as much light as possible on this point. Hence the need of M. Gritz.

M. Herman Gritz was a short, massive man with hard, puffy eyes and thin
black hair, rather curly and oily, and a rapacious nose. He appeared
(having been induced to come down by the commissary) in a richly
embroidered blue-silk house garment, and his efforts at affability were
obviously based on apprehension.

Coquenil began at once with questions about private room Number Seven. We
had reserved this room and what had prevented the person from occupying it?
M. Gritz replied that Number Seven had been engaged some days before by an
old client, who, at the last moment, had sent a _petit bleu_ to say that he
had changed his plans and would not require the room. The _petit bleu_ did
not arrive until after the crime was discovered, so the room remained
empty. More than that, the door was locked.

"Locked on the outside?"

"Yes."

"With the key in the lock?"

"Yes."

"Then anyone coming along the corridor might have turned the key and
entered Number Seven?"

"It is possible," admitted M. Gritz, "but very improbable. The room was
dark, and an ordinary person seeing a door locked and a room dark----"