"With Mike still chasing him?"

"As hard as he could run, but you know he hasn't much speed."

"I wonder," whispered Alvin, "whether there are any more of them
downstairs."

They stepped noiselessly to the head of the steps and listened.
Everything was so quiet that they heard the ticking of the clock on the
wall of the store.

"I don't believe anyone is there. Let's take a closer look."

Alvin struck a match from his safe and led the way, thus saving the two
from the mishap that had overtaken their friend. They were a trifle
nervous when they stepped upon the lower floor, Alvin maintaining the
illumination by burning more matches. He climbed upon the counter, and
lighted the large oil lamp suspended there for such purpose. Adjusting
the wick to the highest point it would stand without smoking, the two
looked around.

What they saw completed the story that had already taken shape in their
own minds. The unbroken dark lantern lay on the floor where it had
fallen, the light having been extinguished. The raised window showed by
what avenue the burglar and Mike had left the building, but what amazed
the youths more than anything else was the wide open door of the safe.
Not a burglar's tool or device was in sight, and the appearance of the
lock and door without a scratch showing proved that no part of the
structure had been tampered with. It was just as if Mrs. Friestone had
manipulated it--as she had done times without number.

"Whoever opened it must have known the combination. And how did he learn
it?"

Chester shook his head.

"Perhaps Mrs. Friestone can guess. I'll ask her."

Going to the foot of the stairs, the young man called to the woman just
loudly enough for her to hear. He said the visitors had left, but the
door of the safe was open and it was advisable for her to come down and
take a look at things.

She timidly came down the steps, with Nora tremblingly clinging to her
skirts, ready to scream and dash back to the front of the house on the
first appearance of danger. But nothing occurred to cause new alarm, and
mother and daughter stared wonderingly at the safe with its wide open
door.

"Who did that?" asked the woman, in a faint voice.

"One of the burglars," replied Chester.

"How did he learn the combination?"

"That's the mystery; Alvin and I cannot guess. Was it known to anyone
besides yourself?"

"No; I changed it two days ago and did not even tell Nora. Not another
soul knew it--and