They Built a Gallows for You and Me by Cody Higgins

Was the threat of death all we needed to die? When smiles act like monsters in the dark who are pretending to be friendly, it's hard to know where to put your trust. As a mysterious sickness starts killing the children in the town of Salinas, the townsfolk find themselves distraught and searching for answers. A new family in town seemed to bring forth the illness. Did they bring it with them? Are they causing it to happen? Or did the family stumble into something dark and sinister, something with witchcraft on its lips?