The agent has worked 'undercover' in several countries.
He went 'undercover' as a drug dealer.
an 'undercover' investigation
(..) They're like fucking Indians. You're not gonna see them. You'll hear about them through me or Captain Queenan. You will not ever know the identity of undercover people. Unfortunately, this shithole has more leaks than the Iraqi navy. - Fuck yourself. - I'm tired from fucking your wife. (..)2006 The Departed
(..) Hey, fuckhead, that's Jackie's nephew. What? "Oh," fucking what? Get the fuck out of here. Sorry I'm late. Staff Sergeant Dignam is our liaison to the undercover section. His undercover work is extensive. He's here to give us his report. Sergeant Dignam. Okay, my people are out there. (..)2006 The Departed