The Thirteenth Sacrifice (Witch Hunt Series #1)

When young women start dying, Boston cop Samantha Ryan is the perfect person to investigate, for only she knows what the archais symbol carved into their flesh means. The last in a long line of ruthless witches, she grew up in a coven seduced by power and greed. And now she's sure that bad witches have returned to Salem. Reluctantly, Samantha goes undercover-into a town obsessed with black magic, into her terrifying past, and into thedark, newly awakened heart of evil.