The Sterling Safe Deposit Company! Well, at last I had some definite information! At last I had something to work upon! I went at once to the deposit company, and asked for an interview with the manager. I had difficulty in persuading him to grant my request, but after realizing the gravity of the situation and the significance of the clue, he told me that that key belonged to a safe deposit box rented by a Mrs. Altonstall, who lived on West Fifty-eighth Street.

I looked at my watch. It was almost five o'clock, but I concluded to go at once to call on the lady.

As I went up there in a taxicab, my brain was in a whirl. The key of a safe deposit box, not Mr. Pembroke's own, but belonging to a woman! found in his room, after a crime which it was assumed was committed by a woman!

Who was Mrs. Altonstall? And why should she murder Robert Pembroke? This question opened such a wide field for speculation that it was unanswerable. Had the deed really been done by a woman? And was I, even now, about to verify this?

I felt an uncertainty about proceeding. Ought I not to place the whole matter in the hands of the Coroner? Was I not taking too much upon myself to investigate alone this new evidence?

But, I reasoned, delay might be dangerous. If the Coroner were to postpone until next day an interview with this woman, might she not have already effected her escape? Was it not wiser that I should go there at once, and lose no time in securing any possible information?

At any rate, I went, resolved to take the consequences of my deed, whatever they might be.

The address given me proved to be a large and handsome apartment house. At the office I inquired for Mrs. Altonstall and being informed that she was at home, I sent up my card, for I judged that the most open and straightforward measures were the best.

A moment later I was informed that Mrs. Altonstall would see me, and entering the elevator I went at once to her apartment.

The general effects of grandeur throughout the house and the elegance of Mrs. Altonstall's own room, made me wonder afresh if I could by any possibility be on the track of a criminal. Surely, the criminal classes did not live in a style implying such respectability and aristocracy as these surroundings seemed to indicate. But of course I realized that a woman who could commit murder was not necessarily found among the criminal classes, and indeed, being an exceptional individual, might be looked for in any setting.

But when my hostess entered, and I saw a sweet-faced, middle-aged lady, of gentle manner and gracious mien, walk toward me, I felt the blood rush to my face, and I stood consumed with dismay and confusion.

"Mrs. Altonstall?" I said, conquering my embarrassment.

"Yes," she said, in one of the sweetest voices I ever heard. "This is Mr. Landon? you wanted to see me?"

Surely with such a queen of women as this, frankness and truth were the only lines to follow.

"Yes, Mrs. Altonstall," I said; "I am a lawyer, and I am at present investigating a serious case. In connection with it, there has been found a key, which I have been informed belongs to you. Will you kindly say if this is so?"

As I spoke, I handed her the key. I need not say that at the first glimpse of that serene, gracious face, all thought of her implication in our affair instantly vanished. Presumably, too, the key was not hers, there had been a mistake, somehow.

As she took the key, she looked at me with a bewildered surprise. "Why, yes, Mr. Landon," she said, "this is my key. May I ask where you obtained it?"

I hesitated, for it seemed a terrible thing to tell this queenly lady where her key had been found. And yet the situation was so inexplicable, that I must solve it if possible.

"I will tell you in a moment, Mrs. Altonstall," I said, slowly, "but first I must ask you if you know Mr. Robert Pembroke?"

"Robert Pembroke?" she repeated; "no, I never heard the name. Who is he?"

The unruffled calm and the straightforward gaze that met my own eyes, so frankly, was so convincing of her absolute veracity, that just for an instant the thought flashed through my mind that it might be merely the perfection of acting.

But the next instant I knew better, for no human being could so simulate utter ignorance of a subject, if she had guilty knowledge of it. Moreover, since she knew nothing of Robert Pembroke, I instantly concluded not to tell her of the tragedy, but to inquire further concerning the key.

"Since you do not know him, Mrs. Altonstall, let us not discuss him. Will you tell me how you lost possession of this key, since it is yours?"

