“If my departure for France will relieve Miss Forbes of anxiety on your behalf, I’ll go,” he vowed.

Forbes regarded him with a new interest.

“I believe you mean that,” he said.

“I do.”

“But I cannot send you out of the country on a false pretense.  It was your safety and well-being, not my daughter’s, that I was thinking of.”

“What have I to fear?”

“I do not know.  I am like a man wandering by night in a jungle alive with fearsome beasts and reptiles.”

“Yet you had some reason for suggesting my prompt departure.”

“Yes.  It is an absurd thing to say, but I believe I am putting you in danger of your life by coming here this morning.”

“Can’t you speak plainly, Mr. Forbes?  What good purpose do you serve by holding forth these vague terrors?  If, as Miss Forbes told me, you have visited the Home Office, I take it you made yourself clear to the authorities—­ assuming, that is, you went there in connection with the amazing conditions which seem to be bound up with this crime.”

“There is a certain class of knowledge which is in itself dangerous to those who possess it, no matter whether or not it affects them in any particular.  I recommend you, in good faith, to leave London today.”

“If my own safety is the only consideration I refuse as readily as I agreed before.”

Theydon’s tone grew somewhat impatient.  He really fancied that Forbes was trifling with him.  Indeed, a queer doubt of the man’s complete sanity now peeped up in him.  Forbes was regarded as a crank by a large section of the public on account of his peace propaganda; if that opinion were justified why should he not be eccentric in other respects?

It was fantastic, almost stupid, to look upon him as responsible for Mrs. Lester’s murder, but there was always a possibility that he might be utilizing the chance which led him to her apartments shortly before the crime was committed to cover himself and his movements with a veil of spurious mystery.  In a word, though Theydon had likened his visitor’s face to a mask of ivory he had momentarily forgotten the ominous token found on Mrs. Lester’s body and duplicated in Forbes’s own house by the morning’s post.

Forbes spread wide his hands with the air of one who heard, but was allowing his thoughts to wander.  When next he spoke it was only to increase the crazy inconsequence of their talk.

“Later—­ perhaps today—­ perhaps it may never be necessary—­ I may explain myself to your heart’s content,” he said slowly.  “At present I am here to ask a favor.  In the first place, is Mrs. Lester’s flat in charge of the police?”

“I suppose so,” said Theydon.

“Is there a detective or constable on duty there now?”

“I am not sure.  I imagine there is not.  When the Scotland Yard men and I came out after midnight they locked the door and took away the key.  The—­ er—­ body is at the mortuary, awaiting the opening of the inquest at three o’clock.”