The Justice Department on Thursday released details about an investigation into nine discarded mailed-in ballots in Pennsylvania, an unusual step that stoked new fears that President Trump’s political appointees were using the levers of law enforcement to sow doubt about the election.
The U.S. attorney for central Pennsylvania, David J. Freed, announced in a statement that F.B.I. investigators were examining mail-in ballots from military members in Luzerne County in northeastern Pennsylvania that had been “discarded.” Seven of the nine ballots were cast for Mr. Trump, Mr. Freed said.
In a letter to the Luzerne County Bureau of Elections released on Thursday evening, Mr. Freed said investigators found that the nine ballots had been “improperly opened by your elections staff.” Under Pennsylvania election law, no ballots can be opened until Election Day, even for processing.
Mr. Freed added that the investigation found that “envelopes used for official overseas, military, absentee and mail-in ballot requests are so similar, that the staff believed that adhering to the protocol of preserving envelopes unopened would cause them to miss such ballot requests,” and had been opening envelopes.
Mr. Freed said he was taking the rare step of releasing details about the investigation because of “the limited amount of time before the general election and the vital public importance of these issues.”
A spokeswoman for the Justice Department did not respond to an email seeking comment. The Luzerne County district attorney said it had “consulted with the United States attorney’s office” after a county administrator notified them of “issues” with a ballot.
The announcement came as Mr. Trump refused to commit to accepting the results of the election and as voters around the country began casting ballots by mail and in early voting.
Election experts said the announcement was highly irregular. Justice Department policy calls for keeping voter fraud investigations under wraps to avoid affecting the election outcome, and the experts said it was almost unheard-of for the department to provide an update on the case and disclose the name of the candidate for whom the ballots had been cast.
“The question of who voters voted for would be immaterial in any kind of tampering investigation, and it seems to be in there for political reasons, to bolster the president’s arguments that the election is being rigged against him,” said Richard L. Hasen, a professor of law at the University of California, Irvine.
Justin Levitt, a former Justice Department official, said on Twitter that the investigation itself could be legitimate but denounced the disclosure of details about it, including the candidate’s identity.
The announcement itself was also unusual; Mr. Freed’s office deleted the news release from its website, positing a revised version. The original statement said all nine of the ballots had been cast for Mr. Trump, and the revised version said seven ballots were cast for the president and two remained in their envelopes.
Mr. Trump has made false claims about fraudulent voting a central message in his re-election campaign. The disclosure on Thursday provided the president and his allies with a new angle to attack mail-in voting: a conspiracy against his own voters.
Around the time Mr. Freed released the statement, the White House and Mr. Trump’s campaign cited the investigation in Pennsylvania as an example of the problems with mail-in voting.
“EVERY vote matters. 9 military votes MATTER,” Alyssa Farah, the White House communications director, said on Twitter. “Call me old fashioned: but I believe those willing to serve our nation in uniform especially deserve to have their vote counted accurately.”
Matt Wolking, the deputy communications director for the Trump campaign, wrote on Twitter, “Democrats are trying to steal the election.”
Attorney General William P. Barr has also been outspoken in his criticism of mail-in voting, repeating the president’s false claims that such ballots are rife with potential for fraud. He has also falsely stated that “there’s no secret ballot” in voting by mail. His criticisms, coupled with the rhetoric from Mr. Trump and his allies, have unnerved Democrats who fear that the Trump administration could seek to undermine or even disrupt the election in November.
The F.B.I. director, Christopher A. Wray, undercut that rhetoric on Thursday, telling lawmakers that the bureau had not uncovered a “coordinated national voter fraud effort.” He said that it would be a “major challenge for an adversary” to pull off a large-scale voter fraud operation that could affect election results.