Marta, the new wife of Callie's boyfriend, was the killer of the Goddesses. She was the "Fifth Petal" - the descendant of Sarah Good, one of the witches executed in the early days of Salem. Marta had spent a lifetime harboring a grudge against the Whitings and anyone else she felt slighted by. Including the Goddesses. It is revealed that she was the killer late in the book after she poisoned her new husband, new step-son, and tried to poison Callie. It was Rafferty who saved her.
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