List of Dexter characters
On a visit to his sister, Dexter and Debra both feel as if they have been drugged; just before he passes out, Dexter sees Hannah standing over him. When he later regains consciousness, Dexter begins investigating Hannah, and finds that she has changed her name and married Miles Foster (Julian Sands), a wealthy businessman. Dexter goes to see Hannah, who says that she had wanted him to kill Foster, but changed her mind after realizing she is still in love with Dexter. Foster warns him to stay away from Hannah, and has him beaten up. Dexter goes to Foster's boat to protect Hannah, but finds that she has already killed him. The two of them dispose of the body, and promise to watch out for each other. The two end up having sex and rekindle their relationship.
Dexter (season 4)
Dexter learns of Lundy's analysis, steals his records, and uses his own skills to sneak into the building and catch sight of the Trinity Killer in the act of dispatching his third victim. Dexter follows the killer to his home, and is very surprised to learn that he is Arthur Mitchell: husband and father, deacon at a local church, and leader of the "Four Walls One Heart" homebuilding charity organization. Dexter continues to watch him and comes to admire his ability to balance his killings along with his family and work lives. Using the alias "Kyle Butler", Dexter joins Arthur's church, befriends him, and learns from him how to improve his own relationship with Rita and his family, giving over his condo to Debra while transferring his killing implements into a shed behind their house. Meanwhile, the Miami police learn that the Trinity Killer places a small amount of cremation ashes at each murder scene, and identify that Trinity and the ash share similar genetics but otherwise cannot match Trinity to any criminal records.