Evil at Heart by Chelsea Cain

Gretchen Lowell is the "Beauty Killer", a serial murderer who has escaped from prison and (because of her gorgeous looks) has become an obsession with both the print and TV media. Archie Sheridan, a cop, survived being repeatedly tortured by Gretchen and now has checked himself into a mental hospital to regroup and try to conquer his addiction to Vicodin. When dead bodies start showing up around Portland, Archie and his partner, Henry, wonder if Gretchen has started a new killing spree or if a copycat is at work. Reporter Susan Ward wants to write a book about the "Beauty Killer" and has been trying to get Archie to speak to her while he's been in the hospital. As in the previous two books in the series, Archie, Henry, and Susan become immersed in Gretchen's mindgames and machinations while trying to stop her from killing anyone else or becoming victims themselves. A gruesome yet suspenseful book that's better than the last book in the series, Sweetheart. It helps to read the books in order, though.