The State Department identified nearly 600 security violations in its now-completed review of email records of dozens of former agency officials and aides to former Secretary of State Hillary Clinton.

The investigation, which covered the 33,000 emails Clinton provided for review, found 91 "valid violations" attributable to 38 individuals, some of whom may face disciplinary action. Another 497 violations could not be tied to any specific person.

A nine-page unclassified report was sent to Iowa Republican Sen. Chuck Grassley, who is leading the congressional oversight of the security review, in a letter from Assistant Secretary of State for Legislative Affairs Mary Elizabeth Taylor dated Oct. 16.

The 36-month inquiry sought to determine "if any of the emails under review represented a failure to properly safeguard classified information" and whether any individuals could be determined to bear individual responsibility. Investigators reviewed thousands of documents, received hundreds of statements, and met with dozens of current and former State Department employees. The review was completed on Sept. 6.