Hillary Clinton and her top aides failed to comply with U.S. State Department policies on records by using her personal email server and account, possibly jeopardizing official secrets, an internal watchdog concluded in a long-awaited report (pdf) on Wednesday.

Clinton also never sought permission from the department's legal staff to use the server, which was located at her New York residence, a request which—if filed—"would not" have been approved, the report by the agency's Office of the Inspector General (OIG) states.

"At a minimum, Secretary Clinton should have surrendered all emails dealing with Department business before leaving government service and, because she did not do so, she did not comply with the Department's policies that were implemented in accordance with the Federal Records Act," it continues.

The findings are the latest development in the email scandal that has persisted throughout Clinton's presidential campaign to little effect—but its conclusion was unexpectedly critical.

And it could spell trouble for the former secretary of state in the final stretch of the election, as public trust in Clinton continues to decline while polls show her rival Bernie Sanders has become the most formidable candidate against Republican presumptive nominee Donald Trump.

As Politico's Rachael Bade, Josh Gerstein, and Nick Gass write:

The watchdog’s findings could exact further damage to Clinton’s campaign, and they provide fresh fodder for Trump, who has already said he will go after Clinton for the email scandal “bigly.” The Democratic frontrunner’s bid for the White House has already been hindered by high unfavorability ratings, with people saying they don’t trust her.

The report represents the latest pushback — in this case by a nonpartisan government entity — against her campaign’s claim that she did not break any rules and that her use of a private server was completely allowed.

In fact, technology staff in the Information Resource Management (S/ES-IRM) office who brought up concerns about Clinton's use of her private server were reportedly instructed not to question the arrangement.

"In one meeting, one staff member raised concerns that information sent and received on Secretary Clinton’s account could contain Federal records that needed to be preserved in order to satisfy Federal recordkeeping requirements," the report states. "According to the staff member, the Director [of S/ES-IRM] stated that the Secretary's personal system had been reviewed and approved by Department legal staff and that the matter was not to be discussed any further. As previously noted, OIG found no evidence that staff in the Office of the Legal Adviser reviewed or approved Secretary Clinton's personal system."

Other staff from different offices were also instructed "never to speak of the Secretary's personal email system again."

On Wednesday, Clinton's campaign was quick to point out that the report's criticisms also extended to the State Department in general, which the OIG found to be riddled with "longstanding, systemic weaknesses related to electronic records and communications" and noted that other department officials, including former Secretary of State Colin Powell, also used personal e-mails while in office.

The findings were issued a day after a group of U.S. intelligence veterans, including William Binney, John Kiriakou, and Diane Roark, published an open letter to President Barack Obama urging him to expedite the forthcoming FBI report on Clinton’s alleged email security violations.

"The question is not whether Secretary Clinton broke the law," the letter states. "She did. If the laws are to be equally applied, she should face the same kind of consequences as others who have been found, often on the basis of much less convincing evidence, guilty of similar behavior."