Former National Security Agency Contractor Harold T. Martin III plans to plead guilty to willfully retaining national defense information, just one of 20 charges brought against him in October 2017, according to Wednesday court filings.

Martin was arrested from his home in Maryland in August, where prosecutors found classified government materials from 1996 to 2016, including an email chain marked as “Top Secret” and printed from an official government account.

At the time of his charging, prosecutors pointed to communications Martin had in Russian as reason why he might seek shelter in a foreign government if freed.

Martin had worked for government contractor Booz Allen Hamilton since 1996.