Some of the FBI files on the agency’s investigation into Hillary Clinton’s use of a private server exclusively for government business while serving as secretary of state could be given to a House oversight committee as early as this week, a congressional source confirmed with Fox News on Sunday.

The matter has been progressing since early July, when a formal request was made by Congress for the file -- the remaining block appears to rest within the Justice Department. 

The FBI, after interviewing Clinton last month, concluded its investigation of Clinton's use of a private server, confirming publicly that 113 classified emails were sent and received by Clinton, as well as 2,000 that were classified after the fact.

FBI Director James Comey said investigators found at least three emails that contained classified markings, adding that the Democratic presidential nominee was "extremely careless." However, he did not recommend criminal charges, and the Justice Department closed the case.

While Clinton has insisted nothing was marked classified at the time, the investigation found otherwise, with the emails containing a portion marking (C for confidential, the lowest level of classification). Fox News first reported that some of the emails were marked classified in June. 

The House Oversight Committee questioned Comey for over five hours in July after he said no reasonable prosecutor would pursue criminal charges.

The Oversight Committee has formally asked if Clinton committed perjury during her Benghazi testimony in October 2015, because her statements to Congress appear to conflict with the FBI's findings. Clinton has maintained she was truthful in her FBI interview.

Fox News is told that the FBI and Justice Department have confirmed the receipt of the committee’s request.

Congressional investigators -- led by House Committee on Oversight and Government Reform Chairman GOP Rep. Jason Chaffetz of Utah -- have been aggressively seeking the entire file, including a summary of Clinton’s interview, known as a "302."

However, the document is considered highly classified, because Clinton's FBI session included questions on the 22 top secret emails that are too damaging to national security to make public.

Note that, it is standard for FBI interviews not to be recorded, so there is no transcript, but agents take extensive notes and they form the basis for the written report known as the "302." 

The possible release of the file to congressional investigators was first reported by CNN. 

Catherine Herridge is an award-winning Chief Intelligence correspondent for FOX News Channel (FNC) based in Washington, D.C. She covers intelligence, the Justice Department and the Department of Homeland Security. Herridge joined FNC in 1996 as a London-based correspondent.