The Economic Investigation Brigade asked me to make a statement and then let me go home. Why?

It is a normal process for the Economic Investigation Brigade to summon and take notes. Taking notes is just to understand the investigation. As long as you haven't done anything illegal or criminal, you'll be fine as soon as you finish the transcript. Legal basis: Article 119 of the Criminal Procedure Law of People's Republic of China (PRC), a criminal suspect who does not need to be arrested or detained may be summoned to the designated place of the city or county where the criminal suspect is located or to his residence for interrogation, but the certificate of the people's procuratorate or the public security organ shall be produced. A criminal suspect found at the scene may be summoned orally, but it shall be indicated in the interrogation record.