That’s because in a free society there is no national police force. Criminal justice, along with all the power a criminal-justice system entails, is best left at the state and local level. National police forces are inherent to totalitarian regimes, such as those in Iran, North Korea, and China.Thus, it’s not a coincidence that the Framers did not provide for a FBI in the Constitution, just as it isn’t a coincidence that our American ancestors did not have a FBI for more than a century after the Constitution called the federal government into existence.
https://www.fff.org/2019/05/30/abolish-the-fbi/
