A rare emerald went missing from a locked display case. Three guards were on duty: Guard A stood by the north door, Guard B by the south, and Guard C by the east. Guard A swore he saw Guard B blink twice. Guard B said Guard C was holding a flashlight. Guard C claimed Guard A was asleep. Only one statement was true. Who stole the emerald?
Guard A
If Guard A is telling the truth, Guard B blinked (possible), making B's statement false (holding a flashlight), making C's statement false (A was asleep), which contradicts A telling the truth. Wait, let's test Guard B: B says C held a flashlight. If B is true, C is false (A wasn't asleep). If C is false, A's statement (B blinked twice) is false. This works! If B is true, A lied, so B didn't blink. Thus, Guard B is honest, meaning Guard A lied (was asleep), and Guard C lied. Therefore, Guard A abandoned his post to steal the gem.
About this riddle
Detective riddles are tiny mysteries. Look for the detail in the story that does not fit; it is usually the clue that solves the case.
Difficulty: Hard. More like this: Detective riddles with answers or try Truth & Lie Island for a different kind of puzzle.
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