The Last Precinct by Patricia Cornwell

All the familiar faces--friend and foe--are here: police captain Marino, Kay's niece Lucy, the so-called Werewolf murderer, and (in memoriam) Kay's lover Benton Wesley and his killer, Carrie Grethen. Kay, who nearly killed the Werewolf in self-defense as Black Notice came to a close, now finds herself the target of a corrupt police investigation that will dredge her darkest secrets from the deepest corners of her past.