"I gave it to my lawyer, Mr. Leroy," she replied. "It was necessary that he should get some of my papers from the Safe Deposit Company, and it has been arranged that he shall have access to my box on presentation of my key. I am a widow, Mr. Landon, and as I have various financial interests, it is necessary for me frequently to employ the services of a lawyer. Mr. Leroy attends to all such affairs for me."

"Do you mean Mr. Graham Leroy?" I asked, very gravely, for the introduction of his name stirred up all sorts of conjectures.

"Yes," she replied, "he is an able lawyer, as well as a kind friend."

"I'm acquainted with Mr. Leroy," I responded, "and I quite agree with your estimate of him. When did you give him the key, Mrs. Altonstall?"

"About four or five days ago; last Saturday, to be exact. There was no immediate haste about my papers, he was to attend to the matter at his convenience. May I ask where the key was found?"

I disliked extremely to rehearse the details of the case, and I knew it was in no way necessary. Of course the key belonged to this lady; aside from her own word, the bank had told me so. But her question must be answered.

"It was found in the apartment of Mr. Robert Pembroke," I said; but immediately added, as she looked slightly startled, "I think, however, it is a matter of easy explanation. Graham Leroy is also Mr. Pembroke's lawyer, and he must have dropped the key there while calling on Mr. Pembroke."

"Unpardonable carelessness," she said, and I saw that the sweet placid face could assume an expression of indignation upon occasion.

"That, madam, you must say to Mr. Leroy. I am sorry to have troubled you in the matter, and I thank you for your courtesy to me."

"But you will leave my key with me?" she said, as I was about to take leave.

"I think I cannot do that, Mrs. Altonstall," I said, "as it was entrusted to me by official authority. But I promise to return it to Mr. Leroy, which, I trust will be satisfactory to you."

The lady agreed to this, though a little unwillingly, and I went away, newly perplexed at this most recent development.

So then, Graham Leroy had been in possession of this key. So then, he must have left it in Robert Pembroke's bedroom. He would not have done this purposely, of course, therefore he must have dropped it there without knowing it. It was found on Robert Pembroke's bed. Not under the pillow,—the suggestion that it had been under the pillow was mere supposition. It might have been dropped on the bed from the pocket of one leaning over the sleeping man.

But Graham Leroy! the thought was preposterous!

And then again, the old, ever insoluble question,—how could he get in?

But really it was scarcely more impossible to conclude how he got in, than to imagine Graham Leroy getting in at all, except in correct and ordinary fashion.

My brain worked quickly. To be sure, he might have dropped the key in that room when calling there, as he did, on Tuesday night.

But I had asked Charlotte when Mr. Pembroke's bedroom had last been swept, and she had told me that she had swept it Wednesday morning, and had then emptied the waste basket. This had seemed to me to prove that all the clues I had found, had been brought into the room after that sweeping. But again, the key being found in the bed it had nothing to do with the sweeping of the room. However, Charlotte could not have made up the bed without seeing the key, so the only possible deduction was that Mrs. Altonstall's key had been left in Robert Pembroke's room after noon of Wednesday, the day he was murdered!

It was all too much for me! I had undertaken to trace the clues that I had myself found, but if they were to lead me to such extraordinary discoveries as this, I felt I must appeal to more practical detective talent.

But Leroy or not, at any rate it turned the tide of suspicion away from Janet. This was joy enough, of itself, to compensate for any horrible revelation that might come in the future concerning Leroy or anyone else.

Somewhere in the back of my brain two dreadful words that the Coroner had used were hammering for admittance. These were connivance and complicity; if Leroy entered the apartment on Wednesday night at any hour he was let in by either Janet or Charlotte.

At that moment I realized the truth of the line, "that way madness lies."

I pushed the thought from my mind with all my will power, and hastening my steps, for I had walked from Fifty-eighth Street, I went rapidly homeward.

I reached home about six o'clock, and found that George Lawrence was there, and that Laura had invited him to stay to dinner. I was pleased at this, for I hoped that by the casual conversation at table I could learn something of Mr. Pembroke's past life and acquaintances.

