The agent has worked 'undercover' in several countries.
He went 'undercover' as a drug dealer.
an 'undercover' investigation
(..) - Listen to me. Mia, I'm a cop. What are you talking about, Brian? What is this? Ever since the first time I met you, I've been undercover. I'm a cop. Oh, you bastard. You bastard. - Mia. - Get off of me, Brian! (..)2001 The Fast and the Furious
(..) are worth $. million... ...which brings the grand total to $ million plus. We're in the political crosshairs now, Brian. That's why you're undercover. You want that detective badge fast, kid. And you want to know something? The FBI can help, if you come through for us. (..)2001 The Fast and the Furious