believe,
and there's a side track there. Have the carriage shunted, and keep
close guard over it until Mr. Narkom and I arrive."

"Right you are, sir. Anything else?"

"Yes. Have the station-master at the junction equip a hand-car with a
searchlight, and send it here as expeditiously as possible. If anybody
or anything has left this train between this point and Honor Oak Park,
Mr. Narkom, this thin coating of snow will betray the fact beyond the
question of a doubt."

Twenty minutes later the hand-car put in an appearance, manned by a
couple of linemen from the junction, and, word having been wired up the
line to hold back all trains for a period of half an hour in the
interests of Scotland Yard, Cleek and Narkom boarded the vehicle, and
went whizzing up the metals in the direction of Honor Oak Park, the
shifting searchlight sweeping the path from left to right and glaring
brilliantly on the surface of the fallen snow.

Four lines of tracks gleamed steel-bright against its spotless
level--the two outer ones being those employed by the local trains going
to and fro between London and the suburbs, the two inner ones belonging
to the main line--but not one footstep indented the thin surface of that
broad expanse of snow from one end of the journey to the other.

"The murderer, whoever he is or wherever he went, never set foot upon so
much as one inch of this ground, that's certain," said Narkom, as he
gave the order to reverse the car and return. "You feel satisfied of
that, do you not, my dear fellow?"

"Thoroughly, Mr. Narkom; there can't be two opinions upon that point.
But, at the same time, he _did_ leave the train, otherwise we should
have found him in it."

"Granted. But the question is, _when_ did he get in and _how_ did he get
out? We know from the evidence of the passengers that the train never
stopped for one instant between London Bridge station and Anerley; that
all compartments were alight up to the time it passed Honor Oak Park;
that nobody abroad of it heard a sound of a pistol-shot; that the
assassin could not have crept along the footboard and got into some
other compartment, for _all_ were so densely crowded that half a dozen
people were standing in each, so he could not have entered without
somebody making room for him to open the door and get in. No such thing
happened, no such thing could happen, without a dozen or more people
being aware of it; so the idea of a confederate may be dismissed wi