WILMINGTON, Del. - The criminal trial of President Joe Biden’s son heads into its final stretch Monday as the defense tries to chip away at prosecutors’ case laying bare some of the darkest moments of Hunter Biden’s drug-fueled past.

Hunter Biden’s lawyers could call at least one more witness when the case resumes in Delaware’s federal court - the first of two trials he’s facing in the midst of his father’s reelection campaign. It’s unclear whether prosecutors will call any rebuttal witnesses before the case goes to closing arguments, and then to the jury.

Hunter Biden is charged with three felonies stemming from the October 2018 purchase of a gun he had for about 11 days. Prosecutors say he lied on a mandatory gun-purchase form by saying he was not illegally using or addicted to drugs.

Hunter Biden has pleaded not guilty and has accused the Justice Department of bending to political pressure from former President Donald Trump and other Republicans to bring the case and separate tax charges after a deal with prosecutors fell apart last year. Hunter Biden has said he has been sober since 2019, but his attorneys have said he did not consider himself an “addict” when he filled out the form.

The case has put a spotlight on a turbulent time in Hunter Biden’s life after his brother Beau’s 2015 death. First Lady Jill Biden has watched it unfold from the front row of the courtroom. President Biden was away in France last week, and heads to Europe again this week for the Group of Seven leaders meeting in Italy.

Hunter Biden’s struggles with a substance addiction, before getting sober more than five years ago, are well documented. Defense lawyers argue there’s no evidence Hunter Biden was actually using drugs in the 11 days that he possessed the gun. He had completed a rehab program weeks earlier.

Jurors have heard emotional and tawdry testimony from Hunter Biden’s former romantic partners and read personal text messages. They’ve seen photos of Hunter Biden holding a crack pipe and partly clothed, and video from his phone of crack cocaine weighed on a scale.

His ex-wife and two onetime girlfriends testified for prosecutors about his habitual crack use and their failed efforts to help him get clean. One woman, who met Hunter Biden in 2017 at a strip club where she worked, described him smoking crack every 20 minutes or so while she stayed with him at a hotel.

Hunter Biden hasn’t taken the witness stand and it’s unclear if he will. But jurors have heard him describe at length his descent into addiction through audio excerpts played in court of his 2021 memoir “Beautiful Things.” The book, written after he got sober, covers the period he had the gun, but doesn’t mention it specifically.

A key witness for prosecutors is Beau’s widow, Hallie, who had a brief troubled relationship with Hunter after his brother died of brain cancer. She found the unloaded gun in Hunter’s truck on Oct. 23, 2018, panicked and tossed it into a garbage can at a grocery store in Wilmington, where a man inadvertently fished it out of the trash.

“I didn’t want him to hurt himself, and I didn’t want my kids to find it and hurt themselves,” Hallie Biden told jurors.