The Department of Justice arrested Reality Leigh Winner, a 25-year-old intelligence contractor, accusing her of exposing a top-secret National Security Agency (NSA) document relating to Russian meddling in the U.S. elections that was apparently published by the Intercept on Monday.

The top secret document said Russian military intelligence conducted a cyber-attack on at least one supplier of voting software and sent phishing emails containing malicious software to more than 100 local election officials days before the ballots opened last year.

“Winner printed and improperly removed classified intelligence reporting, which contained classified national defense information from an intelligence community agency and unlawfully retained it,’’ court documents stated, adding that material was taken May 9 this year. “Approximately a few days later, Winner unlawfully transmitted by mail the intelligence reporting to an online news outlet.’’

When confronted, Winner admitted printing the report, despite not being credited with “needing-to-know” about its content, and said she was aware the information “could be used to the injury of the US and to the advantage of a foreign nation,” the affidavit says.

The Intercept reported that Russians tried to hack an election software company’s email system, targeting at least one employee there. The documents do not indicate if the Kremlin’s alleged efforts were successful.

The NSA document was marked to show that it would be eligible for declassification on May 5, 2042.

Intercept reporters told intelligence officials at the Office of the Director of National Intelligence and the NSA they were publishing the report with requests on what parts should be redacted in case it was damaging to national security.

Almost as soon as the Intercept contacted the agencies, federal authorities began tracing the leak. FBI special agent Justin Garrick reportedly investigated the creases in the NSA file, based on lines in the image the Intercept shared, offering a clue that the document had been folded and mailed. Investigators then checked printer logs, and ultimately found that Winner was one of six people who had printed the Russian election hacking report.

“Exceptional law enforcement efforts allowed us quickly to identify and arrest the defendant,” wrote Deputy Attorney General Rod Rosenstein in a statement. “Releasing classified material without authorization threatens our nation’s security and undermines public faith in government. People who are trusted with classified information and pledge to protect it must be held accountable when they violate that obligation.”