State Department staffers who worked to respond to congressional requests for documents about the Sept. 11, 2012 Benghazi attacks discovered in June 2013 — a year earlier than has previously been reported — that Hillary Clinton used a personal email account.

The revelation, which was included a scathing 83-page State Department inspector general report released on Wednesday, “raises very serious questions” about the Obama administration’s lack of cooperation with the congressional committees that have looked into the Sept. 11, 2012 Benghazi attacks, said Matt Wolking, the press secretary for the House Select Committee on Benghazi.

[dcquiz] “The evidence uncovered by this independent watchdog showing State Department senior officials were well aware in June 2013 of Benghazi-related personal emails but ‘took no action’ raises very serious questions about the administration’s lack of cooperation with Congress,” Wolking told The Daily Caller.

The Committee, which is chaired by South Carolina Rep. [crscore]Trey Gowdy[/crscore], has engaged in an increasingly bitter battle with Obama’s White House, the State Department and the Defense Department over production of records it says are relevant to its investigation. Many Democrats have accused the Select Committee of unnecessarily prolonging both the Benghazi investigation and of unfairly focusing on her use of a personal email system.

But the June 2013 discovery of Clinton’s emails among Benghazi-related records suggests that both probes could have been settled by now.

Prior to Wednesday’s watchdog report, the State Department had identified the summer of 2014 as the period when staffers working on Benghazi document productions had identified Clinton’s personal email address. The discovery of the email address — which was known to many top officials within the State Department during Clinton’s tenure but apparently not to lower-level staffers sifting through Benghazi records — reportedly served as the catalyst for an official State Department request for Clinton’s work-related emails.

That claim, which was first reported by The Washington Post last year, undermined Clinton’s insistence that the State Department requested her emails as part of a widespread effort to obtain work-related emails from all past secretaries of state.

But if the discovery of Clinton’s personal email by State Department staffers looking at Benghazi documents served as the trigger for the request of all of her work emails, the new IG report raises questions about why that initiative wasn’t undertaken the year before.

The watchdog’s report states:

Specifically, in early June 2013, Department staff participating in the review of potential material for production to congressional committees examining the September 2012 Benghazi attack discovered emails sent by the former Policy Planning Director via his Department email account to a personal email address associated with Secretary Clinton.

The policy planning director mentioned in the report is Jake Sullivan. The longtime Clinton aide was one of the most prolific senders of classified information that ended up on Clinton’s server. He is reportedly of keen interest to the FBI, which is investigating whether classified information was mishandled on Clinton’s server.

The IG report released on Wednesday added that the June 2013 discovery prompted a debate within the State Department in the ensuing weeks in which senior Department officials “discussed the Department’s obligations under the Federal Records Act in the context of personal email accounts.”

That debate appears to have done nothing to further the release of Clinton’s emails. She did not hand them over to the State Department until December 2014.

The June 2013 discovery — which was made while the House Oversight and Government Reform Committee was investigating Benghazi — is key because it shows that the State Department was aware that emails to and from Clinton likely existed which could have provided valuable insight to Congress about the Benghazi attacks. (RELATED: Hillary Told Daughter That Terrorists Were Behind Benghazi Attack The Night It Happened)

The State Department did not respond to requests for comment for this report.

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