G-men
G-men are the government's tough guys. They work for the FBI, CIA, and all the other sneaky spy groups.
"The G-men are watching me.", A guy who got caught cheating on taxes.
A movie poster from the 30s: "G-men vs. the mob!", Not very original, but it worked.
A kid in class said, "My uncle is a G-man, he kicks butt."