Hallie Biden arrives to court

Hallie Biden, widow of Beau Biden and former girlfriend to Hunter Biden, arrives with her fiancé John Hopkins Anning, at federal court during Hunter’s trial for criminal gun charges in Wilmington, Delaware, on June 6, 2024. (REUTERS/Kevin Lamarque)

Hallie Biden, Hunter Biden's sister-in-law, arrived to court Thursday morning for day four of Hunter Biden's federal gun crime trial.

Hallie is among several potential witnesses who are expected to be called by the prosecution to testify in Hunter's trial. The pair were in a romantic relationship in 2018.

Hallie observed Hunter Biden using drugs on multiple occasions, according to prosecutors, and she and her children discovered drug paraphernalia and drugs in his possession when they searched his bags, backpacks and vehicle in an effort to help him get sober.

Hallie, prosecutors said ahead of the trial, "observed that the defendant frequently lost phones and changed phones, which explains gaps in time where there are no messages, and she also had various text message exchanges with the defendant."