Last July, then-FBI chief James Comey took the unusual step of publicly announcing the end of the investigation into Hillary Clinton’s private email server — without telling his boss, then-Attorney General Loretta Lynch. According to a new report, he was motivated by a dubious Russian document.

Comey reportedly believed Lynch’s judgment might be compromised, thanks to the document, which appeared to show that Lynch had reassured a Clinton staffer that the investigation wouldn’t go too far. He reportedly thought the investigation would lose all credibility if that document were leaked.

But the document turned out to be bad Russian intelligence, the Washington Post reported Wednesday, and the FBI knew that only a month after Comey made his announcement. In fact, the document may even be a fake meant to confuse the bureau, officials familiar with its content told the Post.

The document reportedly describes an email sent from then-chair of the Democratic National Committee Debbie Wasserman Schultz to Leonardo Benado, who works for the George Soros-founded Open Society Foundations. According to the document, Wasserman Schultz suggested to Benado that Lynch had told Clinton campaign staffer Amanda Renteria that the email investigation wouldn’t dig too deep.

This document — combined with news of Lynch’s private meeting with Bill Clinton on a Phoenix tarmac — led Comey to make his fateful decision to end the investigation on his own. Months later, just days before the president election, Comey again took the initiative to announce on his own that the investigation into Hillary Clinton’s emails had been reopened. Clinton says that decision cost her the election.

But the FBI declined to investigate further, even after deciding the document was bad, and despite its potential election-shaping impact, according to the Post. Wasserman Schultz, Benado, and Renteria all said the FBI never interviewed them about it and contend that they don’t know one another.

“Wow, that’s kind of weird and out of left field,” Renteria told a Post reporter, the first person to tell her that the document even existed.

FBI agents reportedly informed Lynch of the document’s assertion, which she denied. She also offered to let the FBI formally interview her and her staff, which the FBI declined.

This isn’t the first time the existence of such a document has been alleged — the New York Times mentioned in April its role in shaping Comey’s decision to go public, but didn’t describe the document as Russian. The Times article also doesn’t mention officials’ doubts about the article’s veracity.