Wilmington, Delaware - Jurors at Hunter Biden's trial heard testimony Wednesday from an FBI agent who investigated President Joe Biden's son for allegedly buying a handgun while using crack cocaine.

On Tuesday the court heard that Hunter Biden – the first child of a sitting US president to be prosecuted – was a heavy drug user and allegedly lied about this on the paperwork when purchasing the firearm.

He is also on trial in federal court in Wilmington, Delaware – his family's political heartland – for illegal possession of the firearm, which he had for just 11 days in October 2018.

FBI Special Agent Erika Jensen testified how investigators retrieved evidence, including photographs apparently showing drugs, from a now infamous abandoned laptop that has been at the heart of Republican efforts to discredit the Biden family.

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Hunter Biden's ex-wife Kathleen Buhle could take the stand after Jensen according to the outline of the case given by the prosecution on Tuesday.

First Lady Jill Biden was again in court Wednesday as she has been for every day of the trial, while President Joe Biden has issued a statement saying he is "proud" of his son.

The case has been a distraction for Biden's reelection campaign against Donald Trump. The president was in France on Wednesday to attend World War II D-Day commemorations and is in the midst of rolling out major initiatives on illegal migration into the US and a proposed truce for Gaza.

The trial comes just days after Trump was convicted in a New York court on business fraud charges.

On Tuesday, the prosecutor in Wilmington played extracts from an audio version of Hunter Biden's memoir Beautiful Things, recorded by Biden himself, in which he recalled his descent into addiction when he would desperately seek out crack cocaine.

"I cooked [crack] and smoked. I cooked and smoked," said the extract played to the court, taken from his audiobook.

But Hunter Biden's lawyer said that he "was not using drugs when he bought that gun" and that it "was never loaded, never carried, never used" during the 11 days he owned it.

Biden, a Yale-trained lawyer and lobbyist-turned-artist, has stated that he has been sober since 2019.

The legal woes have reopened painful emotional wounds for the Biden family, stemming from his time as a drug addict and well before.

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His brother Beau died from cancer in 2015, and his sister Naomi died as an infant in a 1972 car crash that also killed their mother, Neilia, Joe Biden's first wife. Hunter and Beau were the only survivors of the accident.

If found guilty, Hunter Biden could face 25 years in prison – although, as a first-time offender, jail time is unlikely.

The president's son has long been the target of hard-right Republicans trying to embarrass Joe Biden, and Trump allies have investigated him at length in Congress on allegations of corruption and influence-peddling. No official charges have ever been brought.

Hunter Biden's business dealings in China and Ukraine have also formed the basis for attempts by Republican lawmakers to initiate impeachment proceedings against his father. Those efforts have so far gone nowhere.

The White House said last year that there would be no presidential pardon for Hunter Biden in case of a conviction.