14th Deadly Sin: (Women's Murder Club 14) by James Patterson
A new terror is sweeping the streets of San Francisco. And the killers look a lot like cops... As Detective Lindsay Boxer investigates whether the perpetrators are brilliant impostors or police officers gone rogue, she receives a chilling warning to back off. On the other side of the city, an innocent woman is murdered in broad daylight in front of dozens of witnesses. But there are no clues and no apparent motive. With killers in disguise, a maniac murderer on the loose, and danger getting ever closer to Lindsay's door, could this be one case too many for the Women's Murder Club?