Case 125
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.
Lane
“Either Parker or Frankie is guilty.”
Parker
“Either Lane or Frankie is guilty.”
Frankie
“Reese is innocent.”
Peyton
“Parker and Frankie are both innocent.”
Reese
“Frankie 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.