"Well, what have you got to tell me?" he asked, when we were alone together in Julius Felborn's decorative private office.
"I've nothing to tell you," I said. "Nevertheless, I believe you will hear something if you've done as I suggested. Have you got the key or the combination of that big safe in the wall behind the desk?"
"I have the combination for to-day. Felborn was at the club last night when your letter came, and I asked him for it. There aren't many favours he wouldn't grant me. But what has Julius Felborn's safe to do with the case?"
"Please open it. We haven't much time to spare." I looked at my watch. In a quarter of an hour the Misses Callender ought to be announced. If they failed me after all—but I would not think of that "if."
Odell manipulated the combination, and the door of the safe swung open. I saw that there was room for a man inside, and explained to Odell that he must be the man. "It's absolutely necessary for you to hear for yourself," I insisted, "all that's said in this room during the next half-hour. If you didn't hear with your own ears, you'd never believe, and nothing would be said if you were known to be listening."
"You want me to eavesdrop!" he exclaimed, ready to be scornful.
"Yes," I admitted. "If you can call it eavesdropping to learn how and by whom Perry and Ned Callender Graham were done to death."
Without another word Odell stepped into the safe.
"With the door ajar you can hear every word spoken in this room," I said. "In a few minutes you'll recognise two voices—those of Miss Grace and Miss Marian Callender. I tell you this that you mayn't be surprised into making an indiscreet appearance. Remember your future's at stake and that of the girl you love. All you have to do is to keep still until the moment when the mystery is cleared up."
"How can it be cleared up by either of those two?" Odell challenged me, anger smouldering in his eyes.