“You are very kind, sir,” said the Inspector.  “I do my best, but I might admit to you that I have never found a case so difficult to grasp.  Our methods perhaps are slow, but they are, in a sense, sure.  We are building up our case, and we hope before long to secure the criminal, but it is not an easy task.”

The Prince bowed.  This time he made no remark.

“The evidence which I have collected from various sources,” Inspector Jacks continued, “leads me to believe that the person who committed this murder was a foreigner.”

“What you call an alien,” the Prince suggested.  “There is much discussion, I gather, concerning their presence in this country nowadays.”

“The evidence which I possess,” the detective proceeded, “points to the murderer belonging to the same nationality as Your Highness.”

The Prince raised his eyebrows.

“A Japanese?” he asked.

The Inspector assented.

“I am sorry,” the Prince said, with a touch of added gravity in his manner, “that one of my race should have committed a misdemeanor in this country, but if that is so, your way, of course, is clear.  You must arrest him and deal with him as an ordinary English criminal.  He is here to live your life, and he must obey your laws.”

“In time, sir,” Inspector Jacks said slowly, “we hope to do so, but over here we may not arrest upon suspicion.  We have to collect evidence, and build and build until we can satisfy any reasonable individual that the accused person is guilty.”

The Prince sighed sympathetically.

“It is not for me,” he said, “to criticize your methods.”

“I come now,” Inspector Jacks said slowly, “to the object of my call upon Your Highness.  Following upon what I have just told you, certain other information has come into my possession to this effect—­that not only was this murderer a Japanese, but we have evidence which seems to suggest that he was attached in some way to your household.”

“To my household!” the Prince repeated.

“To this household, Your Highness,” the detective repeated.

The Prince shook his head slowly.

“Mr. Jacks,” he said, “you are, I am sure, a very clever man.  Let me ask you one question.  Has it ever fallen to your lot to make a mistake?”

“Very often indeed,” the Inspector admitted frankly.

“Then I am afraid,” the Prince said, “that you are once more in that position.  I have attached to my household fourteen Japanese servants, a secretary, a majordomo, and a butler.  It may interest you, perhaps, to know that during my residence in this country not one of my retinue, with the exception of my secretary, who has been in Paris for some weeks, has left this house.”

The Inspector stared at the Prince incredulously.

“Never left the house?” he repeated.  “Do you mean, sir, that they do not go out for holidays, for exercise, to the theatre?”