Look to an Old Friend
Speak to Elling Trias in Stormwind.Description
That Marzon would be contacting a member of the Defias and have ties to Lescovar...Having killed VanCleef and Thredd, it would be hard to see Lescovar brought to proper justice, as your evidence is nothing without their testimonies. That is not even considering the fact that Lescovar is a noble and well connected. It effectively makes him above the law.
You'll need other help. I loathe to do so, but there is someone I know that will aid us. You'll find Trias in the Trade District of the city.
Completion
Rewards
You will receive: 1 50 if completed at level 80Gains
Upon completion of this quest you will gain:- 250 experience