Jones grinned. "I'll be hanged if I know," he replied. "But then we have not answered all the questions, you know. There's the motive and that second bullet. Oh, I say, McKelvie, what about letting me get busy on the trail of the revolver that made that second shot? There's a good substantial clue for you, though I know your preference for deductions."
McKelvie turned away from the window laughing at Jones' irony, then said quietly, "I won't trouble you to locate it as it might inconvenience you sadly. You see, I know where it is."
"You do?" Jones looked incredulous. "You know where it is and you haven't produced it?"
"How could I when you have had it under lock and key at Headquarters right from the start," returned McKelvie, his eyes twinkling.
"I? Oh, no, you're wrong there. I have only Darwin's pistol," replied Jones.
"That's the one I refer to."
"But, man, there's only one shot fired from that, the shot that killed Darwin," expostulated Jones.
"Use your imagination, Jones. Did you never hear of a man's cleaning his pistol and recharging it?" inquired McKelvie sarcastically.
"By Jove," said Jones, then added quickly, "What about the second bullet, then? I don't happen to possess that, too, do I?"
"No, for there was no second bullet."