In a Lonely Place by Dorothy B. Hughes
Dix Steele is back in town, and 'town' is post-war LA. His best friend Brub is on the force of the LAPD, and as the two meet in country clubs and beach bars, they discuss the latest case: a strangler is preying on young women in the dark. Dix listens with interest as Brub describes their top suspect, as yet unnamed.
Dix loves the dark and women in equal measure, so he knows enough to watch his step, though when he meets the luscious Laurel Gray, something begins to crack. The American Dream is showing its seamy underside.