Nightlife — Thomas Perry

When the cousin of Los Angeles underworld figure Hugo Poole is found shot to death in his home in Portland, Oregon, homicide detective Catherine Hobbes is determined to solve the case. But her feelings, and the investigation, are complicated when Hugo simultaneously hires private detective Joe Pitt. As Joe and Catherine form an uneasy alliance, the murder count rises. Following the evidence, Catherine finds herself in a deadly contest with a cunning female adversary capable of changing her appearance and identity at will. Catherine must use everything she knows, as a detective and as a woman, to stop a murderer who kills on impulse and with ease, and who becomes more efficient and elusive with each crime.