In dramatic testimony, Hunter Biden's former romantic partner Hallie Biden described how, on the morning of Oct. 23, 2018, she went to go "clean out" Hunter Biden's car and found a gun.

"What did you find, in addition to trash and clothes?" prosecutor Leo Wise asked her.

"Remnants of crack cocaine and some paraphernalia," Hallie recounted. "Oh and the gun, obviously."

Hallie Biden said she found the firearm in "the arm console" of the car, which she said was not locked because "the lock had been broken." She said it was the first time she had ever seen a gun. She also found ammunition.

"I panicked, I wanted to get rid of them," she told the jury.

Asked why she panicked, Hallie Biden said she "didn't want him to hurt himself." She said she also worried about her kids finding the gun, saying she considered "hiding" it somewhere but was worried they would find it.

She said those frantic moments led to her throwing the gun in the trash. She told the jury she found a pouch to put it in -- which authorities say later tested positive for having cocaine on it -- and put the gun inside. The jurors were then shown the brown pouch she used.

"I was afraid to kind of touch it, I didn't know if it was loaded," Hallie Biden said, telling jurors she then put the pouch into another bag.

"I took it to the grocery store up the road and I threw it away," she testified.

At this point, jurors were shown surveillance video from the grocery store showing Hallie Biden throwing the gun into the trash.

In the video, her car is seen pulling into the parking lot; she then gets out of the driver's seated, opens the back door to get out the gun, then walks over to the store and places the bag in a garbage receptacle.

"Is that you Mrs. Biden?" prosecutor Leo Wise asked about her image on the video. "Yes," she replied.

Hunter Biden, sitting at the defense table, appeared to be locked on Hallie Biden the entire time, his head resting in his hand. He periodically covered his mouth.

Hunter Biden's former romantic partner Hallie Biden told jurors that Hunter Biden was "tired, exhausted, and looked like he hadn't slept" on the evening of Oct. 22 or early morning of Oct. 23, 2018, when he arrived at her home in Wilmington to sleep.

She observed that he "could've been" on drugs when she saw him -- just hours before she found his newly purchased Colt Cobra revolver in his car and discarded it in a dumpster.

"I went to clean out his car and his stuff" as he slept in her home, in hopes that when he awoke they could "start anew and deal with stuff," she testified, referring to his addiction to "both" drugs and alcohol.

The testimony didn't appear to be quite the smoking gun sought by prosecutors, who are trying to prove Hunter Biden was using crack at the time of his firearm purchase on Oct. 12 -- one of the central questions in the case.

Hallie Biden, who is the widow of Hunter Biden's late brother Beau Biden, testified that earlier in 2018 she also became addicted to crack after Hunter Biden introduced her to the drug -- but that she is now clean.

"It was a terrible experience I went through," she said, adding that she was "embarrassed and ashamed, and I regret that period of my life."

Hallie Biden, Hunter Biden's former romantic partner who is the widow of his brother Beau Biden, has taken the stand as the prosecution's next witness.

Prosecutors have said they expect her to testify about Hunter Biden's drug at the time of his gun purchase in October 2018.

Before gun store clerk Gordon Cleveland stepped off the stand, he testified that Hunter Biden did not exhibit any symptoms of drug or alcohol abuse when he purchased the gun at the center of the case.

When asked by defense attorney Abbe Lowell if Hunter Biden exhibited any symptoms at the time of his gun purchase, such as being "glassy eyed" or smelling of alcohol, Cleveland replied, "None at all."

Cross-examining gun store clerk Gordon Cleveland, defense attorney Abbe Lowell asked about the framing of the various questions on the gun form that Hunter Biden is accused of lying on -- including the difference between "have you" and "are you."

The form, for example, asks the applicant if they "have ever" been convicted -- but asks "are you" an unlawful user of drugs.

The defense team has used this to argue that Hunter Biden could have reasonably believed he was not violating any laws when he checked "No" on the drug-use box, because they say he was not currently using drugs.

"It does not say, 'Have you ever,"' Lowell said.

In court today, Hunter Biden has been attentive and focused, watching as attorneys clashed earlier over evidence. He gripped his pen as prosecutor Leo Wise asked the judge to keep out texts that his team wishes to use when they cross-examination Hallie Biden.

Special counsel David Weiss, who brought the case, has been seated in the front row behind his prosecution team, periodically nodding along as they make their arguments.

According to a transcript of Tuesday's proceedings released hours after court concluded, at attorney for Hunter Biden told the judge during a sidebar conversation that he might decide to call Hunter Biden's oldest daughter, Naomi Biden, to testify at trial "if need be."

Attorney Abbe Lowell made the statement during what appeared to be a tense exchange between him, Judge Maryellen Noreika and two government prosecutors, in which Lowell divulged his expectations for witnesses.

When prosecutors suggested Lowell was hiding the ball on how he planned to present certain evidence, Lowell first introduced the idea of calling one of Hunter Biden's daughters as a witness:

MR. HINES: Exactly, we have asked Mr. Lowell and he won't tell us.
MR. LOWELL: That's not what I said.
MR. HINES: He couldn't tell us which witness.
MR. LOWELL: I said I'm making a proffer and the court -- I understand the rules, each one of these will be submitted with a witness, I don't have to tell them in advance which witness it is, but I am making a statement to the Court, there is three or four witnesses, including his uncle and his daughter, if need be.

Lowell later clarified that Naomi Biden, Hunter Biden's daughter with ex-wife Kathleen Buhle, and the president's eldest granddaughter, was on his witness list.

Lowell also left the door open for Hunter Biden to testify "if it gets to that," a gamble that would put his client in the position of facing live cross-examination from federal prosecutors. It came during a discussion about how Lowell planned to demonstrate that Hunter Biden read the ATF Form 4473 "carefully."

THE COURT: Wait. Just so I'm clear, are you going to suggest that he did in fact read these things or just that if he had chosen to and didn't tell them.
MR. LOWELL: Both.
THE COURT: What is your evidence going to be that he did in fact read all of these things carefully?
MR. LOWELL: If it gets to that judge, then it will be Mr. Biden's job to say that.

During a debate at the same bench conference about an argument Lowell intended to make in his opening statement, Judge Maryellen Noreika called the defense attorney for interrupting her.

MR. LOWELL: That's not the argument judge.
THE COURT: That is what it sounds like you're telling me, you're saying he doesn't know what it was.
MR. LOWELL: No.
THE COURT: You keep cutting me off, and you want to make your argument, and I know you want to make your argument, but you need to understand it, so you need to understand where I am.

The judge later told Lowell, "Don't put words in my mouth."

"I know you're just trying to zealously represent your client," she said, "but don't assume my ruling before you give me a chance to make it."