A U.S. sailor was dishonorably discharged and sentenced to 18 years in a military prison Thursday after being found guilty of espionage while working for the Navy in Japan.

Bryce Pedicini, a former chief petty officer fire controlman, was convicted of attempted espionage, failure to obey a general order and attempted violation of a general order through a court-martial procedure. He was assigned to the guided-missile destroyer USS Higgins in Japan when he was taken into pretrial confinement last year.

According to the Naval Criminal Investigative Service, Pedicini delivered classified and national defense information for a foreign government official from November 2022 to May 2023. He engaged with the foreign official “under the guise of writing research papers,” it said. The Navy described that as a tactic U.S. adversaries increasingly use to obtain both classified and unclassified document.