"This came for you two hours ago, sir," he said "We thought you were in Hertford."
"This" was a letter addressed in pencil, and Mr. Milburgh had made no attempt to disguise his handwriting. Tarling tore open the envelope and read the contents:
"Dear Mr. Tarling," it began. "I have just read in the Evening Press, with the deepest sorrow and despair, the news that my dearly Beloved wife, Catherine Rider, has been foully murdered. How terrible to think that a few hours ago I was conversing with her assassin, as I believe Sam Stay to be, and had inadvertently given him information as to where Miss Rider was to be found! I beg of you that you will lose no time in saving her from the hands of this cruel madman, who seems to have only one idea, and that to avenge the death of the late Mr. Thornton Lyne. When this reaches you I shall be beyond the power of human vengeance, for I have determined to end a life which has held so much sorrow and disappointment.—M."
He was satisfied that Mr. Milburgh would not commit suicide, and the information was superfluous that Sam Stay had murdered Mrs. Rider. It was the knowledge that this vengeful lunatic knew where Odette Rider was staying which made Tarling sweat.
"Where is Mr. Whiteside?" he asked.
"He has gone to Cambours Restaurant to meet somebody, sir," said the sergeant.
The somebody was one of Milburgh's satellites at Lyne's Store. Tarling must see him without delay. The inspector had control of all the official arrangements connected with the case, and it would be necessary to consult him before he could place detectives to watch the nursing home in Cavendish Place.
He found a cab and drove to Cambours, which was in Soho, and was fortunate enough to discover Whiteside in the act of leaving.
"I didn't get much from that fellow," Whiteside began, when Tarling handed him the letter.
The Scotland Yard man read it through without comment and handed it back.