WILMINGTON, Del. — Kathleen Buhle stood in a beige suit Wednesday and stared through thick-rimmed glasses into the courtroom. Taking the witness stand, she made eye contact with her ex-husband, Hunter Biden, and went on to detail in a sober tone the ways she said his drug use affected her family and changed the man she loved.

In some of the most gripping testimony of the first three days of court proceedings here, Buhle recounted how she combed through Hunter’s cars to remove drug paraphernalia so that their three daughters would not be caught driving with their father’s drugs.

“I found a crack pipe on July 3, 2015, in an ashtray on the side porch of our house,” she said, recalling that this happened the day after their wedding anniversary. “I was worried. Scared.”

In many ways, the trial here is unfolding like a typical legal case, as prosecutors use photos, witness testimony and Biden’s own words to try to prove the charges: that he was in the midst of a serious drug habit five years ago, and therefore lied when he declared on an official form when buying a gun that he was not using illegal drugs.

But the proceeding is also showcasing in stark terms the internal drama that has been an undercurrent in the Biden family for years, as family members and former family members take the stand. In one of the trial’s more striking moments, prosecutors on Tuesday played an audiobook of Biden’s memoir describing his addiction so that the defendant’s own voice filled the room as he listened silently.

Hallie Biden — the widow of President Biden’s son Beau and the mother of two of the president’s grandchildren — is expected to testify Thursday about the crack cocaine that she and Hunter used together during their love affair, something she is doing under a grant of immunity.

The defense has signaled that it may call Naomi Biden, oldest daughter of Hunter and Kathleen, to the stand, meaning she would be taking the opposite side from her mother. Naomi and the president’s brother, James Biden, would be expected to testify about the kindness Hunter has shown and about his continuous efforts to go through rehab.

The trial has clearly been painful for various members of the family. Hunter’s younger sister, Ashley, sat through some of the first two days, occasionally dabbing her eyes, but did not return on Wednesday. First lady Jill Biden has sat through large portions of testimony — often hugging and kissing Hunter during breaks — but was notably absent when Buhle, her former daughter-in-law, took the stand.

On Wednesday, Buhle testified that she found drugs or drug paraphernalia about a dozen times during the couple’s time together, although she said she never saw Hunter Biden actually use drugs. She knew he was using drugs because he told her, Buhle testified.

“He told me when I found the pipe what it was for,” she said. She said he went to rehab for the first time in 2003 and again years later as their marriage was ending.

“He was not himself,” Buhle said of Biden. “He was angry, short-tempered, acting in ways he was not when he was sober.”

Her voice was even, and at times dispassionate, as she recounted the family turmoil. “He moved out, really, after I found the crack pipe,” she said. “But I didn’t consider us separated until I found out about the infidelity.”

A few minutes after Buhle left the courtroom, Zoe Kestan, one of Biden’s former girlfriends, took the stand to describe a whirlwind romance that began when she met him in late 2017 as she and another woman were dancing for him in a private room at a gentlemen’s club in Manhattan called Vivid Cabaret.

Kestan testified under a grant of immunity — meaning as long as prosecutors believe she is telling the truth, nothing she says can be used against her. She recounted that she was struck by how charming Biden was and how he was smoking crack within minutes of meeting her.

Kestan described how even when she and Biden were out in public, at a store or restaurant, he would go into the bathroom or another private place about once an hour to do drugs. When they were alone in a hotel room, she said, his crack smoking was more frequent, about once every 20 minutes.

“He was just so charming and so nice,” Kestan testified. “I felt myself having feelings for him.”

Biden sat through most of the testimony looking straight ahead, glancing at the jury or turning around to check on his wife.

When prosecutors asked Kestan to identify her ex-boyfriend, Biden defused the moment’s seriousness by waving hello to her from the defense table.

Kestan also described photos she had provided prosecutors, including one showing baking soda that she said Biden would mix with cocaine to make crack. A photo from June 2018 showed a shirtless Biden lying passed out in bed with drug paraphernalia on the nightstand next to him.

Under cross-examination by Biden’s lawyer Abbe Lowell, Kestan said she helped him find cocaine in November 2018, locating a college friend in Providence, R.I., who pointed them toward a dealer. Lowell’s questions appeared to be aimed at suggesting that Kestan was a willing participant in and an enabler of Biden’s drug use.

