Osaka was a member of the Japan Revolutionary Communist League National Committee, called the Chūkaku-ha, or “middle core faction.”
He was put on the wanted list in 1972[2] after being charged with murder, assault and other offenses.
According to police, on November 14, 1971, during a demonstration by students and other activists protesting the ratification of a Japan-U.S. treaty on the reversion of Okinawa, which degenerated into a riot, he attacked Tsuneo Nakamura, a 21-year old police officer, battering him with a steel pipe and setting him on fire with a petrol bomb. The officer died from his injuries.[2]
In June 2017, Osaka was arrested for obstructing police who raided an apartment in Hiroshima used as a hideout of the Chukaku-ha while searching for a fellow activist. They charged him with obstruction before later discovering his identity through DNA testing. He was charged with murder.
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