“The door would have to be almost half open,” he reported, “for anyone in the corridor to be able to see the cup where Gerald put it. You’re sure you didn’t leave it that far open, Gerald?”
“Positive,” was the reply. “I may not have latched it, but——”
“Hold on a minute,” Dan interrupted. “The window at the end of the corridor was open at the top this afternoon. I remember that because it was so blamed cold when we came up before supper.”
“What do you mean?” asked Alf. “That some one might have got in that window?”
“Of course not! I mean that if there was a draft in the hall this door might have blown open if Gerald didn’t latch it as he went out.”
“That’s so. How was it when you came back?”
“Closed,” answered Dan promptly.
“Shut tight,” agreed Gerald.
“Looks, then, as though some one might have been in,” said Tom.