Japan's Chief Cabinet Secretary says a Japanese professor from Hokkaido University has been released from detention in China and has returned home.
Yoshihide Suga told reporters on Friday that the professor in his 40s arrived in Japan earlier in the day, and is believed to be in good health.
Also announcing the release on Friday, Chinese Foreign Ministry spokesperson Geng Shuang said national security authorities investigated the professor because he was collecting materials concerning China's state secrets at his hotel.
Geng said the professor admitted to the act and showed remorse, so the authorities took steps to release him on bail. He added that the man has left for Japan.
The professor was taken into custody in September while visiting Beijing at the invitation of the Chinese Academy of Social Sciences. China has not said why he was detained.
Earlier this month, Prime Minister Shinzo Abe requested the professor's early release when he met Chinese Premier Li Keqiang on the sidelines of a regional forum in Thailand.
Li told Abe that he had taken note of Abe's request.