Case 157
The Missing File
A signed contract file vanished from the archive.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Marley
“Sam is innocent.”
Sam
“Noah is innocent.”
Frankie
“Either Sam or Blake is guilty.”
Blake
“Marley and Noah are both innocent.”
Noah
“Either Sam or Frankie is guilty.”
Who is guilty?
Solution: Frankie
If Frankie is guilty, Frankie's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.