David Weiss, the federal attorney who investigated and prosecuted Hunter Biden, quietly resigned in January, NBC News has learned.

A spokesperson for the U.S. Attorney’s Office in Delaware and a spokesperson for the Justice Department confirmed that Weiss stepped down as both U.S. attorney and special counsel on Jan. 17 — three days before President Donald Trump began his second term.

No statement or announcement was made at the time, and a copy of Weiss’ resignation letter has not been made public. By comparison, former special counsel Jack Smith’s resignation was included in a court filing shortly before Trump’s inauguration.

Two sources familiar with the matter told NBC News that Weiss submitted his resignation voluntarily — he was not asked to resign, the sources said.

Weiss did not respond to a request for comment Friday night.

He was succeeded by acting U.S. Attorney Shannon T. Hanson. Hanson previously worked for Weiss in the US Attorney’s office.

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It was expected that Weiss would step down at some point after he concluded his investigation and issued his final report on Biden. That report was made public Jan. 13.

In it, he bashed President Joe Biden for pardoning his son Hunter.

In the official White House statement announcing the pardon, the president described the prosecution of his son as a “miscarriage of justice” which prosecutors for the special counsel later disputed in a court filing.

Biden repeatedly said during the 2024 presidential campaign, including after he dropped out, that he would not pardon his son.

The cases brought by Weiss led to a guilty verdict on gun-related charges in Delaware and a guilty plea on tax and fraud charges in California. Biden was scheduled to be sentenced in December 2024 for both cases.

As NBC previously reported, Weiss pointedly responded to critical statements by President Biden about the investigation following the December pardon.

Weiss wrote in his final report that the president could not “rewrite history,” suggesting that Biden’s criticism of the case against his son when he announced his pardon decision had maligned “the public servants at the Department of Justice based solely on false accusations.”

“Politicians who attack the decisions of career prosecutors as politically motivated when they disagree with the outcome of a case undermine the public’s confidence in our criminal justice system,” Weiss wrote. “The President’s statements unfairly impugn the integrity not only of Department of Justice personnel, but all of the public servants making these difficult decisions in good faith.”