“My dear young lady,” Inspector Jacks said, “I will not ask for your sympathy, for I am afraid I should ask in vain; but we are just now, we people at Scotland Yard, up against one of the most extraordinary problems which have ever been put before us.  We have had two murders occurring in two days, which have this much, at least, in common—­that they have been the work of so accomplished a criminal that at the present moment, although I should not like to tell every one as much, we have not in either case the ghost of a clue.”

“That sounds very stupid of you,” Penelope remarked, “but I still ask—­”

“Don’t ask for a minute or two,” the Inspector interrupted.  “I think I remarked just now that these two crimes had one thing in common, and that was the fact that they had both been perpetrated by a criminal of unusual accomplishments.  They also have one other point of similitude.”

“What is that?” Penelope asked.

“The victim in both cases was an American,” the Inspector said.

Penelope sat very still.  She felt the steely eyes of the man who had chosen his seat so carefully, fixed upon her face.

“You do not connect the two affairs in any way?” she asked.

“That is what we are asking ourselves,” Mr. Jacks continued.  “In the absence of any definite clue, coincidences such as this are always interesting.  In this case, as it happens, we can take them even a little further.  We find that you, for instance, Miss Penelope Morse, a young American lady, celebrated for her wit and accomplishments, and well known in London society, were to have lunched with Mr. Hamilton Fynes on the day when he made his tragical arrival in London; we find too, curiously enough, that you were one of the party with whom Mr. Richard Vanderpole was to have dined and gone to the theatre on the night of his decease.”

Penelope shivered, and half closed her eyes.

“Don’t you think,” she said, “that the shock of this coincidence, as you call it, has been quite sufficient, without having you come here to remind me of it?”

“Madam,” Mr. Jacks said, “I have not come here to gratify any personal curiosity.  I have come here in the cause of justice.  You should find me a welcome visitor, for both these men who have lost their lives were friends of yours.”

“I should be very sorry indeed,” Penelope answered, “to stand in the way of justice.  No one can hope more fervently than I do that the perpetrator of these deeds will be found and punished.  But what I cannot understand is your coming here and reopening the subject with me.  I tell you again that I have no possible information for you.”

“Perhaps not,” the Inspector declared, “but, on the other hand, there are certain questions which you can answer me,—­answer them, I mean, not grudgingly and as though in duty bound,—­answer them intelligently, and with some apprehension of the things which lie behind.”