"Who knew that you were going to the Northumberland Hotel?" asked Holmes, glancing keenly across at our visitor.
"No one could have known. We only decided after I met Dr. Mortimer."
"But Dr. Mortimer was no doubt already stopping there?"
"No, I had been staying with a friend," said the doctor.
"There was no possible indication that we intended to go to this hotel."
"Hum! Someone seems to be very deeply interested in your movements." Out of the envelope he took a half-sheet of fools-cap paper folded into four.
This he opened and spread flat upon the table.
Across the middle of it a single sentence had been formed by the expedient of pasting printed words upon it. It ran:
As you value your life or your reason keep away from the moor.
The word "moor" only was printed in ink.