Case 004
The Swapped Envelope
A sealed envelope was replaced with an empty one.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Kendall
“Blake and Logan are both innocent.”
Harper
“Either Dakota or Logan is guilty.”
Dakota
“Neither Blake nor Logan is guilty.”
Blake
“Neither Dakota nor Logan is guilty.”
Logan
“Kendall and Dakota are both innocent.”
Who is guilty?
Solution: Harper
If Harper is guilty, Harper's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.