Case 360
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.
Riley
“Logan is guilty.”
Reese
“Finley is innocent.”
Finley
“Reese and Logan are both innocent.”
Logan
“Neither Finley nor Elliot is guilty.”
Elliot
“Either Riley or Logan is guilty.”
Who is guilty?
Solution: Riley
If Riley is guilty, Riley's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.