Scourge: Triskellion Book One in Bloomington, MN

Angela Benson, a rookie detective with the NYPD, is partnered with an old pro named Joe Anderson. The pair are learning each other's traits when they start an investigation into a homicide case with disturbing evidence―the victim is mutilated. As other bodies begin to pile up, they only have one eyewitness that's gone missing, forcing them to work against time and the system, trying to stop the guilty and end the reign of terror.
As they begin to uncover the supernatural aspects of the deaths, they discover that the killers seem to be looking for something ancient and vital that has found its way to NYC. A natural predator is on their heels, seemingly pure of heart, based on its need to confess each death as a sin. When it crosses paths with the detectives, it needs Angela, drawing her into its world of magic and mayhem.
As Angela takes the first steps toward her destiny, honing her skills as a detective and unlocking her newfound mystical abilities, she forges into a secret war to protect mankind from an evil the world has never known.