The original Central Security organization was present in the times when 'old humans' ruled the planet Hera and passed on to the genetically engineered Heran species when they came to take control of the government and world.
Central Security were a feared organization as well as brutal. They were known to detain suspects and use truth serum to extract vital information after which they would execute the offender. By the time of the Heran Crisis, Central Security was busy staging rapid strikes against 'radical' rebel groups by using a powerful planet-wide transporter to hit the resistance bases. (TNG novel: Infiltrator)