Case 116
The Missing File
A signed contract file vanished from the archive.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Jules
“Kai is innocent.”
Casey
“Jules and Kai are both innocent.”
Alex
“Jules is innocent.”
Kendall
“Alex is guilty.”
Kai
“Neither Jules nor Alex is guilty.”
Who is guilty?
Solution: Kendall
If Kendall is guilty, Kendall's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.