Therefore I exclaimed suddenly:

"Will you not tell me, Mrs. Petre, the ident.i.ty of this great enemy of our friend--this woman? Upon information which you yourself may give, Digby's future entirely depends," I added earnestly.

"His future!" she echoed. "What do you mean?"

"I mean only that I am trying to clear his good name of the stigma now resting upon it."

The handsome woman bit her lip.

"No," she replied with a great effort. "I'm sorry--deeply sorry--but I am now in a most embarra.s.sing position. I have made a vow to him, and that vow I cannot break without first obtaining his permission. I am upon my honour."

I was silent. What could I say?

This woman certainly knew something--something which, if revealed, would place me in possession of the truth of what had actually occurred at Harrington Gardens on that fatal night. If she spoke she might clear Phrida of all suspicion.

Suddenly, after a pause, I made up my mind to try and clear up one point--that serious, crucial point which had for days so obsessed me.

"Mrs. Petre," I said, "I wonder if you will answer me a single question, one which does not really affect the situation much. Indeed, as we are, I hope, friends, I ask it more out of curiosity than anything else."

"Well, what is it?" she asked, regarding me strangely.

"I want to know whether, being a friend of Digby's, you have ever met or ever heard of a certain young lady living in Kensington named Phrida Shand."

The effect of my words was almost electrical. She sprung towards me, with fire in her big, dark eyes.

"Phrida Shand!" she cried wildly, her white-gloved hands again clenched.

"Phrida Shand! You know that woman, eh? You know her, Mr. Royle. Is she a friend of yours?--or--or is she your enemy? Your friend, perhaps, because she is pretty. Oh, yes!" she laughed, hysterically. "Oh, yes! Of course, she is your friend. If she is--then curse her, Mr. Royle--invoke all the curses of h.e.l.l upon her, as she so richly deserves!"

And from her lips came a peal of laughter that was little short of demoniacal, while I stood glaring at her in blank dismay.

What did she mean? Aye, what, indeed?

CHAPTER XI.

IN WHICH AN ALLEGATION IS MADE.

I stood aghast at her words.

I strove to induce her to speak more openly, and to tell me why I should not regard Phrida as my friend.

But she only laughed mysteriously, saying:

"Wait, and you will see."

"You make a distinct charge against her, therefore I think you ought to substantiate it," I said in a tone of distinct annoyance.

"Ah! Mr. Royle. Heed my words, I beg of you."

"But, tell me, is Miss Shand the same person as you have denounced as Digby's enemy?" I asked in breathless apprehension. "Surely you will tell me, Mrs. Petre, now that we are friends."

"Ah! but are we friends?" she asked, looking at me strangely beneath the light of the street-lamp in that deserted thoroughfare, where all was silence save the distant hum of the traffic. The dark trees above stood out distinct against the dull red night-glare of London, as the mysterious woman stood before me uttering that query.

"Because we are mutual friends of Sir Digby's. I hope I may call you a friend," I replied, as calmly as I was able.

She paused for a moment in indecision. Then she said:

"You admit that you are friendly with the girl Shand--eh?"

"Certainly."

"More than friendly, I wonder?" she asked in a sharp tone.

"Well--I'll be perfectly frank," was my answer. "I am engaged to be married to her."

"Married," she gasped, "to her! Are you mad, Mr. Royle?"

"I think not," I answered, greatly surprised at her sudden att.i.tude.

"Why?"

"Because--because," she replied in a low, earnest voice, scarce above a whisper, "because, before you take such a step make further inquiry."

"Inquiry about what?" I demanded.

"About--well, about what has occurred at Harrington Gardens."

"Then you know!" I cried. "You know the truth, Mrs. Petre?"

"No," she replied quite calmly. "I know from this letter what must have occurred there. But who killed the girl I cannot say."

"Who was the girl they found dead?" I asked breathlessly.

"Ah! How can I tell? I did not see her."

In a few quick words I described the deceased, but either she did not recognise her from the description, or she refused to tell me. In any case, she declared herself in ignorance.

The situation was galling and tantalising. I was so near discovering the truth, and yet my inquiries had only plunged me more deeply into a quagmire of suspicion and horror. The more I tried to extricate myself the deeper I sank.

"But whoever the poor girl may have been, you still maintain that Phrida Shand was Digby's most deadly enemy?" I asked quickly, setting a trap for her.

I took her unawares, and she fell into it.

"Yes," was her prompt response. An instant later, however, realising how she had been led to make an allegation which she had not intended, she hastened to correct herself, saying: "Ah, no! Of course, I do not allege that. I--I only know that Digby was acquainted with her, and that----"

"Well?" I asked slowly, when she paused.