Cross the Line - Detective Billie McCoy, #6

Detective Billie McCoy is on edge. As are the entire police force after a random killing spree sees six cops executed in the last two weeks. No clear motive. No pattern to the murders. No arrests. The city is no longer a safe place. But it's not only the murders that has Billie so perturbed. Her concerns rise when she finds herself held at gunpoint by a madam of a high-class brothel who has requested her audience.
She offers Billie an ultimatum: apprehend a common enemy in exchange for information regarding the safety of one of Billie's closest friends. With time against her to save her friend, Billie has no choice but to bow to the madam's commands. She and her three best friends are drawn into a dangerous pursuit, one that could easily take a cruel turn and backfire in their faces. Dealing with intimidation, corruption and needless bloodshed, the twisted truth will be revealed.