The following text is from a fictional mystery story. Jonah is investigating strange events at an old country house.
At midnight, a book toppled from the library shelf, and the door slammed shut. The other guests hurried away, whispering about the ghost said to haunt the room. Jonah remained behind. Near the shelf, he found a thin thread running from the fallen book to the door. He also noticed damp soil on the carpet beneath an open window. “Someone wanted this to look like the work of a ghost,” he said. Before questioning the guests, Jonah decided to examine their shoes for traces of soil.
Which choice best describes Jonah’s response to the strange events?