1st to Die by James Patterson

As the only woman homicide inspector in San Francisco, Lindsay Boxer has to be tough. But nothing she has seen prepares her for the horror of the honeymoon murders, when a brutal maniac begins viciously slaughtering newlywed couples on their wedding nights. Lindsay is sickened by the deaths, but her determination to bring the murderer to justice is threatened by her own personal tragedy. So she turns to Claire, a leading coroner, Cindy, a journalist and Jill, a top attorney, for help with both her crises, and the Women’s Murder Club is born.