Michael C. Hall: "A new character will help Dexter experience a dynamic that he hasn't up to this point. An older female. This never really been a real time exploration for Dexter. We found out about how his birth mother was killed in front of him, but he never had a real time flash-in-blood, somewhat maternal figure with whom to interact."
Click here to hear the audio interview!
Thanks to @Cosmiccca for the heads up!