WASHINGTON - United States President Donald Trump stunned Washington on Tuesday (May 9) with his shock firing of FBI Director James Comey, who was leading an investigation into whether Trump's aides colluded with Russia to sway last year's US election.
The White House has said that Trump acted on the recommendations of both Deputy Attorney General Rod Rosenstein and Attorney General Jeff Sessions, citing the FBI's handling of the email scandal involving then-Democratic presidential nominee Hillary Clinton.
Here are some key questions that have been raised as a result of the move.
WAS THERE ANOTHER POLITICAL MOTIVE?
The move to dismiss Comey over the Clinton email probe has sparked a backlash from some Democrats in Congress who say the decision had the appearance of a cover-up. Some Republicans have also found the timing of the move troubling.
Comey had already been under fire from both quarters for his handling of the probe into Clinton's unauthorised use of a private email server during the time she was a secretary of state for President Barack Obama.
Comey said last July the Clinton email case should be closed without prosecution, but just 11 days before the Nov 8 election, he declared that he had reopened the investigation because of a discovery of a new trove of Clinton-related emails.
A few days later, the FBI said the new emails did not change its July decision not to recommend criminal charges against Clinton but many Democrats believe the move had been a major factor in Clinton's election defeat.
Last Wednesday, Comey told a hearing of the Senate Judiciary Committee that he had no regrets about his decisions on the matter, but said he felt "mildly nauseous" that his actions might have tipped the election to Trump.
He said he was faced with either concealing the investigation until after the vote or to inform Congress. "To not speak about it would require an act of concealment in my view. Concealing, in my view, would be catastrophic."
One reason the Clinton explanation isn't going down well is because the facts of the FBI inquiry were well-known at the time Trump took office and asked Comey to stay on the job.
Trump had also once praised Comey for his "guts" in his pursuit of Clinton during the campaign.
White House officials have so far denied allegations that there was any political motive in the move by Trump.
But the big question remains why now, and Trump's administration will have to build a strong case to answer that question.
WHAT HAPPENS TO THE FBI INVESTIGATION INTO RUSSIA'S INTERFERENCE IN THE US ELECTION?
Under Comey's leadership, the FBI concluded that President Vladimir Putin approved a multi-faceted campaign to tilt the vote in Trump's favour.
But Russia has repeatedly denied any meddling in the election and the Trump administration denies allegations of collusion with Russia.
Democrats - already angry that Congressional inquiries into the Russian meddling have been hamstrung by Republicans' willingness to defend Trump - have voiced sharp concerns that the FBI's investigation may now be in jeopardy too.
Senator Chuck Schumer of New York, the Democratic leader, said unless the administration appoints an independent special prosecutor to probe the Russian meddling, "every American will rightly suspect that the decision to fire director Comey was part of a cover-up".
In the wake of Tuesday's stunning moves, the president, the attorney general or the deputy attorney general will be called on to reassure the public that the investigation will continue as aggressively as it would have without a change in leadership at the bureau.
Trump will also be under pressure to yield to calls for a special prosecutor to take over the case, a decision that might create greater confidence in the independence of the investigation but that the president and his allies might see as a potentially more perilous course.
Meanwhile, legal experts Reuters spoke to have also said Trump's dismissal of Comey does not mean the FBI's investigation will be disrupted or that it would end. They say career FBI staffers can continue the probe even as the search for a new FBI director begins.
WHAT IS ATTORNEY GENERAL JEFF SESSIONS' ROLE IN THE FIRING?
The firing has also raised questions about the role of A-G Sessions, a former senator from Alabama and one of Trump's earliest supporters.
Sessions had recused himself from the Russia investigation in March, after it was revealed that he had provided inaccurate information to Congress about his meetings with the Russian ambassador to the US, Sergey Kislyak.
The investigation is now overseen by his deputy, Rosenstein - the man who authored the three-page rationale for removing Comey from the bureau because of his handling of the Clinton email investigation.
On Tuesday, however, he wrote a letter to Trump endorsing Rosenstein's memo and making the case for Comey's immediate ouster. In that letter, Sessions did not describe his specific concerns but said, "A fresh start is needed at the leadership of the FBI."
Speaking to the New York Times, Clinton's campaign chairman John Podesta made note of Sessions' recusal. "The attorney general who said he recused himself on all the Russia matters recommended the firing of the FBI director in charge of investigating the Russia matters," he said. "Now more than ever, it's time for an independent investigation."
SOURCES: NYTIMES, REUTERS, AGENCE FRANCE-PRESSE, BLOOMBERG