s the matter?" asked the soldier, running to catch up with
the boys. "Ugly greasers?"

"No," replied Donald, "we're shadowing a man who is wanted by
Gen. Funston. That's him," pointing; "keep your eye on him."

"I thought you chaps had something on," laughed the soldier. "You
can bet on me!"

Now that they approached nearer the center of the business
portion of the city, there were more people on the street; but
they were so near their quarry that they easily kept him in
sight. Only once had he glanced back, but that was enough to
convince him that he was followed.

"He's headed for somewhere," said Adrian. "He doesn't expect to
get away from us simply by walking."

"Right," agreed Donald. "There he goes into the post office."

"Yes," from Adrian, "and it has two doors. You stop at the first
one and I'll run to the other."

He started on a run and the soldier followed suit.

The sight of a man running and a soldier following, quickly
attracted attention and pedestrians began to stop and see what
the matter might be. In less than a minute a crowd had collected,
among them several soldiers, who quickly brought Adrian to a
halt.

"What's the matter?" asked one. Then as the soldier came up:
"What are you chasing him for?"

"I'm not chasing him," laughed the seeming pursuer. "He and I are
after another chap."

The delay occasioned by this interference was not great, but it
was sufficient to allow Strong to escape, had it not been for
Donald. He had seen the crowd gathering and, realizing what would
happen, ran around the other way, just in time to see Strong
disappearing around the corner of the street on which the bank
was located.

Madly he dashed down the street and turned the corner in time to
see Strong enter the big gate leading into the patio of Don
Esteban's residence.

Putting on more steam, a couple of minutes later Donald also
dashed into the patio; but Strong was nowhere to be seen.

"He must be in the bank," muttered the boy, and he quickly
entered the door.

But Strong had disappeared as completely as though the earth had
opened and swallowed him up.

CHAPTER XXX.

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 be