Dope: A Novel by Sara Gran (2006)

Set in 1950s New York City. Joe (Josephine) is a ex-junkie who gets hired to find a young woman who is a drug addict, and gets framed for murder. Really atmospheric and reminiscent of noir novels like Cain and Chandler without being a direct aping of the style. Gran gives her own modern style to the writing, which is really delightful. Loved the settings, and pretty interesting take on drug addiction.