True. The Constitution defines only 3 federal crimes: treason, piracy and counterfeiting. But it authorizes Congress to create new federal offenses. Since the Founding, Congress has created over 10,000 federal offenses, and that is why we have the FBI.
To get rid of the FBI, you need to pare down the number of federal offenses and restore police powers to the states.
Even so, does that give the FBI arrests powers within the States?
I don’t believe that it does.