Spoilers (added more info)
Edit: I never thought this would reach over 20k views... gods. xD
If you find Dupais after you're done with the mother quest, you can have a chat with him... 8D And it's another reveal of the Murder knife!
He's found in Darktown, if you didn't send templars after him or killed him yourself. If you can talk him down using the Diplomatic option (only way he'll stay alive I think), he'll be at the same place in Darktown after the whole event.
Don't know if day/night makes a difference to his apperance.
