undercover work

A good portion of the book also focuses on his undercover work with anti-KKK groups, most notably the Progressive Labor Party.

It really goes down in the dredges of the undercover work and the terrible, terrible things that happen.

Never said to anyone that I thought Lee was doing undercover work.

Bradley, realizing that the clever little Hindu boy would be of great value in his undercover work, had hired him.

Well, it's a combination of vice, narcotics, and undercover work.