Its main function was as a civilian counterpart to the military's Kempeitai and Tokkeitai, and it can be considered roughly equivalent to the Federal Bureau of Investigation in the United States in terms of combining both criminal investigation and counter-espionage functions.
On 17 April 2007, Yoshimi and fellow historian Hirofumi Hayashi held a press conference and announced the discovery of documents in the archives of the Tokyo Tribunal that demonstrate that Tokkeitai members coerced or otherwise forced women from Indonesia, Indochina, and China into sexual slavery.