Unfortunately I disagree with some of my colleagues below. If the agent has in fact been deceiving and corrupt..and you have damages..it's time for an attorney.
The agents Broker or Manager will appreciate your comments however in most cases they will do very little. This is because the manager or broker gets paid each time the agent makes a dollar. In 25 years I know of one agent who got fired and I was the one to personally escort him to the door.
My suspicion is this matter is about security deposit? If so..and the steps I gave you before have not worked..it is time for an attorney.
If the question is one about ethics..you will need to review the link provided by one of the agents below and see which particular ethics violations you suspect. Then take this and file a formal complaint with the Northern VA Assoc. of Realtors. However, this is a committee of peers..so don't expect much here either unless the violations are severe and actual damages did occur.
Your next step...if you don't get what you like would then be to go to the state. Link again provided below. You will need to be specific and provide proof of your damages.
Sorry if this is not what you want to hear..but best to shoot straight.
Erik J. Weisskopf, ABR,CDPE,CRS,GRI
Re/Max Distinctive Real Estate