Case 327
The Missing Ledger
A confidential ledger disappeared from the office.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Drew
“Either Finley or Hayden is guilty.”
Finley
“Alex is innocent.”
Alex
“Finley and Hayden are both innocent.”
Riley
“Finley is innocent.”
Hayden
“Finley and Riley are both innocent.”
Who is guilty?
Solution: Drew
If Drew is guilty, Drew's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.