Legal experts said Congress and the executive branch — mainly the Justice Department — were likely to have vastly different views about whether the disclosure that the case in question involved Hunter Biden was legally problematic.
Congress, the experts said, has often taken the position that its oversight authority allows it to hear from whomever it wants about whatever it wants. On the other hand, the Justice Department was likely to see it as a potentially illegal disclosure about a continuing investigation. If Hunter Biden is indicted, the experts said, his lawyers could move to question the supervisor about whether he disclosed details about the investigation.
In a number of televised interviews, Mr. Lytle, the lawyer for the I.R.S. supervisor, declined to confirm that Hunter Biden was the subject of the investigation. Neither Mr. Lytle nor another lawyer representing the I.R.S. supervisor, Tristan Leavitt, responded to messages seeking comment about Mr. Clark’s assertions.
In a post on Twitter, Mr. Leavitt said, “Our client has an exemplary record and is making his disclosures to Congress the right way and for the right reasons.”
In any high-profile investigation, particularly those involving politically connected individuals, there are often disputes between agents, prosecutors, supervisors and senior Justice Department officials in Washington about how to conduct the inquiry and whether to bring charges.
I.R.S. and F.B.I. agents have complained for months that they have enough evidence to bring a case against Hunter Biden but that their superiors, who have to weigh factors like whether a less prominent person would be charged with a crime in the same circumstances, have yet to make decisions. Some tax lawyers at the Justice Department are said to be skeptical that there is enough evidence to bring a tax case.
Representative James R. Comer, Republican of Kentucky and the chairman of the House Oversight Committee, which has been pursuing an investigation into the Bidens’ business dealings, publicly said that the letter was about Hunter Biden, although Mr. Comer did not say how he knew that.