She hesitated a moment, then in a low, eager voice she said:
"Because I have already seen that three-edged knife in another person's possession."
"That's pretty strong evidence," I declared. "The person in question will have to prove that he was not in Rannoch Wood last evening at nightfall."
"How do you know it was done at nightfall?" she asked quickly with some surprise, half-rising from her chair.
"I merely surmised that it was," I responded, inwardly blaming myself for my ill-timed admission.
"Ah!" she said with a slight sigh, "there is more mystery in this affair than we have yet discovered, Mr. Gregg. What, I wonder, brought the unfortunate young man up into our wood?"
"An appointment, without a doubt. But with whom?"
She shook her head, saying:
"My father often goes to that spot to shoot pigeon in the evening. He told us so at luncheon to-day. How fortunate he was not there last night, or he might be suspected."
"Yes," I said. "It is a very fortunate circumstance, for it cannot be a pleasant experience to be under suspicion of being an assassin. He was at home last night, was he?" I added casually.