Hunter Biden was charged last month with three counts related to lying on a federal form to acquire a Colt Cobra handgun in 2018 and for being an illegal drug user in possession of the gun.

Hunter Biden was indicted for allegedly lying on a form to acquire a handgun in 2018 and for being an illegal drug user in possession of the gun.

Hunter Biden is the first child of a sitting US president to have been criminally indicted.

Prosecutors accuse the younger Biden of lying about his use of narcotics when he purchased a Colt Cobra handgun in October 2018.

The lawsuit accuses Garrett Ziegler, a former aide to Trump trade adviser Peter Navarro, of violating California's computer fraud and data access laws, and demands a jury trial.

A potential trial raises the possibility of the son of a sitting president facing criminal charges while his father campaigns for re-election, likely against Donald Trump, who faces at least three upcoming criminal trials of his own.

According to court filings, Hunter Biden received taxable income in excess of US$1.5 million in 2017 and 2018, but he did not pay income tax those years despite owing in excess of US$100,000.

The investigation was disclosed just five days before the Electoral College is expected to formally select Joe Biden as the next president.