Mission 53 – Interrogate Cavar's Foremen
Go pay a call on Virgil Gaulthier. He likes to hang out right near the entrance to this area, so you could be one whistle lure away from your next objective.
Just be careful – unlike regular take downs, interrogations take some time, and other enemies may wander onto the scene.
Follow the informer's tip to trailer full of money, and an ad hoc execution.
It's possible to take the money and leave the goons alive, if you're feeling particularly ninjaesque. If not – open fire. Just remember to call your consigliere to take all the loot off your hands afterwards.