Case 165
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.
Rowan
“Either Alex or Marley is guilty.”
Alex
“Either Blake or Marley is guilty.”
Lane
“Rowan is innocent.”
Blake
“Neither Rowan nor Lane is guilty.”
Marley
“Blake is guilty.”
Who is guilty?
Solution: Marley
If Marley is guilty, Marley's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.