Final answer:
A neighbor reported hearing a shriek in the night, raising suspicions of foul play.
Step-by-step explanation:
The neighbor reported hearing a shriek in the night, leading to suspicions of foul play. In the passage, John heard a faint far-away sound followed by a sharp noise just outside his room, which caused him to feel a sense of unease. Additionally, the text mentions other sounds heard during the night, such as the croaking of frogs, the whispering sound of wind, and the cry of a solitary whippoorwill, but it was the sound of a shriek that raised suspicions of foul play.