letter I had put together for him.

"When did you show him this letter?" interrupted McKelvie.

"In the morning after Lee left the study. Mr. Darwin told me to patch it together because he said it would come in handy some day. It did--that night," and he leered at me in a very unpleasant way.

"Go on," said McKelvie peremptorily.

"I couldn't hear what they said----"

"Then how did you know that they were quarreling about the letter?" I asked.

"I was going to say," Orton ignored me completely, "that I couldn't hear the words exchanged until I opened the door a crack. Then I heard very well, indeed. Mr. Darwin was threatening Mr. Davies, and Mrs. Darwin retorted that she would send for him and warn him, but he only laughed in a queer way and then I saw her coming, so I retreated. After that he called me in and told me to watch her. I crept upstairs and heard her orders to the maid, whom I followed to the garage. Then I came back and hung around the hall. Mr. Darwin had told me he was expecting a visitor, so when I came back I applied my ear to the door. I could hear voices, his and a strange one, but not what they said, though they spoke loudly as if in anger."

"Why didn't you open the door a crack?" I inquired sarcastically.

"Because I was too clever. Mr. Darwin had locked the door when I went out and I knew it was still locked. Besides at ten-thirty only the lamp was lighted and the region of the door was in comparative darkness, but at this particular time I could tell by applying my eye to the key-hole that the other lights had been turned on as well. So even if I could have opened the door I should still have been afraid of being seen."

"Never mind that. Go on with what's important," broke in McKelvie, impatiently.

"At eleven-twenty-five Mr. Davies arrived, and at eleven-thirty Mr. Darwin called me."

"How?"

"There's a bell connection between the study and my workroom. When I went in Mr. Darwin had resumed his seat at the table and looked pretty much as he did when we saw him later, except he was alive."

"A good deal of difference, I should judge," I thought to myself, "between a corpse and a well man. However, that's neither here nor there."

"He had just finished writing the name, Cora Manning, on his new will, for the ink was not yet dry when I reached the table. I told him all that had taken place. It was then he laughed and said: 'So we've a broker in the house, eh? He should know how to play fast and loose, eh? I'll make him useful, this broker lover of our stainless Ruth.'"

Orton mouthed the words with devilish delight and I had all I could do to keep my hands off of him. But McKelvie paid no heed to our feelings.

"Go on, man," he said with growing impatience. "Don't repeat what I know already."

"You said that you wanted to hear everything that was spoken," grumbled Orton.

"Yes, so I did. Only hustle along and get it out. Was that all he said?" demanded McKelvie.

"No. He said something else. I remarked that a broker ought to know how to play fast and loose, and he replied: 'Yes, and other things, too, eh? Mr. Davies doesn't know it yet, but he has done me the very greatest service by coming here to-night. See that the windows are properly locked and then go to bed.' As I locked the windows I could hear him laughing to himself, and he was still laughing when I closed the door behind me."

"What did you think he meant to convey by those words of his?" asked McKelvie.

"I thought he might be referring to the fact that now he had good grounds for divorce. I believe he was tired of Mrs. Darwin," replied Orton.

"You are sure that Mr. Darwin was alone at eleven-thirty?" continued McKelvie, after a slight pause.

"Yes, absolutely alone," responded Orton. "There was no place where anyone could hide. I examined the window hangings as I locked up."

"What about the safe?"

"It was partly open and I looked in as I passed. It was empty."

"Humph. Now I'd have sworn--" murmured McKelvie.

"What?" asked Orton inquisitively.

"Nothing. What's the rest of your story?" retorted McKelvie.

"I didn't go to bed. I wanted to see what would happen, for I was sure from the way he spoke that Mr. Darwin meant to call Mr. Davies into the study later on, so I continued to work in the little room until I grew weary and thirsty, and going out in the hall found that it was about ten minutes to twelve. Still nothing had happened, for I could hear the murmur of voices in the drawing-room."

He didn't have to tell us how he knew. We could guess. Ruth was right in saying that he was always spying upon her.

"I knew," he continued, "that Mr. Darwin kept a good brand of whisky, private stock of course, in a cabinet in the dining-room, and I determined to mix myself a drink. But just then I heard the key turned in the study door and thinking Mr. Darwin was coming out, I went back to my room and closed the door. I waited some time, maybe five minutes or more, and then looked out. No one was around and both drawing-room and study doors were closed. I decided I had missed the show, since there was no sound from either room, and I determined to have my drink before I went upstairs. I went in to the dining-room and had my hand on the cabinet key when the shot rang out. I hurried to the study and saw--Mr. Davies in the doorway, Mrs. Darwin holding the pistol, and Mr. Darwin dead."

"You didn't see Mrs. Darwin go into the study?" questioned McKelvie.

"No, but I judged she had gone in when I heard the study door unlock. You see, I did not know what might happen, especially when Mr. Davies said I had no proof that I wasn't in the study also, so I decided to have an alibi for the police. That's why I said I was on the stairs because then they would not know where I had really been. I didn't know that Mrs. Darwin had seen me."

"A good thing for you that she did see you," returned McKelvie grimly, "or you might be occupying that cell in her place."

Orton blanched like the coward that he was. "But--but, I'm innocent," he said, indignantly.

"Well, you wouldn't be the first innocent person to grace a cell, I assure you," retorted McKelvie dryly. "You have told us everything?"

"Yes, everything."

"Very well, then you can answer several questions. You are positive you heard the key turned in the study door when you stood in the hall at ten minutes to twelve?" continued McKelvie. "Remember I want facts, and not impressions."

"I am as positive as that I am sitting here. But it was more toward five minutes to twelve because I paused to ascertain if Mrs. Darwin was still in the drawing-room and I listened for a minute or two before I started for the dining-room," replied Orton with conviction.

"A minute is a good long while, longer than you think, Orton," returned McKelvie. "But that point is, after all, immaterial. We will say that somewhere between ten and five minutes to twelve the study door was unlocked from the inside," and he looked at me significantly.

If he was right in his premise, then the person who unlocked that door could have been none other than the criminal, for at ten minutes before midnight Philip Darwin was past unlocking doors! Yet it seemed a foolhardy thing to do, for any one then could have entered and discovered him. But, no, after all, it was the sensible thing to do from his point of view, since otherwise the prospective suspect would have been unable to enter the room. Then I looked at McKelvie with dawning horror in my eyes. The unlocking of that door could have meant only one thing, that the criminal knew Ruth was across the hall, and deliberately, cold-bloodedly, planned to saddle her with the murder of her husband!

"Why, McKelvie," I began, horrified, but he tread on my toe as if by accident, and I recalled hastily that we were not alone.

"Even if I had not heard Mr. Darwin unlock the door," continued Orton ingratiatingly, "he must have unlocked it at some time, for I heard him turn the key in the lock when I left him at eleven-thirty and the door was open when Mrs. Darwin entered the room. But, I know I'm not mistaken in saying that I heard it unlocked."

"How do you know that it was Mr. Darwin who unlocked it?" I asked injudiciously.

McKelvie frowned, but Orton answered without apparent suspicion, "He was alone in a closed room. Who else could have opened it, Mr. Davies?"

"No one, of course," I lied cheerfully, and subsided into the background, not wishing to give Orton any further inkling of what we knew.

"When you came out into the hall the second time, you said that you heard no sound from either room. Did you open the study door even a crack that time by any chance?" resumed McKelvie.

"No. Again I feared to be seen. You see that all the lights in the room had been turned on," replied Orton.