Hillary Clinton. Thomson Reuters The Hillary Clinton campaign pinned blame on FBI Director James Comey for its stunning election night loss to Donald Trump.

Navin Nayak, the director of opinion research on the campaign, sent an email to senior staff Thursday evening outlining what the campaign believed were the reasons for its loss. The email, which was first reported by Politico, was confirmed to Business Insider by a Clinton campaign staffer.

Nayak signaled in the email that the campaign believes two bombshells from Comey in the final days of the election helped swing the electorate toward Trump — an initial Comey letter to Congress that reactivated an investigation into Clinton's private email server, and a subsequent letter last Sunday that again cleared her of wrongdoing.

"We believe that we lost this election in the last week. Comey's letter in the last 11 days of the election both helped depress our turnout and also drove away some of our critical support among college-educated white voters — particularly in the suburbs," Nayak wrote. "We also think Comey's 2nd letter, which was intended to absolve Sec. Clinton, actually helped to bolster Trump's turnout."

The campaign said Comey's first letter likely helped depress turnout among Clinton's supporters. That served as a shift in thinking, or at least posture, from last week, when the campaign's communications director argued that the reactivated FBI investigation had actually helped excite Clinton's base.

But Nayak wrote that after seeing record early-vote turnout in several states, turnout lagged on Election Day in swing-state metropolitan areas like Philadelphia, Detroit, Milwaukee, and Raleigh-Durham.

Comey's second letter "energized Trump supporters," Nayak wrote.

"There is no question that a week from Election Day, Sec. Clinton was poised for a historic win," Nayak wrote. "In the end, late breaking developments in the race proved one hurdle too many for us to overcome."

Additionally, Nayak pointed to anger at global institutions, a desire for change after a two-term Democratic president, the challenges of reassembling President Barack Obama's voting coalition, and the "unprecedented task" of electing the nation's first female president as hurdles to the campaign's success.

Nayak also suggested some blame lay at the feet of Green Party nominee Jill Stein, whose 130,000 votes in three key swing states were "an important reminder of the influence of 3rd party votes."