ELI5 Special Agents - what makes them special vs just ‘agents’?

What’s the difference between the police department and the sheriff’s department? What was the sting operation the FBI conducted on members of congress in the 1980s? Did we not have a foreign intelligence service before the CIA was created? What was the Secret Service’s original role? ... we explain like I'm five Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: davedoeslife, chrismichaels3000, fouram, mildlysuspicious, firesondiego, zyonker, nickppapagiorgio, hugglyfe, acrobatic_pandas and dew2459 To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter: https://www.twitter.com/eli5ThePodcast/ or send us an e-mail: [email protected]