More classified documents were found where they should not have been. Now, a retired Air Force lieutenant colonel will likely spend years in prison.

Lt. Col. Robert Birchum retired from the United States Air Force in 2018. He had spent most of his career working in the highest levels of U.S. intelligence. According to recently released court documents, Birchum served as the chief of combat intelligence for an unknown group in the Air Force. He later worked with “classified intelligence information” while at the Joint Special Operations Command, Special Operations Command and the Office of the Director of National Intelligence.

He knows the proper way to handle classified materials, but that didn’t stop the retired lieutenant colonel from illegally taking hundreds of classified documents, and then storing them at his Florida home.

Birchum pleaded guilty to one count of willful retention of national defense information. That’s a felony and carries a sentence of up to 10 years in federal prison. His plea agreement was signed in August of 2022 but wasn’t revealed until now. Authorities were tipped off about Birchum back in January of 2017. He is scheduled to make his initial court appearance on Feb. 21.

Among the documents Birchum had were two presentations from the National Security Agency, detailing the agency’s capabilities and identifying vulnerabilities in potential targets. Prosecutors said if those documents were released, it would have causes exceptionally grave damage to the national security of the United States.