Go on, I said.
Well, I have received personal information from a source high in society that a very important document has been stolen from the royal apartments.
The thief is known without a doubt because he was seen taking it.
It is also known that the document remains in his possession.
How is this known? Asked Dupin.
Because, replied the Captain,
If the thief were to use the document, certain events would come to pass. These events have not occurred, but the mere threat of them gives the thief power as long as the document is in his possession.