Justice Department's election crimes chief resigns after Barr allows prosecutors to investigate voter fraud claims

A Justice Department official says the agency is "looking into" allegations of ineligible voters in Nevada and mail-in ballots in Pennsylvania.

The head of the branch of the Justice Department that prosecutes election crimes stepped down from his post Monday in protest over a memo from Attorney General William Barr authorizing federal prosecutors to investigate "specific allegations" of voter fraud before the results of the presidential race are certified.

The official, Richard Pilger, who was director of the Election Crimes Branch of the Justice Department, said in an email to colleagues that he could no longer do his job in the wake of Barr's memo, which was issued as President Donald Trump's legal team mounts baseless legal challenges to the election results, alleging that widespread voter fraud cost him the race.

"Having familiarized myself with the new policy and its ramifications, and in accord with the best tradition of the John C. Keeney Award for Exceptional Integrity and Professionalism (my most cherished Departmental recognition), I must regretfully resign from my role as Director of the Election Crimes Branch," Pilger's letter said, according to a copy obtained by NBC News.

Pilger is remaining at the Justice Department in another capacity, officials said.

"I have enjoyed very much working with you for over a decade to aggressively and diligently enforce federal criminal election law, policy, and practice without partisan fear or favor," the letter said. "I thank you for your support in that effort."

Barr issued a memo Monday authorizing prosecutors "to pursue substantial allegations of voting and vote tabulation irregularities prior to the certification of elections."

That's a change of Justice Department policy, which had previously advised prosecutors that "overt investigative steps ordinarily should not be taken until the election in question has been concluded, its results certified, and all recounts and election contests concluded."

Barr, who has come under fire from right-wing media for not bolstering Trump's evidence-free claims of widespread voter fraud, declared the guidance outdated.

"Such a passive and delayed enforcement approach can result in situations in which election misconduct cannot realistically be rectified," Barr said in the memo.

A Justice Department official said the memo does not allege that there are substantial irregularities. It authorizes local U.S. attorneys to investigate if they learn of "clear and apparently-credible allegations of irregularities that, if true, could potentially impact the outcome of a federal election in an individual State."

It added: "While serious allegations should be handled with great care, specious, speculative, fanciful or far-fetched claims should not be a basis for initiating federal inquiries. Nothing here should be taken as an indication that the Department has concluded that voting irregularities have impacted the outcome of any election."

A Justice Department official said Tuesday that the department is "looking into" allegations of ineligible voters in Nevada and mail-in ballots in Pennsylvania.

NBC News and several other major news organizations projected Joe Biden as the winner of the presidential election Saturday after several states spent days counting ballots following a record turnout, including mail-in and absentee ballots. Trump has refused to concede, and one of his appointees in the General Services Administration has yet to sign paperwork to begin the presidential transition.

Barr was not asked or directed by Trump, any lawmaker or anyone in the White House to issue the memo, a senior Justice Department official said. Barr, however, met with Senate Majority Leader Mitch McConnell, R-Ky., earlier Monday. McConnell defended the president Monday on the Senate floor, arguing that he has a right to pursue recounts and lawsuits in court.

Barr did not respond to questions when he left McConnell's office, and a Justice Department spokesperson has declined to comment on what they discussed.

Julia Ainsley contributed.