(WASHINGTON) -- Attorney General Merrick Garland on Tuesday gave his first public response to an IRS supervisor-turned-whistleblower who claimed to have information for Congress about potential mishandling of the yearslong federal investigation into President Joe Biden's son Hunter Biden.
Among the allegations laid out in a letter to lawmakers last month was that the whistleblower would contradict Garland's testimony on Capitol Hill that the Hunter Biden probe has remained free from any improper political interference, sources have told ABC News.
In an unrelated news conference Tuesday morning, Garland was asked whether he stood by those previous statements.
"Yes, it's still the case I stand by my testimony, and I refer you to the U.S. attorney for the District of Delaware who is in charge of this case and capable of making any decisions that he feels are appropriate," Garland said.
Federal authorities with the U.S. attorney's office in Delaware, led by U.S. Attorney David Weiss, a Trump appointee, have been investigating the younger Biden since 2018, ABC News previously reported.
Various news outlets have reported for months that prosecutors were nearing a conclusion, but no charges have yet been filed.
The investigation spilled into public view in December 2020, shortly after Joe Biden secured the presidency, when Hunter Biden confirmed the probe into his "tax affairs." Prosecutors have examined whether he paid adequate taxes on millions of dollars of his income, including money he made from multiple overseas business ventures.
Prosecutors have also explored allegations that Hunter Biden lied about his drug use on a gun application form in 2018, despite later acknowledging that he was addicted to drugs around that time.
ABC News previously reported the younger Biden borrowed $2 million from his lawyer and confidant Kevin Morris to pay the IRS for back taxes, penalties and liens that he owed.
The president's younger son said in an interview with CBS in 2021 that he was "fully cooperating, and I'm fully confident that at the end of the day it's all gonna be fine."
In April, in a letter to lawmakers obtained by ABC News, a lawyer for the IRS whistleblower said his client is an criminal supervisory special agent "who has been overseeing the ongoing and sensitive investigation of a high-profile, controversial subject since early 2020 and would like to make protected whistleblower disclosures to Congress."
The letter did not name Hunter Biden specifically, but lawmakers have been made aware he is the "high profile, controversial" subject that the lawyer is referring to. In addition, while the letter referred to preferential treatment that Hunter Biden allegedly received, there were no specific examples provided to support the accusations.
Leading Republicans, who have campaigned in part on promises of investigating the Biden family, seized on the whistleblower letter, reacting with alarm.
"It's deeply concerning that the Biden Administration may be obstructing justice by blocking efforts to charge Hunter Biden for tax violations," House Oversight Committee Chair James Comer said in a statement.
In response to the IRS agent's letter, Chris Clark, an attorney for Hunter Biden, said, "It appears this IRS agent has committed a crime" by disclosing information about his client.
"It is a felony for an IRS agent to improperly disclose information about an ongoing tax investigation," Clark said in a statement. "The IRS has incredible power, and abusing that power by targeting, embarrassing, or disclosing information about a private citizen's tax matters undermines Americans' faith in the federal government."
White House press secretary Karine Jean-Pierre declined to weigh in on the matter in April, stressing that the president was choosing to keep his distance: "I'll leave it to the Department of Justice to make their decision to move forward with this particular case. We're just not going to comment from here."
A spokesperson for the White House counsel insisted the administration had not gotten involved.
"President Biden has made clear that this matter would be handled independently by the Justice Department, under the leadership of a U.S. Attorney appointed by former President Trump, free from any political interference by the White House," Ian Sams said in an April statement. "He has upheld that commitment."
ABC News' Molly Nagle contributed to this report.