The Dead of Summer by Jean Rabe

Shouts of delight turn to screams of terror when a carnival ride goes berserk at the Spencer County Fair. Sheriff Piper Blackwell must contain the chaos and investigate the possible sabotage, even as she tries to solve a local businessman's horrific murder.

But managing two investigations with at least one killer on the loose pushes the young officer and her tiny staff to their limits. Can Piper catch the murderer, or will the summer's body count continue to rise?