Case 305
The Stolen Watch
A valuable watch disappeared during a private gathering.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Kai
“Noah is guilty.”
Emery
“Noah and Riley are both innocent.”
Noah
“Elliot is innocent.”
Riley
“Neither Emery nor Noah is guilty.”
Elliot
“Emery and Noah are both innocent.”
Who is guilty?
Solution: Kai
If Kai is guilty, Kai's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.