As President Biden forcefully denies involvement with or knowledge of the business practices of his troubled son, Hunter, the president is facing increasing skepticism about his truthfulness on the matter, even as legal scrutiny of the first son mounts daily.

Following the disclosure of an encrypted text message sent by Mr. Biden fils to a business partner in Communist China in which he invokes his father’s name in a threatening tone while demanding money, saying his father was sitting right next to him, the president has denied he knew anything about it.

When asked by Fox News’s White House correspondent, Jacqui Heinrich, on Monday if he was aware of the business in Communist China or his son’s text messages, Mr. Biden quickly denied it. 

“Did you lie about never speaking with Hunter about his business deals?” Ms. Heinrich asked as the president left an event in the East Room of the White House. “No,” he responded sharply. 

During his father’s vice presidency, Mr. Biden engaged in various business ventures in which he’s since been accused of trading on his family name to make money. In 2014, he was given a seat on the board of a Ukrainian energy company, Burisma, which reportedly paid him more than $80,000 a month despite his not having any experience in the energy sector. 

Congressional investigators have also shown Hunter and other Biden family members receiving millions of dollars from a Chinese business entity with ties to the Chinese Communist Party.

Mr. Biden fils has vociferously denied bringing his father into his business affairs, telling Amy Robach, then of ABC News, in 2019: “I gave a hook to some very unethical people to act in illegal ways to try to do some harm to my father. That’s where I made the mistake. … So I take full responsibility for that. Did I do anything improper? No, not in any way. Not in any way whatsoever.”

But the newly released WhatsApp messages show that the younger Mr. Biden explicitly invoked his father’s presence, and name, when he demanded money from the Chinese associate. 

“I am sitting here with my father and would like to understand why the commitment made has not been fulfilled,” he wrote in the July 2017 message to his business partner, Henry Zhao. The younger Mr. Biden added that he would “make certain that between the man sitting next to me and every person he knows and my ability to forever hold a grudge that you will regret not following my direction.”

At the time Mr. Biden wrote the message, his father had left the vice presidency and was making money through speaking engagements around the world.

Throughout the 2020 campaign and during his time in the White House, the elder Mr. Biden has said he had no knowledge of the financial dealings of his son, who he says he is “proud of” after his long battle with addiction and current reported sobriety. 

“I have never discussed with my son or my brother or anyone else anything having to do with their businesses, period,” Mr. Biden told reporters at a 2019 event in South Carolina as he competed for the Democratic nomination. One month later, he reiterated that he had no knowledge of his son’s business affairs. “I have never spoken with about his overseas businesses,” he told reporters. 

The White House press office has also been vigorously denying the allegations that the president was involved in helping the first son make money off the Biden family name. During a press briefing on Friday, one day after the encrypted text message was released by the House Ways and Means Committee, the White House press secretary, Karine Jean-Pierre, declined to comment on the story. 

“This is not a conversation that I’ve had with the president,” she said when asked if Mr. Biden was sitting next to his son when that 2017 message was sent. Like with all press queries about investigations into the Biden family, she referred the question to the White House counsel’s office, which has been handling issues related to the younger Mr. Biden. 

When asked in a follow-up question if she would speak with the president about the matter after the briefing, Ms. Jean-Pierre responded, “No.”

Conservative lawmakers are now accusing the president of not being truthful in the wake of the release of the text messages. “I’ve repeatedly said if the allegations are false, Joe Biden could clear this up by being transparent and sharing the truth with the American people,” Senator Cruz said on Monday, adding that the White House is trying to “stonewall.”

The president is not the only person accused of lying to the public about his son’s business endeavors. Following the disclosure of a whistleblower allegation that the United States attorney for Delaware, David Weiss, was hampered by the Department of Justice in his investigation into the first son, members of Congress are calling for Attorney General Garland’s impeachment. 

Mr. Garland denied interference with Mr. Weiss’s office following the whistleblower disclosure, which led some to accuse him of being dishonest. “What he is saying and what David Weiss is saying are two different things,” Speaker McCarthy told Fox News on Monday. “If it comes true what the IRS whistleblower is saying, we’re going to start impeachment inquiries on the attorney general.”

The first son is also preparing for what will likely be a high-profile civil suit at his home state of Delaware. The lawsuit, filed against Mr. Biden by a computer repair shop owner, John Pail Mac Isaac, alleges that the first son defamed the repairman’s character after a number of embarrassing documents, photos, and videos were leaked by the thousands from his laptop to the public. 

Throughout the process of denying the laptop was his, Mr. Biden defamed Mr. Mac Isaac by calling him a liar, the lawsuit alleges. The authenticity of the laptop was confirmed by a number of outlets, including the Washington Post and CBS News. 

Mr. Mac Isaac is seeking $1.5 million from the president’s son for defamation. His lawsuit points to the contractual agreement made between the two parties that stipulates that “equipment left with the Mac Shop after 90 days of notification of completed service will be treated as abandoned and you agree to hold the Mac Shop harmless for any damage or loss of property.”

Mr. Biden, in turn, is countersuing Mr. Mac Isaac for so-called invasion of privacy, claiming that he had no right to view, copy, or distribute materials from the computer. Mr. Mac Isaac’s legal team argues that the phrase “loss of property” in their contract includes the disclosure of data from the laptop.