"It was odd. I'll have to start somebody on his trail at once. Did you know that he was here the night of the murder?"
"Here in the house?" I gasped.
"No. Outside the study window," he returned.
"But McKelvie," I answered, thinking to trip him, "that footprint was made by Lee Darwin in leaving the study."
"What footprint?" He stared at me in evident surprise.
"I understood you to mean that you had deduced Lee's presence from the footprint that Jones discovered," I returned abashed.
He laughed heartily. "My dear man, where are your reasoning powers? Footprints don't last forever and we have had a shower since the murder. Besides I'm not clairvoyant enough to guess by a look at the imprint whose shoe made it. No, I base my deduction on this."
He held up a stick-pin of a peculiar dull brown hue, made in the shape of the head of a bulldog. On the gold setting around the base of the head had been engraved the name, L. Darwin.
"Where did you find it?" I asked eagerly, as he slipped it into his wallet.
"Beneath the first two windows of the study the ivy has grown very thickly. I found the pin close to the wall and directly beneath the second window, entangled in the vine. The head is exactly the color of the ivy stem and it had remained unnoticed. I saw it because I was hoping to find proof of his presence there."