Case 140
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.
Avery
“Either Finley or Blake is guilty.”
Sam
“Either Cameron or Finley is guilty.”
Cameron
“Sam and Blake are both innocent.”
Finley
“Cameron is guilty.”
Blake
“Cameron is innocent.”
Who is guilty?
Solution: Finley
If Finley is guilty, Finley's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.