 They were often suspected by the Russian government of being used as intelligence-gathering tools for Japan, and having contributed to Russia's defeat in the Russo-Japanese War.Though the Japanese residents' association in Vladivostok was officially disbanded in 1912 under pressure from Russia, Japanese government documents show it continued to operate clandestinely until 1920, when most Japanese in Vladivostok returned to Japan.The initial landing of Japanese forces in Vladivostok after the October Revolution was prompted by the April 4, 1918 murder of three Japanese living there, and the Nikolayevsk Incident which occurred in 1920.