"I do not! But having committed the robbery, and then having discovered that this woman, who you say has blackmailed you, had actually taken an apartment in the same building with your affianced, you may have gone there to urge her to leave, and have killed her to save yourself."
"Plainly you do not know me. There is one point in what you say which is interesting. Did I understand that this woman had an apartment in the Thirtieth Street building."
"Certainly, and you knew it."
"You are mistaken. Let us return to the jewels. You think that these are the missing gems. If I prove to the contrary, will you agree not to place me under arrest?"
"With pleasure," said the detective, feeling safe in the idea that what Mr. Mitchel offered to do was an impossibility.
"Thank you. That gives me my freedom, in exchange for which courtesy I promise you all the assistance in my power in finding the murderer." Saying which Mr. Mitchel touched an electric-button and when it was answered sent a message up-stairs asking Mr. Charles to come down. In a few moments, that gentleman appeared.
"Mr. Charles," said Mr. Mitchel, "would it be possible for me to enter these vaults without your knowledge?"
"It would be impossible for any one to enter here without my knowledge," said Mr. Charles.
"You keep my key, do you not?"
"Yes, sir."