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Hillary Clinton's former campaign manager said President Trump's abrupt firing of FBI Director James Comey on Tuesday "terrifies" him.

"Twilight zone," Robby Mook tweeted. "I was as disappointed and frustrated as anyone at how the email investigation was handled. But this terrifies me." During the 2016 presidential campaign, the FBI started an investigation into how Clinton handled classified emails on a private server during her time as secretary of state. Comey announced in July 2016 that while Clinton was "extremely careless" in how she handled her email system, no charges would be filed. Days before the election, Comey told Congress the FBI was looking at emails found during an investigation of Anthony Weiner, husband of Clinton aide Huma Abedin, that might have something to do with the Clinton probe, but on Nov. 6, he told Congress the FBI was sticking to its original conclusion.

On Tuesday, the FBI had to send the Senate Judiciary Committee a letter clarifying something Comey said during a hearing last week; he testified that Abedin forwarded "hundreds and thousands" of emails to Weiner, but the FBI said in its letter they found that only "two email chains containing classified information were manually forwarded" to him.