* * * *

Naturally, the mystery of the night express caused a great sensation.
Nothing like it had been known since the great crime on the South Coast,
which is connected with the name of Lefroy. But that was not so much a
mystery as a man hunt. There the criminal had been identified. But here
there was no trace and no clue whatever. It was in vain that the
Scotland Yard authorities tried to shake the evidence of the guard,
Catesby. He refused to make any admissions that would permit the police
even to build up a theory. He was absolutely certain that Mr. Skidmore
had been alone in the carriage at the moment that the express left
London; he was absolutely certain that he had locked the door of the
compartment, and the engine driver could testify that the train had
never traveled at a less speed than sixty miles an hour until the bridge
over the river leading into Lydmouth station was reached; even then
nobody could have dropped off the train without the risk of certain
death. Inspector Merrick was bound to admit this himself when he went
over the spot. And the problem of the missing bullion boxes was quite as
puzzling in its way as the mysterious way in which Mr. Skidmore had met
his death.

There was no clue to this either. Certainly there had been a struggle,
or there would not have been blood marks all over the place, and the
window would have remained intact. Skidmore had probably been forced
back into his seat, or he had collapsed there after the fatal shot was
fired. The unfortunate man had been shot through the brain with an
ordinary revolver of common pattern, so that for the purpose of proof
the bullet was useless. There were no finger marks on the carriage door,
a proof that the murderer had either worn gloves or that he had
carefully removed all traces with a cloth of some kind. It was obvious,
too, that a criminal of this class would take no risks, especially as
there was no chance of his being hurried, seeing that he had had three
clear hours for his work. The more the police went into the matter, the
more puzzled they were. It was not a difficult matter to establish the
bona fides of the passengers who traveled in the next coach with
Skidmore, and as to the rest it did not matter. Nobody could possibly
have left any of the corridor coaches without attracting notice; indeed,
the very suggestion was absurd. And there the matter rested for three
days.

It must not be supposed that t