Scarlet Widow by Graham Masterton

London, 1750: Beatrice Scarlet is the apothecary's daughter. She can mix medicines and herbs to save the lives of her neighbours but, try as she might, she can't save the lives of her parents. An orphan at just sixteen, Beatrice marries a preacher and emigrates to America.

New Hampshire, 1756: In the farming community where Beatrice now lives, six pigs are found viciously slaughtered, slices of looking-glass embedded in their mouths. According to scripture this is the work of Satan, but Beatrice suspects the hands of men. As she closes in on the killer, she must act quickly to unmask him or become the next victim herself...