‘There was hardly a breath of air as we sat on the terrace enjoying tea,’ reminisced Professor Fordney. ‘Rocca excused himself, saying he wished to telephone. Shortly after he entered the house, we heard a shot. I rushed into the drawing-room and found Rocca, smoking gun in hand, staring dumbly at the chair in front of the open window which held the huddled body of Chase.
‘A hasty examination disclosed the telephone receiver off the hook, a single cigarette stub of Rocca’s brand in the ash-tray, a bullet-hole in the gauze curtain six inches below the window-sill, and Rocca’s open cigarette-case in Chase’s lap. His replies to my hastily put questions were evasive. Inspector Kelley arrived while I was talking and took up the questioning.’
‘“Did you use the telephone?”
‘“Yes.”
‘“You came directly to this room and did not leave it?”
‘“Yes.”
‘“Chase was engaged to your sister?”
‘“Yes, he was.”
‘“Did you offer Chase a cigarette?”
‘“I did.”
‘“How did that dent get in your cigarette-case?”
‘“I dropped it about a week ago.”
‘“Did you shoot Chase?”
‘“I refuse to answer that question.”
‘At this point the doctor arrived and located the bullet in Chase’s body. Rocca then admitted Chase had been shot with the gun found in his own hand, but stubbornly refused to say anything more.
‘“What’s your opinion, Professor?” Kelley asked.
‘“Well,” I replied, “Rocca is obviously shielding someone. We have positive proof he came directly here and has not left this room. That, combined with the other evidence discovered, absolutely exonerates Rocca."’
How did the Professor know Rocca had not shot Chase?
