A rare emerald went missing from a high-security gallery. Three suspects were on duty: the guard who stood by the east entrance, the custodian who was sweeping the central hall, and the curator who was cataloging books in the west study. Each person had an alibi: the guard claimed he never left his post, the custodian said he swept every inch of the marble floor, and the curator stated she never looked up from her heavy ledger. Detective Vance surveyed the room and arrested the culprit instantly. Who took the emerald, and how did Vance know?
The custodian.
The custodian claimed to have swept every inch of the marble floor. However, a polished marble floor does not produce sweeping debris or dust that requires constant cleaning away from a specific path, but more importantly, he would have had to walk across the room, invalidating the guard's or curator's restricted sightlines, or his claim of sweeping 'every inch' would mean he swept under the display case before it was opened—which is impossible unless he had access.
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: Medium. More like this: Detective riddles with answers or try Truth & Lie Island for a different kind of puzzle.
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