Case 251
The Stolen Prototype
A prototype vanished from a secured workroom.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Frankie
“Blake is innocent.”
Drew
“Neither Frankie nor Emery is guilty.”
Sam
“Either Drew or Blake is guilty.”
Blake
“Sam is guilty.”
Emery
“Frankie and Drew are both innocent.”
Who is guilty?
Solution: Sam
If Sam is guilty, Sam's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.