Case 058
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.
Frankie
“Lane is innocent.”
Lane
“Neither Frankie nor Kendall is guilty.”
Kendall
“Either Avery or Morgan is guilty.”
Avery
“Frankie is innocent.”
Morgan
“Either Frankie or Kendall is guilty.”
Who is guilty?
Solution: Morgan
If Morgan is guilty, Morgan's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.