The journalist, YouTuber and comic book writer Douglas Ernst (who I have interacted with in his livestreams and who seems very trustworthy) said that he once tried to join the FBI (shortly after he got out of the Army).

During the interview process, they asked him various test questions. One of them was whether he would steal a large sum of money if he knew for certain that he would get away with it. He revealed to them that he had actually once had such a chance, and chose to do the right thing by reporting the accounting error instead of keeping the money like he could have.

They didn't hire him, and he suspects that it was because of his answer to that question. They don't want incorruptible agents, as an incorruptible agent is an uncontrollable agent who might disobey orders or become a whistleblower. They only want people that they can corrupt and fully control.