1. Why was Comey fired?

May 9 “I cannot defend the director’s handling” of the Clinton email investigation. Rod J. Rosenstein May 11 Comey’s “a showboat, he’s a grandstander, the F.B.I. has been in turmoil.” President Trump

White House officials said the decision was based on a recommendation by Rod J. Rosenstein, the deputy attorney general, who wrote a memo raising concerns about Mr. Comey’s handling of the Hillary Clinton email investigation. But days later, President Trump went further, criticizing Mr. Comey as a “showboat” — apparently referencing a Senate testimony the week before that reportedly left the president fuming.

2. Who wanted the memo?

May 9 “No one from the White House. That was a D.O.J. decision.” Sean Spicer May 10 Trump asked for “their recommendation in writing.” Sarah Huckabee Sanders

On May 9, the day of the firing, White House press secretary Sean Spicer said that the Department of Justice drafted the memo without any influence from the White House. By the next day, the deputy press secretary, Sarah Huckabee Sanders, said that Mr. Trump had requested the memo based on what the officials told him in the meeting.

3. When was the decision made?

May 9 Rosenstein “made a determination” and Trump followed it. Sean Spicer May 11 Trump “had already made that decision” before Rosenstein. Sarah Huckabee Sanders

A White House official said President Trump had been dissatisfied with Mr. Comey for months. But the precise moment when he decided to fire him has shifted. Mr. Spicer first said the president responded to Mr. Rosenstein’s memo, which came after a meeting on May 8. Ms. Sanders said the president decided before that meeting took place.

4. Was the Russia investigation a factor?

May 9 “This has nothing to do with Russia.” Kellyanne Conway May 11 “When I decided to just do it, I said to myself” that “Trump and Russia is a made-up story.” President Trump

Mixed up with the controversy over Mr. Comey’s ouster is a continuing F.B.I. investigation into ties between Russia and the Trump campaign. While President Trump’s surrogates, including the White House counselor Kellyanne Conway, indicated the firing was unrelated, he said days later that the investigation was on his mind when he decided to fire Mr. Comey.

The next week, the Times reported that according to an American official, Mr. Trump told Russian officials visiting the White House that Mr. Comey was “a real nut job” and that he “faced great pressure because of Russia,” but that it had been relieved.

5. Had Comey lost support from the F.B.I. rank and file?

May 10 “The rank and file of the F.B.I. had lost confidence.” Sarah Huckabee Sanders May 11 Comey has “broad support” and “still does to this day.” Andrew G. McCabe

An early justification for firing Mr. Comey was the loss of confidence he faced among rank-and-file members of the F.B.I., a claim Ms. Sanders repeated on May 11. But during a hearing before the Senate Intelligence Committee, held later that same day, the agency’s acting director, Andrew G. McCabe, said that Mr. Comey was held in high regard.

On May 12, Mr. Trump and Mr. Spicer each gave explanations for recent contradictions. The president said on Twitter, “As a very active President with lots of things happening, it is not possible for my surrogates to stand at podium with perfect accuracy!”