Nice Work, by Denise Weeks
Jacquidon Carroll has problems ... She's diagnosed with diabetes and laid off from her job the same week, but that's nothing compared to being a suspect in the murder of her ex-boss…Jacquidon is convinced her replacement—a young woman recruited from an Internet sex site—is the real killer. To clear herself, Jacquidon steals information from the boss’s computer and the young woman's diary. The clues lead through a network of local sex clubs and the seamy underside of the BDSM (S & M) lifestyle. By the time Jacquidon gathers her evidence, the murderer is on the same page—and intends to stop her.