Case 217
The Lost Access Card
A master access card was taken from the reception desk.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Frankie
“Neither Jules nor Reese is guilty.”
Lane
“Either Jules or Reese is guilty.”
Dakota
“Frankie and Reese are both innocent.”
Jules
“Frankie and Dakota are both innocent.”
Reese
“Dakota is innocent.”
Who is guilty?
Solution: Lane
If Lane is guilty, Lane's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.