The president made a Sunday evening visit to the Wilmington, Delaware, home of Hallie Biden, the widow of his elder son, Beau, and former girlfriend of Hunter, ahead of her expected testimony in the Delaware gun prosecution of his son. 

Ms. Biden was married to Beau for 13 years before his death in 2015, and had a relationship with her former brother-in-law betwen 2016 and 2019. She was dating Hunter when he was actively addicted to drugs in the wake of his brother’s death. She is also the one who found Mr. Biden’s gun, likely making her the prosecution’s key witness.

The White House announced Sunday night that the president had made an unscheduled stop at his daughter-in-law’s home while he was on the way to the Delaware National Guard Station, where he would take Marine One to Washington, from his Delaware estate. 

The White House and Hunter Biden’s defense team did not immediately respond to requests for comment about the nature of the visit. Hallie and Beau’s two children, ages 18 and 19, live with their mother. They are the president’s grandchildren.

Ms. Biden has already been called to testify about her relationship with Mr. Biden at the time he purchased a firearm in 2018 and possessed it for 11 days. It was Ms. Biden who, according to Politico, found the gun in Mr. Biden’s truck and discarded it in a trash receptacle outside a Wilmington, Delaware, supermarket for fear that Mr. Biden would harm himself or others. It was her fateful decision to dispose of the gun that brought its purchase to the attention of law enforcement, eventually leading to Mr. Biden facing multiple felony charges.

In addition to having found the gun, Ms. Biden was a witness to Mr. Biden’s serious drug addiction at the time, which he described in his memoir, “Beautiful Things.”

The reaction to the White House announcement from some of the president’s biggest fans online was fierce. One NBC News producer, Gary Grumbach, noted the president’s visit, and Ms. Biden’s status as a witness, in a post on X, formerly known as Twitter, on Sunday evening. He was widely denounced on the platform by Biden supporters who pointed out that it is close to the anniversary of Beau’s death, and that Memorial Day weekend was an appropriate time for a visit to his son’s family since he had served in the military. 

The prosecution announced in a court filing on May 20 that “Witness 3” — who is anonymous but matches the description of Ms. Biden — would take the stand during the trial to “authenticate” text messages recovered from Mr. Biden’s laptop and iCloud account. The messages show that Mr. Biden was using drugs at the time he purchased and possessed the firearm. 

“Witness 3 was in a romantic relationship with the defendant in October 2018, and before and after. Witness 3 observed the defendant using drugs on multiple occasions. When he stayed at her home in the fall of 2018, Witness 3 and her children searched his bags, backpacks, and vehicle in an effort to help him get sober, and discovered drug paraphernalia and drugs in his possession on multiple occasions,” Mr. Weiss’s office writes. 

“Witness 3 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,” the filing continues. 

Some of the text messages included in the prosecution’s exhibit includes details about Mr. Biden’s frequent drug use and even photos of what appears to be powder cocaine. 

“Please be safe my love,” one message from a phone number — presumably Ms. Biden’s — sent to the first son reads. “I just want you to be safe.”

“Why won’t you answer my calls? Where are you? Are you with someone?” a text from the same number asked Mr. Biden. He responded by saying he was waiting for a dealer “named Mookie.” 

“I was sleeping on a car smoking crack on 4th street and Rodney,” Mr. Biden wrote to the number the following day. “There’s my truth.”

The number responded: “I just want to help you get sober, nothing I do or you do is working. I’m sorry.” In the next message, the number texted, “I am afraid you are going to die.”