WASHINGTON — A linguist for the Navy in Bahrain is charged under the Espionage Act with possessing classified documents — some of which ended up in public archives of the Hoover Institution at Stanford University.

James Hitselberger, who is fluent in Arabic, had the job as a federal contractor of translating documents for the Joint Special Operations Task Force-Gulf Cooperation Council. The council contains a unit conducting unconventional warfare, counterterrorism and special reconnaissance.

An FBI affidavit unsealed Monday says Hitselberger copied documents last spring that discussed military troop activities in the region and gaps in U.S. intelligence in Bahrain. His superiors later found the material stashed in his backpack, and investigators said they subsequently discovered additional classified material at Stanford in the “James F. Hitselberger Collection.”...