Beneath the Soil - Sampson, Fay

Suzie Fewings and her family are on a family-history trip when they hear a gunshot, and encounter a local farmer and his wife, who seem strangely agitated. Two days later, the wife is dead. Suzie is convinced there's more to this than meets the eye, but the police don't seem interested, and Suzie soon feels like she's being watched ...