cut the rope that bound it and Old King Brady pried off the lid with an axe taken from one of the racks.
The conductor held a lantern over the box.
As the lid fell off, they were startled to see the body of a man lying in the box.
His face was partly averted, as he lay upon his side.
But the detectives saw that he was a man of about fifty, his portly form clad in a dark suit of clothes. His head was partly bald on top and his hair was gray. There was a closely-trimmed mustache of the same color on his upper lip, and his flesh, although pallid, had not yet changed to the waxen hue of death.
It was evident that he was a victim of foul play, for his hands were bound behind his back, and his ankles tied together, while a gag was secured over his mouth as if to stifle his outcries.
The detectives had no chance to observe any more, just then, for there suddenly sounded a quick danger signal of the locomotive's whistle.
The engineer shut off steam, put on the brakes, and the startled conductor rushed from the car with the lantern, leaving the place in gloom.
"What can be the matter?" muttered Old King Brady.
"There's a fire on the track ahead!" said Harry, peering out the side door.
"Where are we?" queried the baggage master, hastily.
"Next to a big swamp," replied Harry. "And, by Jove – see – see! There's an obstruction – a heap of sleepers piled across the rails beyond the bonfire."
"What the deuce can that mean?" muttered Old King Brady. "Bandits trying to rob this train? It don't seem possible, in this neighborhood."
The train paused and they all alighted.
Some of the brakemen ran ahead, and under the conductor's direction they removed the obstructions from the rails.
The fire seemed to have been built where it was to show the engineer the pile of sleepers, and the brakemen scattered it, when the barrier was removed.
As the bell rang, every one got aboard and the cars slowly went ahead.
The Bradys and the baggage master returned to the latter's car.
"We'll finish our examination of that body," said Old King Brady.
"Yes," said Harry, "and – Good gracious! Where's the box gone?"
Box and body had vanished.
Every one was astounded.
Then, like a flash, the truth suddenly dawned upon Harry's mind, and he cried:
"Now I see through it. Those obstructions were put on the rails to stop the train at this point so that the body could be removed from this car."
"By whom?" demanded the startled baggage master.
"Accessories of the villain who killed that man!" cried the boy. "They've carried the body off in the swamp to hide the evidence of their crime. Come, Old King Brady, alight here and see if we can trace it."
The detectives made a rush for the door and leaped from the train.
They landed beside the roadbed, and the cars went on without them.
CHAPTER III.
THE GREAT SWAMP MYSTERY
Heavy banks of dark clouds were flying across the lowering sky. Occasionally the big silvery moon burst from the rifts and flooded the landscape with its mellow light.
During one of these intervals the two detectives gazed around.
The train had disappeared in the distance.
Not far away from where the Bradys stood they saw the big box lying beside the track, turned over on its side.
They ran back and hastily examined it.
"Empty!" ejaculated Harry, in some surprise.
"What has become of the man it contained?" asked Old King Brady.
"Search. He may have fallen out."
They carefully examined the ground within a wide radius.
But they found nothing of the missing body.
"Mysterious, what became of him!" Old King Brady exclaimed.
Harry was completely at his wits' end.
"I'm afraid we are beyond our depth, Old King Brady," he remarked. "This mystery keeps growing all the time, and we can't seem to fathom it."
Just then the moon appeared again.
It showed them a river on one side and a broad expanse of gloomy swamp land on the other.
Night insects were chirping amid the weeds, and frogs were croaking dismally among the waving reeds and rushes.
Off in the centre of the swamp were some tangled trees and bushes, heaps of rocks overgrown with moss and trailing vines, and an object which had the dim outline of being an old rookery of some sort.
It was a dismal, lonesome scene.
Young King Brady moved along the edge of the boggy ground with its little pools of water, tufts of coarse grass and tracts of black, oozing mud.
An old, rotten board walk from the railroad bed to the trees, caught his view and he suddenly called to the old detective:
"I see a light among those trees. Here's a path. Let's follow it into the swamp."
"Be cautious!" warned the old detective. "If those rascals have carried the body from the box to the midst of those trees, they will be on the lookout for any possible pursuers and may give us a warm reception."
"We need not let ourselves be seen," replied the boy.
"How are you going to avoid it?"
"By creeping along the path on our hands and knees. The reeds on each side will hide our bodies from view."
"Go ahead, then."
They went down on their haunches and crept along in single file, out into the dismal swamp, and drew near the oasis.
In a few minutes they reached firm land.
From behind a clump of bushes they beheld an old wooden shanty, in the windows of which there glowed a dim light.
The detectives keenly watched it, hoping they might catch view of some human beings about the place.
At the end of quarter of an hour, they were suddenly startled by hearing a wild, piercing cry in human tones, of:
"Help! Police! Murder!"
The Bradys were intensely startled.
It was the same voice, using the very same words they had heard the night before in West Thirty-sixth street, New York!
"Good
