Synopsis from Goodreads

Small towns are nothing if not friendly. Friendship, Wisconsin (population: 689 688) is no different. Around here, everyone wears a smile. And no one ever locks their doors. Until, that is, high school sweetheart Ruth Fried is found murdered. Strung up like a scarecrow in the middle of a cornfield. Unfortunately, Friendship’s police are more adept at looking for lost pets than catching killers. So Ruth’s best friend, Kippy Bushman, armed with only her tenacious Midwestern spirit and Ruth’s secret diary (which Ruth’s mother had asked her to read in order to redact any, you know, sex parts), sets out to find the murderer. But in a quiet town like Friendship—where no one is a suspect—anyone could be the killer.