The deputy attorney general just threw more cold water on the White House's explanation for Comey's firing

Deputy Attorney General Rod Rosenstein told senators during a closed-door briefing Thursday that he knew FBI Director James Comey was going to be fired before he wrote a memo outlining Comey's mishandling of the investigation into Hillary Clinton's use of a private email server, a top Democratic senator said.

Sen. Claire McCaskill of Missouri told reporters gathered outside of the briefing room that Rosenstein had "acknowledged that he learned Comey would be removed prior to him writing his memo," despite the White House's initial insistence that Trump fired Comey at Rosenstein's recommendation.

Trump fired Comey on May 9. Democratic Sen. Dick Durbin told reporters that Rosenstein "knew the day before" Comey was fired that Trump intended to dismiss him.

But White House press secretary Sean Spicer told reporters shortly after Comey was fired that the decision "was all" Rosenstein.

"This was a DOJ decision," Spicer said, referring to the Department of Justice. White House deputy press secretary Sarah Huckabee Sanders told reporters the next day that the letters Trump received on Tuesday outlining "the basic atrocities" Comey committed "in circumventing the chain of command of the Department of Justice" persuaded him to fire the director.

Vice President Mike Pence, the day after Comey's firing, also said Trump had based his decision on Rosenstein's recommendation.

That explanation quickly unraveled, however, as reports surfaced that Trump had already made his decision to fire Comey nearly a week before Rosenstein wrote the memo.

In an interview with NBC's Lester Holt last Thursday, Trump acknowledged that he was going to fire Comey "regardless" of the recommendations given to him by Rod Rosenstein and Attorney General Jeff Sessions. He called Comey "a showboat" and "a grandstander" and said he fired the director because the FBI was in "turmoil." (Acting Director Andrew McCabe denied Thursday that the bureau had lost faith in Comey before he was fired.)

Rosenstein reportedly threatened to resign - after only two weeks on the job - because he was made out to be the administration's scapegoat. The Justice Department on Thursday denied that Rosenstein had made the threat, but the White House ultimately shifted the responsibility off Rosenstein.

"After watching Director Comey's testimony last Wednesday, the president was strongly inclined to remove him," the White House said on Thursday, as part of a "timeline" of the president's decision-making process.