Hunter Biden has arrived at the Wilmington courthouse for today's proceedings.

Like previous days, he was accompanied by his wife, Melissa Cohen Biden.

The gun store clerk who sold Hunter Biden the handgun at the center of the government's case returns to the witness stand this morning on Day 4 of the trial as prosecutors look to wrap up their case against the president's son.

Prosecutors said at the end of Wednesday's proceedings that they plan to call six more witnesses -- including Hallie Biden, perhaps their most crucial witness -- before resting their case, which could happen as soon as this afternoon.

Defense counsel have leaned into their claim that Hunter Biden was not actively abusing drugs in October of 2018, the month of his gun purchase, and therefore did not knowingly lie on the federal firearm application form.

Zoe Kestan, one of Hunter Biden's ex-girlfriends, testified Wednesday that she witnessed him smoking crack the month before and the month after his gun purchase, but had "no idea" what he was doing in October.

To fill that gap, prosecutors plan to call Hallie Biden, his brother's widow with whom Hunter Biden was romantically involved.

"The evidence will show that during those 11 days, the defendant continued to use drugs and to talk about his drug use with Hallie," prosecutor Derek Hines said.

Under cross-examination by defense attorney Abbe Lowell, gun store clerk Gordon Cleveland testified about the sequence of events on Oct. 12, 2018, when he sold Hunter Biden the handgun at the center of the case -- with Cleveland and Lowell at times squabbling over details as granular as the direction of Hunter Biden's vehicle when he drove into the store's parking lot.

Cleveland will return to the stand Thursday morning when proceedings continue.

Prosecutor Derek Hines told the judge before court concluded for the day that he anticipated resting his case as soon as the end of the day on Thursday. The government has six brief witnesses remaining, he said.

Lowell said that if the government rests its case by the end of the day Thursday, he would be prepared to call his first witness on Friday morning.

Gun store clerk Gordon Cleveland testified that he watched from "about two feet" away as Hunter Biden, in the course of purchasing a handgun in 2018, filled out Form 4473 and checked the box asking applicants whether they were active drug users.

After Hunter Biden selected the Colt Cobra for purchase, Cleveland said he asked him to fill out Form 4473, which he told him was required for "every gun purchase." Cleveland testified that he instructed Hunter Biden to write in his personal information and answer the questions below, "and to take your time answering them," he said.

Cleveland testified that he watched as Hunter Biden answered several questions on the form before he approached question 11.E., which asked about drug use.

"You saw him strike that box with an 'X'?" prosecutor Derek Hines asked.

"Yes," Cleveland said.

"He didn't seem to express any confusion by that question?" Hines asked.

"No," Cleveland said.

Prosecutor Leo Wise used witness testimony and Hunter Biden's own words from his memoir and text messages to argue that the president's son "knew exactly what he was doing" when prosecutors say he falsely claimed he was not addicted to drugs in order to purchase a Colt handgun in 2018.

"Take the defendant's word for it," Wise said as he showed the jury excerpts from Hunter Biden's book that described his drug use and addiction.

Wise, showing the jurors a side-by-side comparison of testimony regarding his truck from his daughter Naomi Biden and then-girlfriend Hallie Biden, said their testimony is "circumstantial evidence " that shows "the defendant used crack in the truck" days after purchasing the firearm.

Naomi Biden testified that she returned the truck to her father "clean" on Oct. 19, 2018, and Hallie Biden testified that a few days later she found Hunter Biden's gun in the vehicle along with drug paraphernalia and drug remnants.

Wise also showed the jury a calendar of the month of October 2018 that showed the cash withdrawals made by Hunter Biden. "None of the cash was for rehab," Wise said.

The evidence, Wise told jurors in conclusion, "supports only one verdict."

Hunter Biden's attorney Abbe Lowell then began his closing arguments.