Case 061
The Stolen Watch
A valuable watch disappeared during a private gathering.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Alex
“Lane is innocent.”
Riley
“Alex is innocent.”
Lane
“Jules is guilty.”
Taylor
“Neither Alex nor Lane is guilty.”
Jules
“Taylor is guilty.”
Who is guilty?
Solution: Jules
If Jules is guilty, Jules's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.