桂太郎
During his office at Chief of Police Bureau (1903-1904 / 1908-1911) for the first and the second Katsura Tarō Cabinet, he commanded the investigation of the High Treason Incident in 1910, when police arrested socialist-anarchist Kōtoku Shūsui and others prosecuted to the death penalty. Performing the Imperial compilation, Arimatsu was administered an Imperial nominee to the House of Peers on August 24, 1911 and with resignation from government official, enrolled the largest Parliamentary group "Kenkyūkai", among members with wide social background including marquis, earl and baron, Imperial nominee, as well as millionaire.