This period started on March 31, 1964, with the removal of the civilian government by military forces and ended in 1984.
It acted as a political police, using torture and other counter-insurgency methods, with a focus on anti-communism.
Several political activists, intellectuals, artists, college students and journalists were interrogated and at times tortured by the DOI-CODI throughout its existence.
Each state had a DOI unit subordinated to CODI, which had the role of centralizing the operations.
The largest DOI-CODI, that of São Paulo, had at its peak nearly 250 agents, occupying a large building on Tutóia street.