During the first meeting of the Banns, talk to a lady named Ser Tamra to start the quest A Brewing Conspiracy. Although she does not know any names, she knows certain nobles that are still loyal to the now-deceased Arl Howe. When you talk with the Captain, depending on the options you select, he will inform the Warden of a man named "Dark Wolf", who can get information for a fee.
After this, when Warden arrives at to the City of Amaranthine, they are stopped by a messenger who provides a letter. The messenger says it's from "Ser Wolf" which hints that he knows he's being sought. Travel to the back gate to find a short suspicious man with a full knights helmet on. He says that he can get you information for a price of 50. If he's paid he finds the people meeting at Old Stark's Farm. This allows the Warden to travel there and quell the conspiracy.
When he finds out the information, the Warden has the option to either let him go, or 'arrest him', in which case he and some assassins will attack the party.
- At the completion of Crime Wave quest in Origins, Slim Couldry mentioned that there are people who call you the Dark Wolf. If you import a character that completed this quest to Awakening, you're able to both lie to the captain that you've never heard of this person, and confront the Dark Wolf on the fact that you're the real Dark Wolf.