Prosecutors countered by noting that Biden had asked her to get him drugs — and that at the time, he was 48 and she was 24, close in age to his daughters.

President Biden has not attended the trial himself, but the courtroom has been a showcase of family allies who each day have sat along the first two rows.

They have exchanged kisses, warm greetings and embraces when they meet in the morning. They have whispered to each other as the trial has unfolded. Several Secret Service agents have been in the room as well.

On Wednesday, a group of longtime family friends linked hands shortly before the morning’s court proceedings and said a prayer.

“At this hour, the Biden family needs the support of Delaware,” said the Rev. Christopher Alan Bullock, pastor at Canaan Baptist Church. “Tough times require support, prayer and family — not judgment, but love and support.”

Almost every family member has come up during the trial. Potential jurors recalled knowing Beau Biden, Hunter Biden’s brother who died of cancer in 2015, and coaching his children. One uncle — Jack Owens, the husband of the president’s sister — has been at the trial each day. Another — the president’s younger brother, James, called Jimmy by the family — plans to testify.

On the other side of the courtroom from the Biden family has sat David C. Weiss, the special counsel who has pursued the charges against Hunter Biden and who was appointed to his special counsel role by the president’s attorney general, Merrick Garland.

Not all the drama has been in the courtroom. During a break in proceedings on Tuesday, Biden’s wife, Melissa Cohen, approached Garrett Ziegler, a former Trump aide who has compiled embarrassing information about her husband and posted it online.

“You have no right to be here, you Nazi!” she told him, according to an NBC reporter who witnessed the exchange.

Ziegler later told NBC News, “It’s sad. I’ve been sitting here the whole time and haven’t approached anyone.”

“For the record, I’m not a Nazi,” he added. “I’m a believer in the U.S. Constitution. I haven’t said one thing to them.”

But for all the intrigue, the legal case itself revolves around the dry details of a federal gun form and prosecutors’ attempt to prove Biden lied when he filled it out Oct. 12, 2018.

On Wednesday afternoon, Gordon Cleveland, a trash truck driver who used to work part time as a salesman in a Wilmington gun shop, testified that he had sold Biden a Colt .38 special in October 2018 — the transaction at the heart of the trial.

Cleveland said he remembered sitting at the window, noticing a black Cadillac pull up to the store. Asked how he remembered that detail from years ago, Cleveland said, “I like guns and I like cars, two things I’m really into,” prompting some laughter in the courtroom.

Biden, whom he did not know or recognize, came into the store said he was looking for a revolver, Cleveland recounted. After looking at Rugers, he chose the Colt, and Cleveland gave him Form 4473 — the federal paperwork would-be gun buyers must fill out.

Question 11E of the form asks: “Are you an unlawful user of or addicted to … any controlled substance?” Cleveland said he watched Biden fill out the form, including answering that question by checking “No.”

Prosecutor Derek Hines asked if there was any confusion on Biden’s part about the form. “No,” Cleveland said.

When the prosecutor asked Cleveland if he could see Biden in the courtroom, Biden waved at him, just as he had to Kestan earlier in the day.

“Yes, he’s over there,” Cleveland responded. “Waving.”

During cross-examination, Lowell tried to cast Cleveland as a persuasive salesman who attempted to sell Biden a gun and accessories that he knew little about. Lowell was apparently trying to back up his previous argument in court that Biden had been waiting for a phone from a nearby AT&T store and was only intending to kill time when he walked into the gun shop.

“Are you familiar with the term ‘whale hunter?’” Lowell asked.

Cleveland laughed and responded that his colleagues gave him that nickname because he was good at selling high-end weapons. But he said that while Biden did not seem to know too many specifics about guns, he came to the Delaware shop asking for a revolver.

Cleveland added that he never tried to upsell or sway Biden to buy the particular gun, ammo or the speed loader he ultimately purchased.

The defense contends that Biden never loaded or used the gun. He is not accused of committing a crime with the gun, and the witnesses have not been asked to discuss why he may have wanted to buy it.

Prosecutors did, however, enter the gun into evidence.

The Colt Cobra .38 special, with a silver finish and a black handle, had been rendered safe before becoming a trial exhibit, Hines said. Holding the gun in a white cardboard box, he slowly walked the weapon past the jurors so that they could all see it.