The Post’s Matt Zapotosky breaks down the unknowns following the FBI’s announcement on Oct. 28 that it will renew its Hillary Clinton email probe. (Bastien Inzaurralde/The Washington Post)

The FBI has obtained a warrant to search the emails found on a computer used by former congressman Anthony Weiner that may contain evidence relevant to the investigation into Hillary Clinton’s private email server, according to law enforcement officials.

One official said the total number of emails recovered in the investigation into Weiner (D-N.Y.) is close to 650,000, but that reflects many emails that are not related to the Clinton investigation. But officials familiar with the case said that the messages include a significant amount of correspondence associated with Clinton and her top aide, Huma Abedin, Weiner’s estranged wife.

FBI agents investigating Clinton’s use of a private email server while secretary of state knew early this month that messages recovered in a separate probe might be germane to their case, but they waited weeks before briefing the FBI director, according to people familiar with the case.

The director, James B. Comey, has written that he was informed of the development Thursday, and he sent a letter to legislators the next day letting them know that he thought the team should take “appropriate investigative steps designed to allow investigators to review these emails.”

That missive ignited a political firestorm less than two weeks before the election. Almost instantly, Comey came under intense criticism for his timing and for bucking the Justice Department’s guidance not to tell Congress about the development. And his announcement means that Clinton could have to contend with the news that the FBI has resumed its investigation of her use of a private email server — without any clarity on whether its investigators will find anything significant — up to and beyond Election Day.

People familiar with the case said that agents on the Clinton email team had known about the messages since soon after New York FBI agents seized a computer related to their investigation into Weiner, who has been accused of exchanging explicit messages with a 15-year-old girl.

Officials said the agents probing Clinton’s private email server did not tell the director immediately because they were trying to better assess what they had.

“It’s a step-by-step process,” said one senior law enforcement official. “There are many steps along the way that get you to a place where the director can be appropriately briefed in order to make a decision” about whether to move forward.

Investigators will now look at whether the newly uncovered emails contain classified information or other evidence that could help advance the Clinton email probe. It is possible, though, that the messages could be duplicative of others already recovered elsewhere or that they could be a collection of benign, personal notes.

Several law enforcement officials with technical expertise said it is generally not difficult to create software to analyze such emails, searching for terms like “secret” or “top-secret” or any mention of places with classified operations, such as Pakistan. Agents should also be able to figure out quickly how many of the emails duplicate those that have already turned up.

“You could automate that pretty quickly,” said one law enforcement official.

What will take more time, however, is making conclusions about whether any of the emails include classified information. That process, former FBI officials have said, could be cumbersome and drag on after the election. Investigators would have to read those for potentially relevant information, and, if there were questions about their classification, send them to other agencies for review.

But no one involved in the investigation is trying to delay, officials say. “This is not a team that sits on its hands,” said one official.

Abedin has told people that she is unsure how her emails could have ended up on a device she viewed as belonging to her husband, according to a person familiar with the investigation and civil litigation over the matter.

An announcement from the FBI in early October, when the emails were discovered, might have been less politically damaging for Clinton than one coming less than two weeks before the Nov. 8 election. The FBI declined to comment.

Comey wrote in his letter to Congress, “We don’t know the significance of this newly discovered collection of emails,” and federal law enforcement officials have said that investigators on the Clinton email team still had yet to thoroughly review them.

Comey in July announced that he was recommending that the investigation into Clinton’s use of a private email server while she was secretary of state be closed without charges. But he said investigators had found classified information on the server and characterized Clinton’s and her aides’ conduct as “extremely careless.”

Legislators on both sides of the political aisle are likely to raise questions about why the team investigating Clinton’s private email took so long to brief Comey. Clinton and her backers have pushed aggressively for the bureau to release more information about its findings and criticized the agency for making its work public without knowing more. Republican presidential nominee Donald Trump has called the matter “the biggest scandal since Watergate” and suggested, without evidence to support it, that the case against Clinton was now “so overwhelming.”

A Washington Post-ABC News tracking poll found that more than 6 in 10 likely voters said the FBI’s announcement would make no difference in their vote. A little more than 3 in 10 said the news made them less likely to support Clinton, though about two-thirds of those were Republicans or Republican-leaning independents.