A Murder of Crows

A Murder of Crows is a quest in Act 3 of Dragon Age II wherein a man claiming to be an Antivan noble tells you that he is pursuing a dangerous assassin. He says he has been attempting to bring the criminal to justice but that his quest has become personal since the man has killed several of his subordinates. When asked why he has come to you for help, he says that the assassin is an elf and is blending in with the nearby Dalish tribe so he needs someone more familiar with the Dalish to track him down.

Upon ascending the Sundermount and fighting a Varterral you come across the assassin -- it's Zevran! You can choose to take him in or let him go; in the process, you can flirt with him. If you let him go, he runs off; as soon as you leave the cave, the man who "hired" you attacks you and Zevran shows back up to help you fight him off.