Case 137
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.
Lane
“Neither Blake nor Casey is guilty.”
Blake
“Neither Lane nor Parker is guilty.”
Rowan
“Blake is guilty.”
Casey
“Rowan is guilty.”
Parker
“Lane is innocent.”
Who is guilty?
Solution: Rowan
If Rowan is guilty, Rowan's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.