The FBI has said that it is investigating newly-discovered emails related to Democratic presidential candidate Hillary Clintons personal server.

“The FBI has learned of the existence of emails that appear to be pertinent to the investigation. Case reopened,” US House Oversight Committee Chairman Jason Chaffetz tweeted on Friday.

According to a copy of a letter by FBI Director James Comey to Chaffetz, new emails had emerged recently that appeared to be linked to the Clinton email probe completed in July, Xinhua news agency reported.

“I agreed that the FBI should take appropriate investigative steps to determine whether they contain classified information, as well as to assess their importance to our investigation,” said Comey in the letter.

After a year-long investigation the Federal Bureau of Investigation (FBI) in July recommended no criminal charges against Clinton in its email probe and the Justice Department then closed the investigation.

At a press conference in March 2015, Clinton acknowledged that she had exchanged about 60,000 emails from her private email account during her stint in the Obama administration, among which about half were personal and thus deleted.

All emails were sent and received via a private email server based at Clinton’s home.

In response to requests from the State Department, the Clinton camp turned over the other half, roughly 30,000 emails to the State Department in December 2014.

The controversy surrounding Clinton’s email practices again burst into public view in August 2015 after the inspector general for the intelligence community revealed that two of the thousands of emails held by Clinton contained top-secret information.

The revelation then trigged a federal investigation into whether Clinton had mishandled sensitive information.