Story highlights Official says an unnamed Navy officer was arrested eight months ago

The officer is charged with spying, making false statements and adultery

(CNN) A Navy officer has been charged with espionage and attempted espionage, among other accusations, in a proceeding that has been designated a national security case.

Three U.S. defense officials named the Navy officer as Lt. Cmdr. Edward Lin. Multiple attempts by CNN to reach Lin, his family, or his attorney have been unsuccessful.

Lin was arrested about eight months ago, but information about his case didn't become available until after a preliminary hearing Friday. Key parts of the charging sheet are still redacted.

A defense official told CNN Monday that investigators are still trying to determine who Lin was spying for, though China and Taiwan are possibilities.

The full scope and breadth of the information provided is unclear, the official said, but the suspicions stem from the work he was doing at the time of his arrest. The official said investigators found enough evidence to be able to bring charges, but much more is needed to determine exactly what information was passed and to whom.

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