WASHINGTON — Out of hundreds of thousands of emails seized last month from disgraced former Rep Anthony D Weiner, a substantial number turned out to be copies of documents already reviewed by FBI agents and analysts, allowing the agency to wrap up in days a review that some had feared would take weeks, if not longer.

The FBI discovered approximately 650,000 emails on a computer that agents had seized while investigating Mr Weiner on allegations of sexual improprieties. Some of those emails belonged to Ms Huma Abedin, Mr Weiner’s estranged wife and a top aide to Mrs Hillary Clinton.

As it turned out, law enforcement officials said, there was no need to review all of the emails, only Ms Abedin’s. Those emails numbered in the thousands, and even many of those were duplicates of messages that had been looked at previously, officials said.

That allowed the FBI to sort through the emails faster than many, including some at the agency, had expected.

“You can’t review 650,000 emails in eight days,” Mr Donald Trump said at a rally on Sunday (Nov 6).

Maybe not, but they didn’t have to. Here’s how federal agents, in the span of a week, could pore over a huge cache of emails and once again conclude that neither Mrs Clinton nor her aides should face charges related to her handling of classified information on a personal server. The investigation, again, is closed.

HOW DID FBI AGENTS READ 650,000 EMAILS SO QUICKLY?

Taking to Twitter, Mr Michael T Flynn, a former Army lieutenant general and top Trump adviser, declared it “IMPOSSIBLE” that the FBI could have scanned 650,000 emails in eight days.

But that figure is misleading. When FBI agents seized Mr Weiner’s laptop, they did discover about 650,000 emails, but only some of them belonged to Ms Abedin, agents found. They realised that her emails might be relevant to the FBI’s completed investigation into Mrs Clinton’s use of a private email server, but those were only a small subset of the total.

SO HOW MANY EMAILS WERE REVIEWED?

The FBI has not said precisely, but officials have placed the number in the thousands.

READING THOUSANDS OF EMAILS IN EIGHT DAYS STILL SEEMS LIKE A LOT OF WORK

That number got even smaller relatively quickly. Many of the emails were copies of messages that agents had examined earlier while investigating Mrs Clinton and her aides. Again, it’s not clear how many were duplicates, but law enforcement officials say it was a substantial number. Filtering software can ferret out duplicates from far larger databases than Mr Weiner’s hard drive. That could have sped up the review, because the duplicates didn’t need to be examined again, but FBI employees would still have had to personally vet new emails.

WAS THERE CLASSIFIED INFORMATION ON THE COMPUTER?

It is not clear, but that was never the most pressing question. From the beginning, officials said it would take an extraordinary discovery to change their conclusion that nobody should face charges in the case. Prosecutors and agents knew that classified information had been improperly stored on Mrs Clinton’s server. The FBI director, Mr James B Comey, called it careless but said it did not rise to the level of a crime. Simply finding more classified information would not, by itself, have changed that conclusion.

The FBI has not said what was in the newly discovered emails, but records previously released under the Freedom of Information Act show that Ms Abedin’s inbox contained mostly scheduling discussions, routine office chatter and the occasional instruction from Clinton to print something.

WHY DIDN’T THE GOVERNMENT TELL US THIS WOULD ONLY TAKE A WEEK?

The FBI was reluctant to predict how long the review would take, repeatedly trying to lower the public’s expectation that it could finish before Election Day. Even though the number of emails seemed manageable early in the week, there was a chance that agents would discover something along the way that would require extensive follow-up.

Attorney General Loretta Lynch and Mr Comey assigned dozens of agents and analysts to the effort, including investigators who had originally worked on the case. Dozens worked around the clock for a week. Law enforcement officials said the review was completed Sunday morning.

WHAT NOW?

While the FBI investigation is closed, Republican members of Congress have said they will not stop looking into Mrs Clinton’s actions. Rep Jason Chaffetz of Utah, the chairman of the House Oversight and Government Reform Committee, has promised to investigate Mrs Clinton and said that inquiry could take years.

If Democrats win control of the Senate on Tuesday, they could open an inquiry of their own — into Mr Comey’s handling of the email investigation.

SO WHAT WAS THIS WHOLE WEEK ABOUT?

It depends on where you sit.

Mr Comey’s aides say it was about preserving the FBI’s credibility. Had word leaked out that the FBI was reading new emails that might be related to Mrs Clinton, they say, it would have raised suspicion that Mr Comey had not been forthcoming when he told Congress in July that the investigation was complete. Democrats and some former federal law enforcement officials say it was all about Mr Comey, who ignored long-standing guidelines and traditions and plunged the FBI into the presidential race. Had he followed standard Justice Department practices and kept quiet while the FBI did its work, they say, this all could have been avoided.

In the end, though, this was not much about Mrs Clinton at all. The FBI made its conclusion — careless, but not criminal — months ago, and nothing has changed.

WHAT DOES THIS MEAN FOR MR COMEY AND THE FBI?

Mr Comey has told aides that he feels no pressure to step down and has no plans to do so, with nearly seven years left in his term. Mrs Clinton’s surrogates say it would be politically difficult for her to fire him if she is elected. And the White House said Monday that President Barack Obama continued to have confidence in Mr Comey. But some FBI employees fear that the episode has damaged the bureau’s reputation of being nonpartisan and above the political fray. THE NEW YORK TIMES NEWS SERVICE