Former CIA officer Abigail Spanberger, a Democrat challenging Rep. Dave Brat (R-Va.), had her unredacted personnel file released to GOP opposition researchers. The Postal Service, where she worked as an inspector prior to the CIA, said the release was the result of “human error.” (Julia Rendleman/For The Washington Post)

The U.S. Postal Service’s extraordinary release of sensitive personal information about an ex-CIA officer running for Congress resulted from an employee in a new position mishandling a public-information request, according to two congressional aides briefed on the matter.

Abigail Spanberger, a Democrat trying to unseat Rep. Dave Brat (R-Va.), touts her experience as a former intelligence officer and postal inspector. So on July 9, GOP opposition researchers with the super PAC America Rising filed a public records request with the federal government, seeking basic employment information.

The Postal Service told congressional aides in a briefing Thursday that the employee, who had not been properly trained, mistakenly treated the request as if Spanberger were asking for her own records.

In the space of 21 days — lightning speed by the snail-paced standards of Freedom of Information Request processing — the Postal Service handed over her Social Security number and medical history, along with employment history, part of a questionnaire known as a SF86 that Spanberger filled out years earlier as she sought security clearance.

“Please find enclosed the entire Official Personnel Folder (OPF) for Abigail Spanberger,” said a letter granting the FOIA request on July 30.

A total of four public-information requests were mishandled in this manner, the Postal Service said in a Thursday briefing of staff for Rep. Elijah E. Cummings (Md.), the top Democrat on the House Oversight and Government Reform Committee; Rep. Gerald E. Connolly (Va.), the top Democrat on the OGR government operations subcommittee, and the Senate Homeland Security Committee.

The Postal Service declined to provide any identifying information about the other three individuals whose information was mistakenly released, or to say if they are candidates for public office, according to two aides who were on the call. The aides spoke on the condition of anonymity because they were not authorized to publicly discuss the matter.

Postal spokesman David Partenheimer said he could not answer questions from The Washington Post about the errant employee or the other people whose information was released, citing an ongoing investigation into the matter.

The SF86 normally would not be released under FOIA, the aides said they were told on the call. In most cases, the Postal Service would share only past and present positions, salaries and locations of employment.

Postal officials said there are two categories of requests for employment history. One is when someone requests his or her own records or provides a waiver allowing a third party, such as a potential employer, to see them. Those are handled by the Postal Service’s human resources office.

The other category is a third-party request with no waivers, and that is handled by the Postal Service’s FOIA office.

The new employee was mistakenly treating all requests as if they belonged in the first category, the aides said they were told. Partenheimer declined to comment on that account.

After receiving the SF86, America Rising turned the material over to the Congressional Leadership Fund, a super PAC aligned with House Speaker Paul D. Ryan (R-Wis.), whose spokeswoman said the request was by no means out of the ordinary.

“It is standard operating procedure in American politics by both Democrats and Republicans to vet a candidate’s employment history, particularly when they have made it an issue on the campaign trail, as Abigail Spanberger has,” spokeswoman Courtney Alexander said.

Indeed, Spanberger’s team submitted a similar FOIA for her federal employment records, to see what information her political foes could turn up. A firm her campaign hired put in the request in December. She is still waiting for the documents.

Spanberger and Brat are running in Virginia’s 7th District, a longtime GOP stronghold in suburban Richmond where President Trump is unpopular. Cook Political Report classifies the race as “toss-up.”

Brat won the seat four years ago after beating then-House Majority Leader Eric Cantor in the GOP primary, a stunning upset fueled by an ascendant tea party. But this year, Brat must contend with a strong challenge from Spanberger, anti-Trump sentiment and lingering resentment from Cantor supporters.

Brat had declined to comment on the release of his rival’s records.

Amid the uproar over the incident from Democrats and more than 200 national security officials who served under presidents of both parties, some political candidates with past or present security clearances say they are now wondering: Does my opponent have my SF86?

“I don’t know if they have it,” said Elissa Slotkin, a former CIA analyst and Pentagon official who is running for Congress in Michigan’s 8th District as a Democrat. She expressed concern that Spanberger’s clearance form was released publicly.

“These are kind of techniques that we’re used to seeing from our adversaries,” she said. “Not from American political organizations.”

Greg Jaffe contributed to this report.