Heading into the final week of the election, the Clinton campaign still faces questions about the ongoing email controversy.

The Federal Bureau of Investigation announced it will reopen the investigation into Hillary Clinton’s use of a private email server after learning of a new batch of emails pertinent to the investigation.

“In connection with an unrelated case, the FBI has learned of the existence of emails that appear to be pertinent,” FBI director James Comey said in a letter to congressional Republicans. He added that the Bureau will work to determine whether the emails in question contained any classified information.

As the political press focuses on the new investigation, it still remains unclear whether the continued investigation will put a damper on the momentum the Clinton campaign has built up throughout October.

US election 2016: the race for the White House in pictures Show all 12 1 /12 US election 2016: the race for the White House in pictures US election 2016: the race for the White House in pictures Republican U.S. presidential nominee Donald Trump shakes hands with Democratic U.S. presidential nominee Hillary Clinton at the conclusion of their first presidential debate at Hofstra University in Hempstead, New York Reuters US election 2016: the race for the White House in pictures President Barack Obama embraces Democratic nominee Hillary Clinton on stage at the party's convention in Philadelphia US election 2016: the race for the White House in pictures Donald Trump's wife Melania delivered a speech at the GOP convention in Cleveland that was later found to have been cribbed in part from Michelle Obama's 2008 convention address AP US election 2016: the race for the White House in pictures Hillary Clinton talks to reporters aboard her new campaign plane on Labour Day, 5 September, her first 'press conference' since 2015 (Getty Images) US election 2016: the race for the White House in pictures Donald Trump held a joint press conference with Mexican leader Enrique Pena Nieto in Mexico City in August, hours before reiterating his harsh immigration plans at a campaign rally in Arizona Reuters US election 2016: the race for the White House in pictures Bernie Sanders officially endorsed Hillary Clinton, saying his progressive vision for ‘a transformed America’ would be ’best served by the defeat of Donald Trump’ Reuters US election 2016: the race for the White House in pictures Khizr and Gazala Khan appeared at the DNC to slam Trump for his stance on Muslim immigration, citing the case of their son Humayun Khan, who was killed in combat while serving as a Captain in the US Army in Iraq US election 2016: the race for the White House in pictures Libertarian candidate Gary Johnson is doing better in polls than any third party candidate since Ross Perot, 20 years ago Nicholas Kamm/AFP/Getty US election 2016: the race for the White House in pictures Green Party candidate Jill Stein (centre) marches with supporters in Colorado AP US election 2016: the race for the White House in pictures Hillary Clinton and Virginia Senator Tim Kaine at a rally in Kaine's home state in July, days before Ms Clinton tapped him to be her running mate Getty US election 2016: the race for the White House in pictures Trump on the campaign trail with his vice presidential pick, Indiana governor Mike Pence AP US election 2016: the race for the White House in pictures Former Ukip leader Nigel Farage appears at a Trump rally in Mississippi in August, where he told the crowd that he 'wouldn't vote for Hillary Clinton if you paid me'.

Why is this in the news?

Republican nominee Donald Trump has insisted the emails are the smoking gun that prove Ms Clinton’s alleged corruption – despite the FBI previously declaring no criminal wrongdoing by the former Secretary of State. But Mr Trump’s constant calls for the imprisonment of Ms Clinton seemed to have little impact on her upward trajectory in the race to the White House. But as Ms Clinton leads by wide margins in all of the major national polls 11 days ahead of the election, the reemergence of the email scandal could slow down that momentum.

Where did the FBI find these emails?

The emails were reportedly found as FBI officials seized electronic devices belonging to top longtime aide Huma Abedin and her husband, former Congressman Anthony Weiner, amid his own sexting scandal, according to the New York Times. The emails were not related to the thousands of emails stolen from campaign chair John Podesta's account, as published by Wikileaks.

What does this mean for the campaign?

It remains unclear whether or not this will have a major detrimental impact to the Clinton campaign. NBC’s Pete Williams reported that a senior law enforcement official said there was no evidence that the emails in question were originally withheld from the FBI.

But the revelation further fuels the common perception that Ms Clinton is distrustful.

Loading....

How did Hillary Clinton respond?

“We are 11 days out from perhaps the most important national election of our lifetimes. Voting is already underway in our country,” she said. “So, the American people deserve to get the full and complete facts immediately.”

Her remarks echoed a statement issued by her campaign chair earlier that day.

Mr Podesta accused Mr Trump and the GOP of “baselessly second-guessing” federal investigators “in a desperate attempt to harm Hillary Clinton’s presidential campaign”.

"FBI Director Comey should immediately provide the American public more information than is contained in the letter he sent to eight Republican committee chairmen," he said. "Already, we have seen characterizations that the FBI is 'reopening' an investigation but Comey's words do not match that characterization. Director Comey's letter refers to emails that have come to light in an unrelated case, but we have no idea what those emails are and the Director himself notes they may not even be significant.

"It is extraordinary that we would see something like this just 11 days out from a presidential election."

How did Donald Trump respond?

Mr Trump issued a statement Friday afternoon celebrating the FBI and Justice Department’s decision to reopen the investigation, while singing a familiar song about Ms Clinton’s alleged corruption.

“Hillary Clinton’s corruption is on a scale we have never seen before,” he said. “We must not let her take her criminal scheme into the Oval Office.

“I have great respect for the fact that the FBI and the DOJ are now willing to have the courage to right the horrible mistake that they made. This was a grave miscarriage of justice that the American people fully understand. It is everybody’s hope that it is about to be corrected.”