In the kingdom of ingenuity someone stole the crown of the prince who was about to be crowned king. The soldiers arrested three suspects among whom was the only one guilty of the robbery. They were brought before the prince and it happened that the first immediately accused the second of the robbery. The proceedings of the trial do not include the statements of the second or third suspect, but we are told that Prince Justiniano discovered the culprit since he was the only one who told the truth.
Which of the three suspects was to blame for the theft?
As we are told that the culprit was the only one to tell the truth, he cannot be the first suspect since having told the truth he would have accused himself. The second suspect cannot be guilty either since then the first would have told the truth which contradicts the fact that the culprit is the only one who tells the truth. So that,
the culprit was the third suspect.