Sergeant Sowerby digested these words, composing his jovial countenance in an expression of unnatural profundity.  Then:—­

“The point to my mind,” he said, “is the one raised by Mr. Hilton.  By gum! didn’t Dr. Cumberly tell him off!”

“Dr. Cumberly,” replied Dunbar, “is entitled to his opinion, that the injection in the woman’s shoulder was at least eight hours old; whilst Mr. Hilton is equally entitled to maintain that it was less than one hour old.  Neither of them can hope to prove his case.”

“If either of them could?"...

“It might make a difference to the evidence—­but I’m not sure.”

“What time is your appointment?”

“Ten o’clock,” replied Dunbar.  “I am meeting Mr. Debnam—­the late Mr. Vernon’s solicitor.  There is something in it.  Damme!  I am sure of it!”

“Something in what?”

“The fact that Mr. Vernon died yesterday evening, and that his wife was murdered at midnight.”

“What have you told the press?”

“As little as possible, but you will see that the early editions will all be screaming for the arrest of Soames.”

“I shouldn’t wonder.  He would be a useful man to have; but he’s probably out of London now.”

“I think not.  He’s more likely to wait for instructions from his principal.”

“His principal?”

“Certainly.  You don’t think Soames did the murder, do you?”

“No; but he’s obviously an accessory.”

“I’m not so sure even of that.”

“Then why did he bolt?”

“Because he had a guilty conscience.”

“Yes,” agreed Sowerby; “it does turn out that way sometimes.  At any rate, Stringer is after him, but he’s got next to nothing to go upon.  Has any reply been received from Mrs. Leroux in Paris?”

“No,” answered Dunbar, frowning thoughtfully.  “Her husband’s wire would reach her first thing this morning; I am expecting to hear of a reply at any moment.”

“They’re a funny couple, altogether,” said Sowerby.  “I can’t imagine myself standing for Mrs. Sowerby spending her week-ends in Paris.  Asking for trouble, I call it!”

“It does seem a daft arrangement,” agreed Dunbar; “but then, as you say, they’re a funny couple.”

“I never saw such a bundle of nerves in all my life!"...

“Leroux?”

Sowerby nodded.

“I suppose,” he said, “it’s the artistic temperament!  If Mrs. Leroux has got it, too, I don’t wonder that they get fed up with one another’s company.”

“That’s about the secret of it.  And now, I shall be glad, Sowerby, if you will be after that taxi-man again.  Report at one o’clock.  I shall be here.”

With his hand on the door-knob:  “By the way,” said Sowerby, “who the blazes is Mr. King?”

Inspector Dunbar looked up.

“Mr. King,” he replied slowly, “is the solution of the mystery.”

VII