biden “spent millions of dollars on an extravagant lifestyle rather than paying his tax bills”.

He had previously been expected to plead guilty to misdemeanor tax charges as part of a plea deal with prosecutors who said he failed to pay taxes on $4m in personal income in 2017 and 2018.

But the agreement imploded in July after a judge raised questions about it. The deal had been pilloried as a “sweetheart deal” by Republicans, who have been investigating nearly every aspect of Hunter Biden’s business dealings as well as the justice department’s handling of the case.

The state charges come as Republicans in Congress have pushed forward with a possible impeachment inquiry into Joe Biden in connection with his son’s scandals. The House is on track to vote next week on authorizing a formal inquiry, although no evidence has emerged so far to prove that the president accepted bribes or engaged in an influence-peddling scheme, as some GOP representatives have suggested.

Some Republicans have expressed doubt about a possible impeachment, questioning whether a case is merited. In September, witnesses brought in by Republicans on the House oversight committee said there was no evidence of crimes by Joe Biden, but also called for further investigation.

Hunter Biden pleaded not guilty to the gun charges in Delaware, which marked the first time a sitting US president’s child faced criminal prosecution. His lawyer said at the time that the special counsel was “bending to political pressure” by filing the indictment.

The new case is set to add chaos to what will already be an extraordinary election year, in which the sitting president will be dealing with the fallout of his son’s possible trials, while his likely opponent, Donald Trump, is facing four separate criminal cases and 91 charges.