Case 285
The Lost Access Card
A master access card was taken from the reception desk.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Morgan
“Marley is guilty.”
Marley
“Casey is innocent.”
Logan
“Neither Noah nor Casey is guilty.”
Noah
“Logan and Casey are both innocent.”
Casey
“Either Morgan or Noah 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.