The story goes something like ...

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> A few days after his wedding, a man disappeared without a trace. Many years later, a mysterious man showed up back in town, claiming to be him. He looked different, but he revealed to "his" wife all sorts of private details that presumably only her husband would know. The rabbi took him to the shul and asked him to identify where he used to sit, and he couldn't. The rabbi concluded that this fellow was a charlatan who'd found out all sorts of material about the real husband, but as a crook, never thought to ask about his ritual habits.
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I've heard several different names of who was the rabbi in this story. What have you heard, and does anyone have a source?