The State Department has opened a formal inquiry into the possible mishandling of classified information by former Secretary of State Hillary Clinton and her aides.

Clinton and her staffers still have security clearances which could be revoked depending on the outcome of the investigation.

The inquiry will be looking into whether Clinton and her aides violated government rules with her use of a private email server while serving as the nation's top diplomat.

The State Department has opened a formal inquiry into the possible mishandling of classified information by former Secretary of State Hillary Clinton and her aides

Senate Judiciary Committee Chair Chuck Grassley, R-Iowa, confirmed the department's formal inquiry to Fox News.

Clinton's spokesman, Nick Merrill, said: 'Nothing's been more thoroughly dissected. It's over. Case closed. Literally.'

A State Department official told MailOnline: 'Due to privacy considerations, the Department cannot provide any information regarding any current or former employees' security clearance or access to classified information.'

Earlier this month Senator Grassley launched another investigation into Hillary Clinton over whether the former secretary of state meddled in a Bangladeshi corruption probe to help a Clinton Foundation donor.

'This new evidence of pay-to-play and special treatment reinforces the appearance that donations to the Clinton Foundation resulted in favorable treatment by Secretary Clinton's State Department,' Grassley said.

Senate Judiciary Committee Chair Chuck Grassley (pictured), R-Iowa, confirmed the department's formal inquiry

Clinton's spokesman, Nick Merrill (left), said: 'Nothing's been more thoroughly dissected. It's over. Case closed. Literally.'

The Daily Caller first reported Grassley's move after the publication's Investigative Group published a piece in May saying that Clinton had sent top U.S. diplomats to pressure Bangladesh's Prime Minister Sheik Hasina, and her son Sajeeb Wazed, as the country investigated Clinton friend Muhammad Yunus for corruption.

Nothing's been more thoroughly dissected. It's over Clinton's spokesman Nick Merrill

Donald Trump has continued to draw attention to Clinton's email troubles throughout his time as president.

Last week Trump blasted 'crooked' Hillary Clinton - less than 24 hours after it was revealed he is being investigated over obstruction of justice.

Trump slammed his former political rival in a series of tweets, after earlier terming a probe by a special counsel 'the single greatest WITCH HUNT in American political history - led by some very bad and conflicted people!'

Last week Trump blasted 'crooked' Hillary Clinton - less than 24 hours after it was revealed he is being investigated over obstruction of justice

'Why is that Hillary Clintons family and Dems dealings with Russia are not looked at, but my non-dealings are?' Trump asked on Twitter

'Why is that Hillary Clintons family and Dems dealings with Russia are not looked at, but my non-dealings are?' Trump asked on Twitter.

'Crooked H destroyed phones w/ hammer, 'bleached' emails, & had husband meet w/AG days before she was cleared- & they talk about obstruction?' Trump asked, combining his attacks on Clinton with gripes about the evolving Russia investigation.

The tweet revived two attacks from the 2016 campaign, that a Clinton aide destroyed some of her multiple communications devices, and that her team used software to get rid of old emails.

Trump's attack that Clinton 'bleached' her emails was a reference to her use of BleachBit, an open source software to delete emails she considered private.

Donald Trump has also continued to draw attention to Clinton email troubles as president

His mention of her destroying phones was a reference to information, gleaned from FBI documents released in September, than an aide destroyed two Clinton mobile phones that were no longer being used with a hammer.

Trump went after Clinton for her email practices during the second presidential debate in October – where he also said he would appoint a special prosecutor to investigate her.

'The thing that you should be apologizing for are the 33,000 e-mails that you deleted and that you acid washed,' Trump said.

'You delete 33,000 e-mails. And then you acid wash them, or bleach them, as you would say—a very expensive process,'Trump said.