Case 009
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.
Lane
“Peyton is innocent.”
Morgan
“Neither Lane nor Dakota is guilty.”
Alex
“Either Morgan or Dakota is guilty.”
Dakota
“Lane and Peyton are both innocent.”
Peyton
“Alex is guilty.”
Who is guilty?
Solution: Alex
If Alex is guilty, Alex's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.