A wealthy merchant was found dead in his study during a torrential downpour. His pockets contained a wet wallet, soggy receipts, and a dry postage stamp glued tightly to an unmailed envelope on his desk. Detective Drake noted that the stamp proved the letter was never licked by the merchant that morning. Why?
The stamp was dry despite the room being humid from the storm, or more simply, if it rained heavily and windows were open, everything would be wet. Wait: a self-adhesive stamp doesn't need licking, but traditional stamps do. If it was a traditional stamp and the merchant was found dead before noon, why is the stamp dry in a humid room? Actually, if the stamp was dry while everything else was soggy, it hadn't been licked or exposed to moisture.
A stamp that requires moisture to stick would show signs of dampness if handled in a high-humidity environment or licked, unless it was applied dry later.
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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