Case 242
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.
Noah
“Sam is guilty.”
Hayden
“Riley and Logan are both innocent.”
Riley
“Hayden and Sam are both innocent.”
Sam
“Logan is innocent.”
Logan
“Neither Hayden nor Sam is guilty.”
Who is guilty?
Solution: Noah
If Noah is guilty, Noah's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.