THE MYSTERY SOLVED.
When the opening at the head of the stairs had closed upon Billie
and he realized that he was shut in a subterranean passage, for a
minute his heart sank within him.
He had tried to find an opening at the top of the opposite stairs
and had failed, and he did not know that he would have any better
success in trying to find a way to open the place through which
he had descended.
"Nobody on earth knows that I am down here," he thought, "and
with Santiago sick and maybe dying, no one on earth probably
knows that there is such a passage."
But Billie was not the lad to sit down and cry. He had been in
tight places before and he had an abiding faith in his own
ability to do things. Therefore, he called up his courage and
slowly mounted the stairs leading to Santiago's patio.
At the top of the stairs he found himself confronted by exactly
the same condition as he had found on the opposite side.
"But there is this difference," muttered Billie. "I know that
there must be some sort of a crack where that slab fell back."
He held the electric bull's-eye close to the stone and
scrutinized every spot.
Not a single crack could he spy.
Then he took out his big jack-knife and prodded with it clear
across the width of the stairway.
There was nothing but solid stone.
"Looks kind o' desperate," he told himself, "but I have simply
got to find an opening."
Again he prodded the place over without result.
"It's no use," he finally said to himself. "If I am to get out of
here, help will have to come from somewhere outside. But how can
it?"
He sat down on the stairs and thought deeply.
"If it is as I think," he mused, "these stairs have been used
recently. The very fact that Ambrosio is prowling around here is
proof that Strong must have been here at some time. But where is
Strong?"
He slid down several steps and threw the light of his torch
across to the opposite stairs.
"Bang!" went something that sounded like a falling stone.
Billie sprang to his feet.
"Click! Bang!" and down the opposite stairway streamed a ray of
light.
Billie shut off his electric torch and waited.
Then on the steps there appeared a foot, then another, until a
whole human body was in sight. Then "click, snap!" and the light
disappeared.
"By George!" exclaimed Billie under his breath, "there's a man on
the stairs right opposite to me. Who on earth can it be?"
His first inclination was to turn on the light, but on second
thought he decided not to.
"I'll let him set the copy," thought Billie. "It's a mighty good
thing to be able to spring the surprise."
He drew his automatic and stood ready for any emergency.
It was still as a tomb.
He could hear his own heart beat and he could also hear the heavy
breathing of the other man.
"Sounds like he had been running and was just catching his
breath," was Billie's mental comment.
After some minutes the man's breathing became more quiet and
Billie heard him slowly descending the stairs.
"This won't do," thought Billie. "He probably has some kind of a
light, and if he gets on the landing and I'm up here, I'll be
like a man up a tree."
The lad sat down and slowly slid toward the bottom.
Being only a few steps from the landing, Billie was down first.
He crowded to the right and listened.
The other was now nearly on the landing. Now he was on the
landing, hugging the wall on the side opposite Billie. Now they
passed each other, or rather the man passed Billie, for Billie
stood perfectly still.
It seemed as though he must hear Billie's breathing, but if he
heard anything he must have thought it his own echo, never
dreaming that he was not alone in the passage.
Now Billie could hear him ascending the stairs leading to
Santiago's house, and his hope rose high.
"He must know how to open the floor," thought Billie. "I'll be
right there when he does."
Silently as a cat Billie crept up the stairs behind his unknown
companion.
Near the top the man stopped and a minute later he flashed an
electric light against the stone overhead. Another minute and he
heaved with the top of his head and the slab slid back.
"And now," exclaimed Billie in a deep voice, "put your hands over
your head!"
Whether from fear or from the unparalleled surprise caused by
hearing a human voice at such a time and in such a place, instead
of obeying Billie's command, Strong's hands--for Strong it
was--fell limp at his side and his electric torch fell to the
stones beneath his feet.
"All right," continued Billy, "if that's the way you feel about
it; but just remember that a single false move and I'll cut this
automatic loose among your ribs. Now climb out a step at a time."
With face as white as marble at the shock he had just sustained,
Strong obeyed implicitly and Billie was soon standing on the
stone patio, looking Strong in the face.
"You're a good one, you are," he said sarcastically. "I should
think you'd be ashamed to call yourself an American."
"What do you mean?" asked Strong in a trembling voice.
"Why, first of all, stealing from the bank, and then selling your
own countrymen to the Mexicans."
"Who have I sold?"
"Do you mean to say that you didn't sell Gen. Funston to the
greasers for ten thousand dollars?"
"Of course I do!" in a somewhat stronger voice.
"Perhaps you'll deny that you are Strong, the mountebank. You
don't think for one minute that I don't know you in spite of your
make-up, do you?"
"No, I'll admit that I'm the mountebank. As for my name that is
of small importance in a country like this. But I did not sell
Gen. Funston, as you put it. I knew the man I pointed out was not
Funston and I knew that as soon as the Mexicans found it out they
would let him go. Some one might have told them rightly. As it
was I spoiled their game and I got the money. Do you think it any
crime to do that?"
"That's a matter I am not in a position to discuss," was Billie's
answer. "But how about robbing the bank?"
"I had as much right to the box as any one."
"You'll have to prove that to some one besides me; all I can do
is to turn you over to the authorities."
"Never!" cried Strong. "I'll die before I'll rot in a Mexican
jail!"
He uttered a peculiar noise and before Billie could imagine what
it meant, he felt himself seized from behind by a pair of hairy
hands.
He had been in that clutch once before and recognized in an
instant that he was in the grip of the ape.
He gave one loud cry for help and then turned loose with his
automatic.
The tumult which followed is beyond description. Billie's shout
was as nothing compared to the cry of the ape as one of the
bullets struck him in the leg and another pierced his foot.
Loosing his hold upon the lad, he grabbed for the weapon, but
Billie managed to evade him and would undoubtedly have slain the
animal had not Strong sprung to his assistance, with the result
that in another minute Billie was disarmed.
Ill would the lad have fared then, at the hands of his two
assailants, had not the noise attracted to the scene several
soldiers, while an instant later came a loud shout as Donald and
Adrian dashed into the patio.
On the other side of the square they had heard Billie's shout,
followed by the automatic, and had rushed to his aid.
In another minute both Strong and his hairy friend were overcome
and securely bound.
"Where did you find him?" asked Donald, pointing to Strong.
"Down there," was Billie's reply, as he pointed toward the still
open underground passage way.
"How did he get there?"
"I suppose he entered from a similar entrance in Don Esteban's
patio. I have had an idea all the time that there was some reason
for the position of these two houses."
"But it doesn't lead into the bank. How could he steal the box
out of the vault?"
"There is the real thief!" exclaimed Billie, pointing to the ape.
"He sneaked in while Strong kept the bank employés engaged. By
some mistake in his understanding he put the envelope back in the
bank the next day instead of putting back the box. It was he who
crawled through the bars into Santiago's library. He was also the
devil who scared the maid almost into fits."
"Well! Well!" exclaimed a voice from the gateway. "I never could
have believed it."
The voice was that of Don Esteban, who had entered while Billie
was speaking.
"I have come to see this strange man, Santiago Ojeda," he
explained. "What says the doctor?"
"Here comes the doctor now," announced Adrian as the physician
made his appearance in the gateway. "He can speak for himself."