I concluded to say nothing about my discoveries of the afternoon, but to advise them of my decision to continue my search for a real criminal; a housebreaker or burglar, who could have committed the crime for the money, which he stole, and who must have contrived some way to get in through a window.

During dinner, although Laura endeavored to keep away from the all-engrossing subject, which she disapproved of as table conversation, I gave a slight outline of the effort I intended to make.

George Lawrence seemed greatly pleased with my ideas. He agreed that there must be some one, somewhere, besides himself and Janet who could be shown to have a motive, and he offered to assist me in looking over his uncle's private papers for some letter or other evidence which might indicate this.

"Simply to make a statement of the case, but for no other reason," said George, "I will agree with you that the facts, as known, seem to implicate Janet. But as she is utterly incapable of such a thing, and as the idea of Charlotte being involved in the matter is absurd, the criminal must be somebody else, and we must find him or her. I say 'him or her' because the inspector declares that the hat-pin indicates a woman's deed, and, as we are utterly at sea regarding the individuality of the criminal, we are, I think, justified in assuming either sex. It is, of course, not beyond the bounds of possibility that Uncle Robert had a feminine enemy."

"Once we can establish a motive," I said, "we shall have something to work upon in our hunt for evidence."

"And yet motive isn't everything," said Lawrence, with a grim smile; "for if Janet had a motive, as you say, an equal one must be attributed to me, as I am an equal inheritor of Uncle Robert's fortune."

I looked wonderingly at the young man. "The motive attributed to Miss Pembroke," I said "would probably not be her desire for inheritance, so much as the desperate difficulties attending her life with her uncle."

This seemed to surprise Lawrence, but he only said carelessly: "It doesn't matter what motive they assign to Janet, for she didn't have any motive, and she didn't do the deed. But, for the moment, I'm speaking not of facts or even possibilities, but of contingencies which might arise. It might be claimed that I had a motive, from the mere fact that I am one of my uncle's heirs."

"But you couldn't get in, George," said Janet quickly. "Your latch-key was of no use when the chain was on."

"That's true enough, Janet, and we all know it; but, as I say, we're speaking of a hypothetical case. And you know, if we're going to hunt for some other person with a motive, we're bound to admit that he got into the apartment somehow. Therefore, to eliminate the possibility of being myself a suspect, I'll merely state, as a matter of fact, that my alibi is perfect. I can prove, should it be necessary, that I was far away from Sixty-second Street at the time of Uncle Robert's death, and can account for my time all through the night."

I liked Lawrence's way of putting these things, and began to think his clear-headed views on the matter would be of assistance to me, even though he had no taste or talent for detective work.

"Just what is an alibi?" asked Janet, with a perplexed air.

"It means," I answered, "proof by witnesses of a person's whereabouts at a given time."

"Oh!" said Janet. "And where were you last night, George?"

Lawrence smiled as he answered: "I'm not in the witness box now, Janet, but I don't mind telling you that I dined and spent the evening at the Warings'."

"Oh, did you?" cried Janet. "And you took Milly to a matinÉe in the afternoon. I know, because she told me about it before. You're getting awfully fond of her, aren't you, George?"

"Yes, I like Miss Waring extremely," said Lawrence, and though he spoke as if he meant it, a certain sadness came into his eyes, and I suspected that Miss Waring did not reciprocate his regard.

But though the young man seemed suddenly distrait, and did not attempt to continue our previous conversation, Janet, on the contrary had brightened up wonderfully. Being in a mood for making inferences, I deduced that George Lawrence was more interested in Miss Waring than Janet desired him to be, and that she was pleased rather than otherwise at George's lack of enthusiasm about the lady. Thereupon the sudden fear that Janet was in love with her cousin assailed me. This aroused what was of course an unreasonable jealousy on my part, for I had not the slightest actual foundation on which to rest the hopes I was rapidly building. I eagerly watched the two cousins after that, to discover if there was anything more than cousinly affection on either side.