How it all came to light
On May 30, three weeks after Winner allegedly printed the classified document,
The Intercept (Glenn Greenwald's current mode) contacted the U.S. government, likely through the NSA, to discuss an upcoming story based on the intelligence document it had obtained. The Intercept even shared a copy of the document with government officials, who confirmed that it was indeed classified at the top secret level, "indicating that its unauthorized disclosure could reasonably result in exceptionally grave damage to the national security," the affidavit said.
Two days later, the FBI was notified of the matter and initiated an investigation to determine the source of the leak.
Further analysis of the documents showed that they "appeared to be folded and/or creased, suggesting they had been printed and hand-carried out of a secure space," according to the affidavit.
Winner was one of just six individuals who had printed the intelligence document, according to an internal audit of the agency that housed the report. The audit also revealed that Winner was the only individual of the group that had email contact with the news outlet.
FBI agent Justin Garrick said in the affidavit filed with the court that he interviewed Winner at her home on Saturday and that she "admitted intentionally identifying and printing the classified intelligence reporting at issue" and sent it to a news outlet.
The news outlet was not identified in the charging documents, but a source with knowledge of the matter confirmed that the charges were connected to The Intercept’s Monday report titled: "Top-Secret NSA report details Russian hacking effort days before 2016 election."
http://abcnews.go.com/US/leaking-secret-nsa-report-russia-unfolded/story?id=47858751