“But you can hardly be certain that a wretched crime in this comparatively insignificant quarter of London supplies the actual motive of Mr. Forbes’s action,” urged Theydon.

The girl stamped an impatient foot.  He heard it distinctly.

“Of course I am certain,” she cried.  “Why won’t you be candid?  You know I am right—­ I can tell it from your voice, and your guarded way of talking—­”

An inspiration came to Theydon’s relief in that instant.

“Pardon the interruption,” he said, “but I must point out that both of us are acting unwisely in discussing such matters over the telephone.  Really, neither must say another word, except this—­ when I have found your father I’ll ask his permission to come and see you.  Perhaps we three can arrange to meet somewhere for luncheon.  That is absolutely the farthest limit to which I dare go at this moment.”

“O, very well!”

The receiver was hung up in a temper, and the prompt ring-off jarred disagreeably in Theydon’s ear.  If he was puzzled before, he was thoroughly at sea now.  But he took a bold course, and cared not a jot whether or not it was a prudent one.

The mere sound of Evelyn Forbes’s voice had steeled his heart and conscience against the dictates of common sense.  Let the detectives think what they might, the girl’s father must be allowed to carry through his plans without let or hindrance.

“Miss Beale,” said Theydon, gazing fixedly into the sorrow-laden eyes of the quiet little lady whom he found seated where he had left her, “I’m going to tell you something very important, very serious, something so far-reaching and momentous that neither you nor I can measure its effect.  You heard the conversation on the telephone?”

“I heard what you were saying, but could not understand much of it,” said his visitor in a scared way.

“I have been trying to communicate with Mr. Forbes, but his daughter tells me that the murder of your niece seems to have affected him in a manner which is incomprehensible to her, and even more so to me, though I am acquainted with facts which her father and I have purposely kept from her knowledge.  Mr. Forbes has gone hurriedly to the Home Office.  I suppose you know what that means?  He is about to give the Home Secretary certain information, and it is not for you or me to interfere with his discretion.  Now, if you tell the Scotland Yard people what you have told me, namely, that Mr. Forbes was the intermediary through whom Mrs. Lester received the greater part of her income, he will be brought prominently into the inquiry.  You see that, don’t you?”

“Yes.  I suppose that something of the sort must happen.”

“Well, I want you to suppress that vital fact until we know more about this affair.  It will not be for long.  Each of us must tell our story without reservation at some future date—­ whether this afternoon, or tomorrow, or a week hence, I cannot say now.  But I do ask you to keep your knowledge to yourself until I have had an opportunity of consulting Mr. Forbes.  I undertake to tell you the exact position of matters without delay, and I accept all responsibility for my present advice.”