"There is no doubt," the right honourable gentleman continued, "that the person who took charge of this affair is exceedingly clever. He appears to have resource and daring. Personally, I, like you, never believed for a moment that the whole of the records of German espionage in America for the last three years, would be found upon the same steamer as that by which the departing ambassadorial staff travelled. However, I can quite see that under the circumstances you had to yield to the convictions of those who were already in charge of the affair." "You have had full reports, sir, I suppose?" Crawshay asked. "You know the manner in which the documents were brought into this country?" "A ghastly business," Mr. Brown acknowledged, "ingenious but ghastly. Yes, Mr. Crawshay," he went on, "I think I have been kept pretty well posted up till now. I have sent for you because I am not sure whether one point has been sufficiently impressed upon you. As you are of course aware, there are many documents and details connected with this propaganda which are of immense value to the police of New York, but there is just one--a letter written in a moment of impulse by one great personage to another, and stolen--which might do the cause of the Allies incalculable harm if it were to fall into the wrong hands." "I had a hint of this, sir. Mason knew of it, too. His idea was that they would be quite willing to destroy all the rest of the treasonable stuff they have, if they could be sure of getting this one letter through." "The documents have been in England now," Mr. Brown observed, "for some days. Have you formed any theory at all as to where they may be concealed?" "To be perfectly frank," Crawshay confessed, "I have not. Doctor Gant, Jocelyn Thew, a young woman called Nora Sharey, and Miss Beverley are the four people possibly implicated in their disappearance, although of these two I consider Miss Sharey and Miss Beverley out of the question. Nevertheless, their rooms and every scrap of property they possess have been searched thoroughly, and their movements since they arrived in London are absolutely tabulated. Not one of them has written a letter or dispatched a parcel which has not been investigated, nor have they made a call or even entered a shop without being watched. It seems absolutely impossible that they can have taken any steps towards the disposal of the documents since Jocelyn Thew arrived in London." "Have they given any indication of their future plans?" "Doctor Gant," Crawshay replied, "has booked a passage back in the American boat which sails for Liverpool early to-morrow morning. We shall escort him there, and his effects will be searched once more in Liverpool. Otherwise, we have no intention of detaining him. He and Miss Beverley were simply the tools of the other man." "And the other man?"