“To find out how the murderer got away from the library last night. If we can solve that little problem, we’ve cleared up the last remaining difficulty as far as the committing of the murder goes.”
“Yes, I suppose we have,” Alec replied thoughtfully. “But it seems to me that we’ve rather got our work cut out there, haven’t we? I mean, it’s pretty well impossible for a man to get out of a room like that and leave everything locked up behind him, you know.”
“On the contrary, that’s just what it isn’t; because he did it. And it’s up to us to find out how.”
“Got any ideas about it?” Alec asked with interest.
“Not a one! At least, I can think of one very obvious way. We’ll test that first, at any rate. The library’s empty now, and I expect Jefferson will be pretty busy for the rest of the afternoon. We can sleuth away in peace.”
They turned their steps in the direction of the library.
“And what is the obvious solution to the library mystery?” Alec asked. “I’m blessed if I can see one.”
Roger looked at him curiously. “Can’t you really?” he said.
“No, I’m dashed if I can.”
“Well—what about a secret door, then?”