You see a trio of men in Stormwind investigator outfits kneeling over a pair of corpses, apparently quite vulnerable. "You might want to know there's a thuggish-looking guy over there," you say, jerking your thumb in the direction that you saw the guy in. Just as these words exit your mouth, you notice that the thug was apparently following you, but seems to have just frozen up at the sight of four armed people facing him. From the look on his face, he's just realized that neither attacking you nor running is of any use. "I surrender," he says, putting up his hands. "Great," says the most smartly-dressed of the investigators as the other two awkwardly tie up the thug. "That'll save you a headache later." "So what do we do with him, Laine?" asks the investigator who's worse at tying up the thug. "We find out what he knows," says Laine.
Try to keep the thug calm. That should make him easier to interrogate. Try to force a confession out of him before he gets too comfortable. See what Laine's plan is. Let him deal with the thug...at least to begin with. Demand payment.