The children of witches - Sherri Smith

Married to a drunken tavern-keeper, Anna Wirth takes solace in her two sons, hard-working Konrad and the beautiful, flaxen-haired Manfred, who sings like an angel and who, some say, has been touched by God. But at the same time, Anna is desperate to prevent people finding out the truth about her younger son. That he is not like other children: he does not communicate, doesn't make eye contact, lives in his own private world, endlessly collecting and arranging piles of leaves and stones.
When rumours of witchcraft sweep through the town, Manfred is seized by those who would use him to pursue their own agenda. As innocent townsfolk are accused, a climate of fear prevails. No one is safe - and at the heart of the terror is Anna's own son.
As the death toll mounts, Anna realizes there is only one way to stop the madness. But can she act against a mother's deepest instincts?