WILMINGTON, Delaware — In a win for Hunter Biden’s defense team, Hallie Biden on Thursday said she did not see the first son smoking crack around the time he purchased the Colt Cobra .38 Special on October 12, 2018. Ms. Biden testified about the depth of her ex-boyfriend’s crack addiction, his lies, and his inability to maintain sobriety, however. 

Ms. Biden and Mr. Biden were in a romantic relationship over the course of several years following the death of her husband, Beau Biden, the president’s eldest son, from brain cancer in 2015. Ms. Biden confirmed on the stand that she was the one who “panicked” and threw away the gun, after she found it in Mr. Biden’s truck, because she feared for her then-boyfriend’s safety. 

Ms. Biden, who has been granted immunity by the prosecution to speak freely about the incident, also disclosed that she herself began smoking crack thanks to her then-boyfriend. She testified on Thursday that during a trip to visit Mr. Biden at Los Angeles in the summer of 2018, the first son and Ms. Biden smoked crack together in the iconic Roosevelt Hotel. 

During the course of their relationship, she saw Mr. Biden smoke crack many times and said he was once nearly caught by one of her children. Sometimes he would be “agitated” after smoking and other times he would be “functioning,” Ms. Biden said. 

Ms. Biden said it was “terrible” and that she is “embarrassed” and “ashamed” about that period of her life. After using the drug for several months, Ms. Biden says she quit in August 2018. She and Mr. Biden broke up the next year. Ms. Biden quietly remarried last weekend to a financier divorcee, John Anning, whom the Daily Mail describes as a “lookalike” to Mr. Biden. Mr. Anning has been accompanying her to court.

One of the prosecution’s more damning pieces of evidence, which prosecutors say shows Mr. Biden was using crack while in possession of the gun, are texts from the first son to Ms. Biden the day after he bought the Colt handgun. In the texts, Mr. Biden tells her that he was waiting for a dealer named “Mookie” while “sleeping on a car smoking crack.”

Mr. Biden’s attorney, Abbe Lowell, asked Ms. Biden if she knew for a fact if Mr. Biden was using that day, or if he was lying. Ms. Biden had asked him in another text where he was “truthfully” because Mr. Biden would often lie about what he was doing or where he was. Ms. Biden told the jury that she did not know for a fact if Mr. Biden was actually smoking crack and waiting for Mookie. Mr. Lowell has been setting himself up to make the argument that Mr. Biden, at the time he purchased the gun in 2018, was an untrustworthy liar who was briefly sober, and that none of the text messages recovered from his now notorious laptop or his iPhone should be taken at face value. 

On the morning of October 23 — 11 days after Mr. Biden bought the gun — Ms. Biden said he arrived at her home looking “exhausted” and immediately went to bed. When she was cleaning out his truck, fearful of what she might find, she discovered the handgun and began “panicking,” she said. 

The courtroom was silent as a prosecutor, Leo Wise, played a grainy surveillance video of Ms. Biden disposing of the gun, which was contained in a brown leather pouch, outside an upscale grocery store at Wilmington, near her home. 

She could not recall how Mr. Biden found out that she had disposed of the weapon, but testified that he grew “angry” almost immediately, realizing the trouble he could be in, and told her to go “look for it.” When Ms. Biden could not find the gun, which has been discovered by a scavenger looking for cans, Mr. Biden told her to file a police report. 

Mr. Lowell has been making the argument that Mr. Biden was sober at the moment he purchased the gun, and that there are no witnesses who can testify that he was smoking crack on October 12. Before Ms. Biden took the stand, Mr. Lowell cross-examined another prosecution witness — the man who sold Mr. Biden the gun, Gordon Cleveland. 

Mr. Cleveland testified that the Bureau of Alcohol, Tobacco, and Firearms form that Mr. Biden filled out to get his gun asks: “Are you a user” of drugs, not “have you been” a user of drugs. Mr. Lowell says Mr. Biden was being honest when he filled out that form because at the time, he was not actively smoking crack and was seeking treatment along with Ms. Biden. 

After Ms. Biden’s testimony concluded, the jury heard from more prosecution witnesses including a Delaware state trooper, Joshua Marley, who was called to investigate the disposal of the weapon and later participated in an interview with Mr. Biden about the disappearance of the gun. Mr. Marley’s testimony lasted just a few minutes. 

A former officer, Miller Greer, also testified briefly on Thursday about recovering the weapon from a local retiree, Edward Banner, who had found it while rummaging through a dumpster.

Mr. Banner, a Navy veteran, then took the stand and told jurors about finding the gun, ammunition, and speed loader with a brown leather pouch in the Dumpster. He picked up collecting recyclables from trash bins as a hobby in his golden years, and as a way to make some extra money. 

Mr. Banner said that when law enforcement made contact with him, he pulled the firearm and its accompanying parts from his sock drawer and had

The prosecution announced that they have just two more witnesses to call to the stand on Friday before resting their case. 

During Ms. Biden’s testimony, the defendant paid close attention, unlike when other witnesses were on the stand during the course of the trial. At one point, Mr. Biden leaned forward in his chair at the defense table and placed his hands under his chin. 

Members of the first family were in attendance on Thursday, including Mr. Biden’s wife, Melissa Cohen, who did not react to much of the day’s testimony. Mr. Biden’s aunt, Valerie Owens — the president’s younger sister — sat in the audience later in the day, seemingly taking the place of the first lady, who has attended every day of the trial but is now in France for the 80th anniversary of D-Day. Mr. Biden’s friend and benefactor, Kevin Morris, also sat among family members of the defendant. The first lady will return to Delaware from France on Thursday night to attend Mr. Biden’s trial before returning for a state dinner at Paris this weekend. 

In an interview with ABC News, which is expected to air on Thursday evening, President Biden said he would respect the will of the jury and that he would not pardon his son if he is found guilty.