“What?” I exclaimed.

“By telephone,” repeated Gatton.  “He was rung up about ten days ago by some one who made a verbal offer to lease the Red House for a period of twelve months.  A foreigner, who in lieu of the usual references, was prepared to pay the annual rent in advance.  As the Red House, to use an Irishism, was regarded as something of a white elephant, the agent was interested, apparently; and when on the following day the sum agreed upon arrived by post, he did not demur about delivering the keys to the prospective lessee, who desired to take certain measurements in regard to carpets and so forth.”

“Wait a moment,” I interrupted; “to whom did he deliver these keys?”

“To a district messenger who called for them, as the agent had been advised that one would do.”

“Very well.  What then?”

“That is all that the agent had to say.”

“What, that is all?”

“Substantially there is nothing more.  It is quite evident that the sole intention of this unknown lessee was to secure possession of the house for the purpose of the crime only.”

“Do you mean that from first to last no one but the district messenger appeared in the matter?”

“No one,” Gatton assured me, “and the rent, payment of which quite disarmed the agent of course, was sent in the form of Treasury notes and not by check.”

“But surely some name, some address, must have been given?”

“A name was given,” replied Gatton, “and a hotel address, but confirmation of their accuracy was never sought, after the receipt of the money.”

“And the voice on the telephone?”

Again I saw that odd expression creep over Gatton’s face, and: 

“It was a woman’s voice,” he answered.

“Great heavens!” I muttered—­“what does it all mean?”

That the evidence of the cabman when he was discovered and of the carter who had taken the box from the garage to the docks, and (for it was possibly the same man) who had first delivered it at the Red House, would but tighten the net about Isobel, whom I knew to be innocent, I felt assured.

“Gatton,” I said, “this case appears to me to resolve itself into a deliberate conspiracy of which the end was not the assassination of Sir Marcus, but the conviction of Miss Merlin!”

Gatton looked at me with evident complexity written all over him.

“I begin to think the same,” he confessed.  “This business was never planned and carried out by a woman, I’ll swear to that.  There is a woman concerned in it, for at every point we come upon evidence of her voice issuing the mysterious instructions; but she is not alone in the matter.  Already the intricacy of the thing points to a criminal of genius.  When we know the whole truth, if we ever do, that the crime was planned by a man of amazing, if perverted, intellect, will be put beyond dispute, I think.”

“What is puzzling me, Gatton,” I said, “is the connection existing between the incidents which took place in this garage and those, unknown at present, which took place in the furnished room in the Red House.”