Caught in Lies

A shot rings through the forest, and an old man falls. While on a bicycle ride, the narrator hears the blast from the gun. She hides, fearful the gunman might see her, and calls Mahoney. The hunt for the murderer begins. The investigation leads Detective Mahoney and the narrator across the county to a college town in New York to uncover the true identity of two young men, one of whom has suspiciously shown up in Cedar Falls on the heels on Homer Hunter's murder and claims to be his nephew.
Mahoney believes that one or both of them could be responsible for killing Homer and hiding his body in the woods. But a crank call from a mentally disturbed youth could also lead them to the murderer. Did he convert into action his belief that old people are useless and should die?