As we drove toward Forty-second Street, I recalled my instinctive distrust of the secretary, his stealthy attitude, and very evident desire to see Ruth convicted. I had suspected him that very first night, and now I envisioned him sneaking through the secret entrance and returning to the house in time to follow me into the study.

"I know what you are thinking, but he couldn't possibly have done it," said McKelvie quietly. "He's the only one I don't suspect. He hasn't the nerve in the first place, and in the second place he hadn't the time. How long do you suppose it takes to lock all those doors—they were locked, remember—and return to the house and lock whatever entrance he used—not the front door, for you would have heard him—and enter the study a second after yourself?"

"He may never have gone out," I cried. "He could easily have stayed in the room all the time in a dark corner and have come forward when he turned on the lights. I swear I never heard him!"

"What about Mrs. Darwin's testimony that he was in the hall?" he asked.

"She may have been mistaken. He gave false evidence concerning her."

"That's what we are going to see him about. But, remember this, Mrs. Darwin would have no reason for saying she saw him if she did not."

To this last statement I had to agree, for Ruth I knew disliked Orton, and would hardly be likely to shield him. So I ceased discussing the point, knowing we would soon have the truth, for McKelvie could extract information from a stone.

In due course we drew up before a second-rate apartment hotel that was sadly in need of a coat of paint. We entered a dingy hall and inquired for Orton.

"Suite Four, third door to your left," droned the switchboard girl.

We walked down the hall, which would have been decidedly improved by an application of a mop and some soap and water, and knocked at Orton's apartment. As we waited we heard the sound of a door closing, and then the shuffle of feet and presently the door opened a crack and Orton's near-sighted eyes peered at us from the aperture.

"What do you want?" he asked impatiently.

"A moment's conversation," replied McKelvie, but at that minute Orton recognized me and, swiftly retreating, began to close the door.

McKelvie, however, was prepared for him and the closing door met an obstruction in the shape of the toe of McKelvie's boot.

"There is no use trying to keep me out," he continued sternly, "unless of course you would like to tell your story to the police."

At mention of the police Orton retreated still farther, and we followed him into the apartment, closing the door behind us. We found ourselves in a stuffy, gloomy little parlor filled with a lot of ugly, old-fashioned furniture. Orton, who was clad in dressing-gown and slippers, ungraciously asked us to be seated, but before we could state our errand a quavering voice from somewhere in the rear reached us.

"What is it, Claude? Who is in there with you?" it said.

"You have frightened my mother," said Orton, plucking at the cord of his wrapper, as if undecided whether to go or stay.

"Tell her it's all right and that you know who we are," commanded McKelvie. "And without leaving this room," as Orton started to move away. "I guess she can hear you from here."

Sullenly, Orton obeyed, and then seating himself on the sofa, demanded what we wanted.

"At the inquest you gave several bits of information which had no foundation in fact," began McKelvie, going straight to the point. "You lied and you know it. For that matter so do I. Now I want to know why?"

"Mr. Davies, of course I know," answered Orton with a sneer. "But what right have you to question me?"

"I am investigating the case for Mr. Davies on the quiet," answered McKelvie suavely.

"And that gives you the right to intrude on my privacy, I suppose?" continued Orton sarcastically (he had abandoned his rÔle of "humble still," or rather he was Uriah Heep grown bold through triumph), "and to force yourself into my rooms?"

McKelvie shrugged. "Really if you would rather be put through the third degree at Police Headquarters it's a matter of indifference to me."

Orton's pallid face became livid. "Are you trying to frighten me by pretending that you believe that I killed Philip Darwin?" he cried, but his voice trembled in spite of himself.

"No, I'm not pretending any such thing. I know you didn't kill him. You're too much of a coward," returned McKelvie contemptuously, whereat Orton gave a gasping sigh of relief. "But I do say you know more of this murder than you gave out, and a hint to that effect in the ear of Jones will be quite sufficient to bring the police to this place. No doubt you have a telephone that I can use. I'll give you five minutes to decide."

But Orton didn't need five minutes, no, nor even ten seconds. McKelvie had hardly finished speaking when Orton flung himself forward with clasped hands, his prominent eyes fairly popping with terror.

"I'll tell you everything, anything, though I declare I know nothing. Only don't send the police here," he pleaded in a frightened voice.

I was amazed at his abject fear but McKelvie motioned him back, and said coldly: "Very well, but don't lie to me, for I know why you fear the police." He leaned closer and whispered a word that I did not catch, but which had the effect of making Orton wring his hands helplessly, and whine that he never intended to lie, and would tell us everything we wanted to know.

McKelvie silenced him with a gesture, as he said: "I want an account, a true one, of everything that you did and said and saw on the night of October the seventh between ten-thirty, when you summoned Mrs. Darwin to the study and midnight, when the shot rang out."

"I wanted to tell what Mr. Darwin had said and they wouldn't let me at the inquest," put in Orton, aggrieved.

"You're not dealing with the police now, and I want every word that has any bearing on the case, whatever its purport."

"Very well. At ten-thirty I told Mrs. Darwin that her husband wanted her and then I listened at the door. They were quarreling about the love 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.