Jennifer Carpenter
Jennifer Leann Carpenter (born December 7, 1979) is an American actress. She is known for playing Debra Morgan, the adoptive sister of the title character of the Showtime series "Dexter", for which she earned a Saturn Award in 2009, and also for playing Rebecca Harris in the CBS television series "Limitless".
Dexter (season 2)
Starting with this season, the show no longer adapts the Dexter novels. Taking place a month after the first-season finale, Dexter has been unable to kill anyone due to Sgt. James Doakes monitoring his activities and his sister Debra now living with him as she recovers from her traumatic experiences concerning Brian, the Ice Truck Killer. Dexter also realizes that he's having trouble killing even when he has the opportunity, due to feelings of guilt over killing his brother Brian.