Jap Ex-Fleet Admiral Put in Sugamo Prison By United Press Former Fleet Admiral Osami Nagano has been arrested and placed in Sugamo prison as a war criminal suspect on order of the international prosecution section. Nagano, once a delegate to the disarmament conference at Geneva, served as commander of the Third Training Squadron, as director of the Naval Academy, vice chief of the Naval Staff board, commander of the Yokosuka naval station, supreme war councilor in 1935 and commander-in-chief of the combined fleet and first fleet in 1937.