Case 170
The Disabled Camera
A security camera was deliberately switched off.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Parker
“Alex is innocent.”
Frankie
“Alex and Casey are both innocent.”
Taylor
“Parker is guilty.”
Alex
“Frankie is innocent.”
Casey
“Neither Parker nor Alex is guilty.”
Who is guilty?
Solution: Taylor
If Taylor is guilty, Taylor's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.