Days before Americans went to the polls, the FBI made the decision to reopen its examination of Hillary Clinton's email accounts. This move is what she is attributing her devastating defeat to.
During a phone call with senior campaign donors, Clinton said she was winning until FBI director James Comey sent a letter to Congress announcing that the FBI had uncovered emails possibly related to its earlier probe into her use of a private server as secretary of state.
The new examination was sparked by an unrelated investigation into former New York politician Anthony Weiner, the estranged husband of one of her senior aides.
The surprise announcement by the FBI on October 28 came after three debates in which Republican Donald Trump was widely criticised for his performance.
Clinton said that her campaign was leading by large margins in nearly every battleground state and was tied in Arizona (a traditionally Republican stronghold) until Comey released the letter.
Trump's campaign jumped on the FBI's decision and used it against Clinton, even though it was unclear whether her correspondence was tied up in the probe.
Comey told politicians on the Sunday before the election that the bureau had found no evidence to warrant criminal charges. His "all clear" message only served to further motivate Trump supporters, Clinton told donors on the call.
In the nine days between Comey's initial statement and his "all clear" announcement, nearly 24 million people cast early ballots. That was roughly 18% of the expected total votes for president.
Donors who listened to the call said that while Clinton accepted some blame for her loss, she made little mention of the other factors driving Trump's victory.