Story highlights She said the first letter from Comey stopped her momentum

She said the FBI development was too much to "overcome"

(CNN) Hillary Clinton told donors in a conference call Saturday that FBI Director James Comey delivered a double whammy to her candidacy in the final days of the campaign by taking another look at emails related to Clinton's private server before abruptly saying he found no wrongdoing.

A member of her national finance committee who was on the call told CNN that Clinton placed at least some of the blame on Comey for her stunning defeat to Donald Trump.

She said the first letter from Comey, sent to Congress on October 28, stopped the momentum she had built after three debates and the release of Trump's "Access Hollywood" tape.

She said the second letter, which came nine days later and exonerated Clinton, simply fired up Trump supporters and didn't put any on-the-fence voters who had been leaning her way at ease.

She said the FBI development was too much to "overcome," the donor on the call told CNN, but she acknowledged there were other headwinds facing her campaign that they didn't adequately combat.

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