Case 168
The Vanished Key
A locked evidence cabinet was opened without permission.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Finley
“Jules and Quinn are both innocent.”
Cameron
“Neither Finley nor Quinn is guilty.”
Jules
“Either Finley or Logan is guilty.”
Quinn
“Finley and Cameron are both innocent.”
Logan
“Cameron is guilty.”
Who is guilty?
Solution: Logan
If Logan is guilty, Logan's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.