Hillary Clinton met with the FBI for three and a half hours Saturday as part of the investigation into her use of a private email server while leading the State Department, her campaign said.

The investigation has cast a shadow over her campaign, and news of FBI agents interviewing the former secretary of state could heighten anxiety among Democrats that their nominee might be indicted before November. It also has put the Justice Department in the position of having a major say in how the 2016 vote turns out and serves as a reminder of Clinton’s negatives to voters already skeptical of her trustworthiness.

“Secretary Clinton gave a voluntary interview this morning about her email arrangements while she was secretary,” Clinton spokesman Nick Merrill said in a statement. “She is pleased to have had the opportunity to assist the Department of Justice in bringing this review to a conclusion. Out of respect for the investigative process, she will not comment further on her interview.”

An aide said the interview occurred at FBI headquarters in Washington Saturday morning. The FBI declined to comment on the interview.

The meeting means the investigation into Clinton’s use of a private email server for official business as secretary of state is coming to an end. The question now becomes how long it will take for the FBI to conclude its probe.

Sources familiar with the investigation had previously told CNN the Justice Department’s aim was to wrap up before the Republican and Democratic conventions later this month. The timing is crucial, because if Clinton were to be indicted before the convention, Democrats could perhaps nominate another candidate.

In May, CNN reported that multiple law enforcement officials said investigators hadn’t yet found sufficient evidence to bring charges, and that they were not expected to be brought against Clinton. The FBI and Justice Department are working in tandem on the investigation and jointly will present the results of the probe to higher level officials, including Attorney General Loretta Lynch, Assistant Attorney General John Carlin and Deputy Attorney General Sally Yates.

Presumptive Republican nominee Donald Trump said it was “impossible for the FBI not to recommend criminal charges against Hillary Clinton.”

“It is impossible for the FBI not to recommend criminal charges against Hillary Clinton. What she did was wrong! What Bill did was stupid!” Trump tweeted, referring to the former president’s meeting with Lynch earlier this week that has raised questions about the Justice Department’s impartiality in the matter.

Asked by CNN’s Brianna Keilar in a “State of the Union” interview Saturday about the possibility of the presumptive Democratic nominee being indicted, New Jersey senator — and potential Clinton running mate — Cory Booker flatly ruled out the possibility.

“That’s just not going to happen,” said Booker, who declined to answer whether the former secretary of state should step aside in favor of Vermont Sen. Bernie Sanders or Vice President Joe Biden if she’s indicted before the election.

“That’s something that, to me, is not even within the realm of possibility,” Booker said.

A reminder of Clinton’s trustworthiness issues

The interview comes at the end of a week that could have been another win for Clinton as Trump continues to struggle, but instead demonstrated her — and her husband’s — inability to avoid unforced errors and leave past controversies behind.

House Benghazi Committee Republicans on Tuesday released their report on the September 11, 2012, attack where four Americans died, which drew significant media attention but lacked significant new information that changed the dynamic of the race. The panel’s biggest discovery was finding the email address and server over a year ago.

Clinton has maintained that no emails marked as classified at the time were sent on the server, and that information in some emails was retroactively classified. And her campaign has actively portrayed the congressional investigation into Benghazi as a partisan exercise, highlighted by last October’s 11-hour hearing where Clinton testified.

But the FBI interview, along with news that Bill Clinton and Lynch met at an Arizona airport Monday, shows Clinton can’t move past the email issue — a story that overshadowed the launch of her campaign in early 2015 and helped Bernie Sanders find running room.

Sanders, in fact, is still in the race, pushing for progressive changes to the Democratic platform. As recently as Thursday, the Vermont senator said he’s not ready to endorse Clinton.

For Republicans, the possibility of an indictment is a satisfying one. The GOP has pursued the Clintons for 25 years, from the scandals of Bill Clinton’s presidency and his impeachment to Hillary Clinton’s actions leading up to and during the Benghazi attacks. That the FBI could hamstring her presidential ambitions is a bonus for the GOP.

Republicans pounce

Republican National Committee Chairman Reince Priebus said in a statement that Clinton is now “the first major party presidential candidate to be interviewed by the FBI as part of a criminal investigation surrounding her reckless conduct.”

“That the FBI wanted her for questioning reinforces her central role in deliberately creating a culture which put her own political ambitions above State Department rules and jeopardized our national security. In over 2,000 emails, Clinton’s decision exposed classified information, including 22 that included top secret intelligence, just so she could skirt transparency laws in order to hide her shady dealings as secretary of state,” Priebus continued.

He added, “The American people need to have confidence that the Obama Justice Department is conducting a fair and impartial investigation, but when the attorney general meets secretly with Bill Clinton just days before Hillary’s interrogation is conducted discreetly over a holiday weekend, it raises serious concerns about special treatment.”

RNC chief strategist and communications director Sean Spicer also pounced on the news Saturday afternoon.

“.@HillaryClinton campaign statement says She “voluntarily” met w @FBI for 3.5 hours this morning – yeah, lots of people volunteer 2 do that,” he tweeted.

He quickly added, “Now I get it! After Attorney General @LorettaLynch & @billclinton secretly meet @HillaryClinton spends 3.5 hrs #FourthOfJulyWeekend @fbi HQ”

But the interview is a reminder for Republicans that Trump is a major liability himself. He’s more unpopular than Clinton is and his poll numbers are sliding. Her campaign and allies have been airing millions of dollars’ worth of ads against him, many highlighting his impolitic statements about women and minorities — two groups that are backing Clinton by large margins.

The GOP establishment has yet to fully rally around the billionaire New York businessman, who trails Clinton 46% to 40% in the latest CNN Poll of Polls and has struggled to raise money in comparison to the Clinton and Democratic juggernaut.

Server revelations prompted lawsuits

The revelations of the email server as part of the House’s Benghazi probe have also resulted in lawsuits filed in Freedom of Information Act cases by the conservative Judicial Watch and other groups.

One such lawsuit saw Clinton’s top aide, Huma Abedin, deposed this week, along with other State Department staffers.

A State Department Inspector General report released in late May said Clinton failed to follow rules or inform key staff about the server.

“At a minimum, Secretary Clinton should have surrendered all emails dealing with Department business before leaving government service and, because she did not do so, she did not comply with the Department’s policies that were implemented in accordance with the Federal Records Act,” the report said.

She won’t be able to frame the FBI investigation, run by President Barack Obama’s Justice Department, as partisan against her. And this week’s seemingly impromptu meeting between Lynch and Bill Clinton was another problem for Hillary Clinton’s campaign.

The meeting happened as Lynch’s plane sat Monday on the tarmac of Phoenix Sky Harbor International Airport after Clinton attended a fundraiser for his wife’s campaign in the Phoenix area, a campaign source tells CNN’s Brianna Keilar.

John Gomez, deputy chief of staff to Maricopa County Supervisor Steve Gallardo, confirmed that he and 13 other Latino leaders in the community met with Bill Clinton Monday afternoon.

The resulting backlash led Lynch on Friday to publicly declare she would accept the determinations and findings of DOJ career prosecutors and the FBI.

“I certainly wouldn’t do it again because I think it has cast this shadow over what it should not, over what it will not touch,” Lynch said in Aspen, Colorado. “It’s important to make it clear that that meeting with President Clinton does not have a bearing on how this matter will be reviewed and resolved.”