Besides, this explanation ignored the man in
the smoking carriage, and gave no reason at all for his simultaneous
disappearance. The police had little difficulty in showing that such a
theory would not cover the facts, but they were unprepared in the
absence of evidence to advance any alternative explanation. There was a letter in the _Daily Gazette_, over the signature of a
well-known criminal investigator, which gave rise to considerable
discussion at the time. He had formed a hypothesis which had at least
ingenuity to recommend it, and I cannot do better than append it in his
own words. “Whatever may be the truth,” said he, “it must depend upon some
bizarre and rare combination of events, so we need have no hesitation in
postulating such events in our explanation. In the absence of data we
must abandon the analytic or scientific method of investigation, and
must approach it in the synthetic fashion. In a word, instead of taking
known events and deducing from them what has occurred, we must build up
a fanciful explanation if it will only be consistent with known events. We can then test this explanation by any fresh facts which may arise. If
they all fit into their places, the probability is that we are upon the
right track, and with each fresh fact this probability increases in a
geometrical progression until the evidence becomes final and convincing. “Now, there is one most remarkable and suggestive fact which has not
met with the attention which it deserves. There is a local train running
through Harrow and King’s Langley, which is timed in such a way that the
express must have overtaken it at or about the period when it eased down
its speed to eight miles an hour on account of the repairs of the line. The two trains would at that time be travelling in the same direction at
a similar rate of speed and upon parallel lines. It is within everyone’s
experience how, under such circumstances, the occupant of each carriage
can see very plainly the passengers in the other carriages opposite to
him. The lamps of the express had been lit at Willesden, so that each
compartment was brightly illuminated, and most visible to an observer
from outside. “Now, the sequence of events as I reconstruct them would be after this
fashion. This young man with the abnormal number of watches was alone in
the carriage of the slow train. His ticket, with his papers and gloves
and other things, was, we will suppose, on the seat beside him. He was
probably an American, and also probably a man of weak intellect. The
excessive wearing of jewellery is an early symptom in some forms of
mania. “As he sat watching the carriages of the express which were (on
account of the state of the line) going at the same pace as himself, he
suddenly saw some people in it whom he knew. We will suppose for the
sake of our theory that these people were a woman whom he loved and a
man whom he hated—and who in return hated him. The young man was
excitable and impulsive. He opened the door of his carriage, stepped
from the footboard of the local train to the footboard of the express,
opened the other door, and made his way into the presence of these two
people. The feat (on the supposition that the trains were going at the
same pace) is by no means so perilous as it might appear. “Having now got our young man without his ticket into the carriage in
which the elder man and the young woman are travelling, it is not
difficult to imagine that a violent scene ensued. It is possible that
the pair were also Americans, which is the more probable as the man
carried a weapon—an unusual thing in England. If our supposition of
incipient mania is correct, the young man is likely to have assaulted
the other. As the upshot of the quarrel the elder man shot the intruder,
and then made his escape from the carriage, taking the young lady with
him. We will suppose that all this happened very rapidly, and that the
train was still going at so slow a pace that it was not difficult for
them to leave it. A woman might leave a train going at eight miles an
hour. As a matter of fact, we know that this woman _did_ do so. “And now we have to fit in the man in the smoking carriage. Presuming
that we have, up to this point, reconstructed the tragedy correctly, we
shall find nothing in this other man to cause us to reconsider our
conclusions. According to my theory, this man saw the young fellow cross
from one train to the other, saw him open the door, heard the
pistol-shot, saw the two fugitives spring out on to the line, realized
that murder had been done, and sprang out himself in pursuit. Why he has
never been heard of since—whether he met his own death in the pursuit,
or whether, as is more likely, he was made to realize that it was not a
case for his interference—is a detail which we have at present no means
of explaining. I acknowledge that there are some difficulties in the
way. At first sight, it might seem improbable that at such a moment a
murderer would burden himself in his flight with a brown leather bag. My
answer is that he was well aware that if the bag were found his identity
would be established. It was absolutely necessary for him to take it
with him. My theory stands or falls upon one point, and I call upon the
railway company to make strict inquiry as to whether a ticket was found
unclaimed in the local train through Harrow and King’s Langley upon the
18th of March. If such a ticket were found my case is proved. If not, my
theory may still be the correct one, for it is conceivable either that
he travelled without a ticket or that his ticket was lost.”

  To this elaborate and plausible hypothesis the answer of the police
and of the company was, first, that no such ticket was found; secondly,
that the slow train would never run parallel to the express; and,
thirdly, that the local train had been stationary in King’s Langley
Station when the express, going at fifty miles an hour, had flashed past
it. So perished the only satisfying explanation, and five years have
elapsed without supplying a new one. Now, at last, there comes a
statement which covers all the facts, and which must be regarded as
authentic. It took the shape of a letter dated from New York, and
addressed to the same criminal investigator whose theory I have quoted. It is given here in extenso, with the exception of the two opening
paragraphs, which are personal in their nature:—

 “You’ll excuse me if I’m not very free with names. There’s less reason
now than there was five years ago when mother was still living. But for
all that, I had rather cover up our tracks all I can. But I owe you an
explanation, for if your idea of it was wrong, it was a mighty ingenious
one all the same. I’ll have to go back a little so as you may understand
all about it. “My people came from Bucks, England, and emigrated to the States in
the early fifties. They settled in Rochester, in the State of New York,
where my father ran a large dry goods store.