Why see such a man personally?
Why give a key to a gate, or a door, which could be left open?
Why give a scrap of writing or paper of any sort?
Why offer such ridiculous sums of money to a stranger, who, if he were such a man as suggested, would have accepted a fraction of the amount for such work?
If an investigation of the alleged proofs could show there was any semblance of truth in this story, then, indeed, "it certainly would not have deceived a schoolboy," as the letter quotes.
Assuming, for the sake of argument, that an alien to a neutral country (whosoever that person might be or in whatsoever walk of life he might happen to be placed) had made himself a danger to the realm; that it might have been considered an advantage to the Allies if he were kidnapped and taken to a place of safe keeping so that he could be looked after until peace was declared. What more simple and inexpensive than to bring about a consummation of such wishes? Our friend Nixie Pixie, or Jim, or another of that ilk, any one of those individuals could have acted secretly and absolutely independently.
What could have been easier or more inexpensive than a quickly-cultivated acquaintanceship by a Secret Service agent with a person so named? A little dinner or light refreshment at a café, or a hall; drugged food or drink, followed by the natural announcement that one's companion was temporarily indisposed or suffering from a slight excess of alcohol; assistance to a cab or other vehicle, nominally to convey him home but actually a quick journey to the docks and quay side, with rapid transport to a friendly ship! Thus such a job could have been accomplished for a few pounds without fuss, inconvenience, or publicity.
It would probably not be wide of the mark to venture the statement that many a man has been, perhaps even now is being, temporarily detained in the seclusion of some lonely lodging upon far less pretexts than the alleged revelations of Sir Roger Casement, until this tangled European skein be fully and completely unravelled. The annals of that grim fortress of Peter and Paul, the dungeon walls of which are washed by the turbid waters of the Neva (wherein the author has had personal experience of his own), could perhaps add histories of some interest, but if they are to be told they must form the pages of another chapter.