Case 103
The Empty Safe
A small office safe was found empty in the morning.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Avery
“Either Morgan or Parker is guilty.”
Rowan
“Neither Morgan nor Elliot is guilty.”
Morgan
“Elliot and Parker are both innocent.”
Elliot
“Either Avery or Parker is guilty.”
Parker
“Avery is guilty.”
Who is guilty?
Solution: Avery
If Avery is guilty, Avery's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.